From 2fcdc5c5cb12350ecf846cca25d979cc7f832965 Mon Sep 17 00:00:00 2001
From: Tobias <tortmayr@eclipsesource.com>
Date: Tue, 23 Jun 2026 00:49:21 +0200
Subject: [PATCH] GLSP-1635: Migrate spec assertions to native Vitest matchers

- Convert all Chai-style BDD assertions (`.to.be.true`,
  `.to.deep.equal`, `.to.include.members`, ...) across the CLI specs
  to native Vitest matchers; they previously passed only via Vitest's
  bundled Chai-compatible API
- Drop the now-redundant eslint-plugin-chai-friendly and restore the
  plain no-unused-expressions rule, since the converted assertions are
  method calls rather than bare expression statements
- Remove the stale mocha global from the shared eslint base config

Also:
- Add a root test:coverage script
- Drop dead ctrf/ and .nyc_output/ entries from .gitignore

Part of: eclipse-glsp/glsp#1635
---
 .gitignore                                    |   2 -
 dev-packages/cli/src/cli.spec.ts              | 258 +++++++++---------
 .../cli/src/commands/releng/common.spec.ts    |  82 +++---
 .../cli/src/commands/releng/publish.spec.ts   |  32 +--
 .../cli/src/commands/releng/version.spec.ts   |  14 +-
 .../cli/src/commands/repo/build.spec.ts       |  34 +--
 .../cli/src/commands/repo/clone.spec.ts       |  30 +-
 .../src/commands/repo/common/utils.spec.ts    |  50 ++--
 .../cli/src/commands/repo/fork.spec.ts        |  46 ++--
 .../cli/src/commands/repo/link.spec.ts        |  84 +++---
 .../cli/src/commands/repo/repo.spec.ts        |  10 +-
 .../cli/src/commands/repo/run.spec.ts         |  12 +-
 .../cli/src/commands/repo/server-node.spec.ts |  10 +-
 .../cli/src/commands/repo/start.spec.ts       |  20 +-
 .../cli/src/commands/repo/switch.spec.ts      |  22 +-
 .../cli/src/commands/repo/workspace.spec.ts   |  52 ++--
 .../cli/src/commands/update-next.spec.ts      |  12 +-
 dev-packages/cli/src/util/file-util.spec.ts   |  32 +--
 dev-packages/cli/src/util/git-util.spec.ts    |  34 +--
 .../cli/src/util/glsp-repo-util.spec.ts       |  14 +-
 .../cli/src/util/package-util.spec.ts         |  16 +-
 .../cli/src/util/process-util.spec.ts         |  12 +-
 .../cli/src/util/validation-util.spec.ts      |  12 +-
 .../cli/tests/e2e/check-header.e2e.spec.ts    |  44 +--
 .../cli/tests/e2e/generate-index.e2e.spec.ts  |  44 +--
 .../cli/tests/e2e/releng/prepare.e2e.spec.ts  |  84 +++---
 .../cli/tests/e2e/releng/version.e2e.spec.ts  |  64 ++---
 .../e2e/repo/repo-core-build.e2e.spec.ts      |  56 ++--
 .../e2e/repo/repo-core-clone.e2e.spec.ts      |  80 +++---
 .../tests/e2e/repo/repo-eclipse.e2e.spec.ts   |   8 +-
 .../cli/tests/e2e/repo/repo-theia.e2e.spec.ts |   6 +-
 .../tests/e2e/repo/repo-vscode.e2e.spec.ts    |  30 +-
 .../cli/tests/e2e/update-next.e2e.spec.ts     |   6 +-
 dev-packages/config/package.json              |   1 -
 dev-packages/eslint-config/configs/base.js    |   3 -
 dev-packages/eslint-config/configs/errors.js  |   4 +-
 dev-packages/eslint-config/package.json       |   1 -
 package.json                                  |   1 +
 pnpm-lock.yaml                                |  16 --
 39 files changed, 653 insertions(+), 685 deletions(-)

diff --git a/.gitignore b/.gitignore
index 3db0f97..540cb48 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,9 +4,7 @@ lib
 dist
 tsconfig.tsbuildinfo
 eslint.xml
-ctrf/
 coverage/
-.nyc_output/
 
 # Agent specific files
 .claude/plans
diff --git a/dev-packages/cli/src/cli.spec.ts b/dev-packages/cli/src/cli.spec.ts
index 7e8fc6a..d99a61d 100644
--- a/dev-packages/cli/src/cli.spec.ts
+++ b/dev-packages/cli/src/cli.spec.ts
@@ -30,12 +30,12 @@ const optionLongs = (cmd: Command): string[] => cmd.options.map(o => o.long!);
 const subcommandNames = (cmd: Command): string[] => cmd.commands.map(c => c.name());
 const findSub = (parent: Command, name: string): Command => {
     const sub = parent.commands.find(c => c.name() === name);
-    expect(sub, `subcommand '${name}' not found on '${parent.name()}'`).to.exist;
+    expect(sub, `subcommand '${name}' not found on '${parent.name()}'`).toBeDefined();
     return sub!;
 };
 const choices = (cmd: Command, long: string): string[] | undefined => {
     const opt = cmd.options.find(o => o.long === long);
-    expect(opt, `option '${long}' not found on '${cmd.name()}'`).to.exist;
+    expect(opt, `option '${long}' not found on '${cmd.name()}'`).toBeDefined();
     return opt!.argChoices;
 };
 
@@ -47,63 +47,67 @@ describe('cli', () => {
     describe('top-level commands', () => {
         describe('checkHeaders', () => {
             it('should accept a <rootDir> argument', () => {
-                expect(CheckHeaderCommand.registeredArguments).to.have.lengthOf(1);
-                expect(CheckHeaderCommand.registeredArguments[0].name()).to.equal('rootDir');
-                expect(CheckHeaderCommand.registeredArguments[0].required).to.be.true;
+                expect(CheckHeaderCommand.registeredArguments).toHaveLength(1);
+                expect(CheckHeaderCommand.registeredArguments[0].name()).toBe('rootDir');
+                expect(CheckHeaderCommand.registeredArguments[0].required).toBe(true);
             });
 
             it('should have expected options', () => {
-                expect(optionLongs(CheckHeaderCommand)).to.include.members([
-                    '--type',
-                    '--fileExtensions',
-                    '--exclude',
-                    '--no-exclude-defaults',
-                    '--json',
-                    '--autoFix',
-                    '--commit'
-                ]);
+                expect(optionLongs(CheckHeaderCommand)).toEqual(
+                    expect.arrayContaining([
+                        '--type',
+                        '--fileExtensions',
+                        '--exclude',
+                        '--no-exclude-defaults',
+                        '--json',
+                        '--autoFix',
+                        '--commit'
+                    ])
+                );
             });
 
             it('should restrict --type choices', () => {
-                expect(choices(CheckHeaderCommand, '--type')).to.deep.equal(['full', 'changes', 'lastCommit']);
+                expect(choices(CheckHeaderCommand, '--type')).toEqual(['full', 'changes', 'lastCommit']);
             });
         });
 
         describe('updateNext', () => {
             it('should have alias "u"', () => {
-                expect(UpdateNextCommand.alias()).to.equal('u');
+                expect(UpdateNextCommand.alias()).toBe('u');
             });
 
             it('should accept an optional [rootDir] argument', () => {
-                expect(UpdateNextCommand.registeredArguments).to.have.lengthOf(1);
-                expect(UpdateNextCommand.registeredArguments[0].required).to.be.false;
+                expect(UpdateNextCommand.registeredArguments).toHaveLength(1);
+                expect(UpdateNextCommand.registeredArguments[0].required).toBe(false);
             });
 
             it('should have expected options', () => {
-                expect(optionLongs(UpdateNextCommand)).to.include.members(['--verbose']);
+                expect(optionLongs(UpdateNextCommand)).toEqual(expect.arrayContaining(['--verbose']));
             });
         });
 
         describe('generateIndex', () => {
             it('should accept a variadic <rootDir...> argument', () => {
-                expect(GenerateIndex.registeredArguments).to.have.lengthOf(1);
-                expect(GenerateIndex.registeredArguments[0].variadic).to.be.true;
+                expect(GenerateIndex.registeredArguments).toHaveLength(1);
+                expect(GenerateIndex.registeredArguments[0].variadic).toBe(true);
             });
 
             it('should have expected options', () => {
-                expect(optionLongs(GenerateIndex)).to.include.members([
-                    '--singleIndex',
-                    '--forceOverwrite',
-                    '--match',
-                    '--ignore',
-                    '--style',
-                    '--ignoreFile',
-                    '--verbose'
-                ]);
+                expect(optionLongs(GenerateIndex)).toEqual(
+                    expect.arrayContaining([
+                        '--singleIndex',
+                        '--forceOverwrite',
+                        '--match',
+                        '--ignore',
+                        '--style',
+                        '--ignoreFile',
+                        '--verbose'
+                    ])
+                );
             });
 
             it('should restrict --style choices', () => {
-                expect(choices(GenerateIndex, '--style')).to.deep.equal(['commonjs', 'esm']);
+                expect(choices(GenerateIndex, '--style')).toEqual(['commonjs', 'esm']);
             });
         });
     });
@@ -112,7 +116,7 @@ describe('cli', () => {
 
     describe('releng', () => {
         it('should have version and prepare subcommands', () => {
-            expect(subcommandNames(RelengCommand)).to.include.members(['version', 'prepare']);
+            expect(subcommandNames(RelengCommand)).toEqual(expect.arrayContaining(['version', 'prepare']));
         });
 
         describe('version', () => {
@@ -120,18 +124,18 @@ describe('cli', () => {
 
             it('should accept <versionType> argument with choices', () => {
                 const arg = cmd.registeredArguments[0];
-                expect(arg.name()).to.equal('versionType');
-                expect(arg.required).to.be.true;
-                expect(arg.argChoices).to.deep.equal(['major', 'minor', 'patch', 'custom', 'next']);
+                expect(arg.name()).toBe('versionType');
+                expect(arg.required).toBe(true);
+                expect(arg.argChoices).toEqual(['major', 'minor', 'patch', 'custom', 'next']);
             });
 
             it('should accept optional [customVersion] argument', () => {
-                expect(cmd.registeredArguments[1].name()).to.equal('customVersion');
-                expect(cmd.registeredArguments[1].required).to.be.false;
+                expect(cmd.registeredArguments[1].name()).toBe('customVersion');
+                expect(cmd.registeredArguments[1].required).toBe(false);
             });
 
             it('should have expected options', () => {
-                expect(optionLongs(cmd)).to.include.members(['--verbose', '--repoDir']);
+                expect(optionLongs(cmd)).toEqual(expect.arrayContaining(['--verbose', '--repoDir']));
             });
         });
 
@@ -140,11 +144,11 @@ describe('cli', () => {
 
             it('should accept <versionType> argument with choices', () => {
                 const arg = cmd.registeredArguments[0];
-                expect(arg.argChoices).to.deep.equal(['major', 'minor', 'patch', 'custom', 'next']);
+                expect(arg.argChoices).toEqual(['major', 'minor', 'patch', 'custom', 'next']);
             });
 
             it('should have expected options', () => {
-                expect(optionLongs(cmd)).to.include.members(['--verbose', '--repoDir', '--no-push', '--draft', '--no-check']);
+                expect(optionLongs(cmd)).toEqual(expect.arrayContaining(['--verbose', '--repoDir', '--no-push', '--draft', '--no-check']));
             });
         });
     });
@@ -153,60 +157,57 @@ describe('cli', () => {
 
     describe('repo', () => {
         it('should register all top-level repo subcommands', () => {
-            expect(subcommandNames(RepoCommand)).to.include.members([
-                'clone',
-                'fork',
-                'build',
-                'link',
-                'unlink',
-                'pwd',
-                'log',
-                'workspace'
-            ]);
+            expect(subcommandNames(RepoCommand)).toEqual(
+                expect.arrayContaining(['clone', 'fork', 'build', 'link', 'unlink', 'pwd', 'log', 'workspace'])
+            );
         });
 
         it('should register a subrepo command for each GLSPRepo', () => {
             for (const repoName of GLSPRepo.choices) {
-                expect(subcommandNames(RepoCommand), `subrepo '${repoName}' should be registered`).to.include(repoName);
+                expect(subcommandNames(RepoCommand), `subrepo '${repoName}' should be registered`).toContain(repoName);
             }
         });
 
         it('should have a global --dir option', () => {
-            expect(optionLongs(RepoCommand)).to.include('--dir');
+            expect(optionLongs(RepoCommand)).toContain('--dir');
         });
 
         describe('clone', () => {
             const cmd = findSub(RepoCommand, 'clone');
 
             it('should accept optional [repos...] argument', () => {
-                expect(cmd.registeredArguments[0].variadic).to.be.true;
-                expect(cmd.registeredArguments[0].required).to.be.false;
+                expect(cmd.registeredArguments[0].variadic).toBe(true);
+                expect(cmd.registeredArguments[0].required).toBe(false);
             });
 
             it('should have expected options', () => {
-                expect(optionLongs(cmd)).to.include.members([
-                    '--dir',
-                    '--protocol',
-                    '--branch',
-                    '--fork',
-                    '--override',
-                    '--preset',
-                    '--interactive',
-                    '--no-fail-fast',
-                    '--verbose'
-                ]);
+                expect(optionLongs(cmd)).toEqual(
+                    expect.arrayContaining([
+                        '--dir',
+                        '--protocol',
+                        '--branch',
+                        '--fork',
+                        '--override',
+                        '--preset',
+                        '--interactive',
+                        '--no-fail-fast',
+                        '--verbose'
+                    ])
+                );
             });
 
             it('should restrict --protocol choices', () => {
-                expect(choices(cmd, '--protocol')).to.deep.equal(['ssh', 'https', 'gh']);
+                expect(choices(cmd, '--protocol')).toEqual(['ssh', 'https', 'gh']);
             });
 
             it('should restrict --override choices', () => {
-                expect(choices(cmd, '--override')).to.deep.equal(['rename', 'remove']);
+                expect(choices(cmd, '--override')).toEqual(['rename', 'remove']);
             });
 
             it('should restrict --preset choices', () => {
-                expect(choices(cmd, '--preset')).to.include.members(['core', 'theia', 'vscode', 'eclipse', 'playwright', 'all']);
+                expect(choices(cmd, '--preset')).toEqual(
+                    expect.arrayContaining(['core', 'theia', 'vscode', 'eclipse', 'playwright', 'all'])
+                );
             });
         });
 
@@ -214,16 +215,16 @@ describe('cli', () => {
             const cmd = findSub(RepoCommand, 'fork');
 
             it('should accept required <user> argument', () => {
-                expect(cmd.registeredArguments[0].name()).to.equal('user');
-                expect(cmd.registeredArguments[0].required).to.be.true;
+                expect(cmd.registeredArguments[0].name()).toBe('user');
+                expect(cmd.registeredArguments[0].required).toBe(true);
             });
 
             it('should have expected options', () => {
-                expect(optionLongs(cmd)).to.include.members(['--dir', '--protocol', '--repo', '--preset', '--verbose']);
+                expect(optionLongs(cmd)).toEqual(expect.arrayContaining(['--dir', '--protocol', '--repo', '--preset', '--verbose']));
             });
 
             it('should restrict --protocol choices', () => {
-                expect(choices(cmd, '--protocol')).to.deep.equal(['ssh', 'https', 'gh']);
+                expect(choices(cmd, '--protocol')).toEqual(['ssh', 'https', 'gh']);
             });
         });
 
@@ -231,15 +232,9 @@ describe('cli', () => {
             const cmd = findSub(RepoCommand, 'build');
 
             it('should have expected options', () => {
-                expect(optionLongs(cmd)).to.include.members([
-                    '--dir',
-                    '--repo',
-                    '--preset',
-                    '--electron',
-                    '--no-java',
-                    '--no-fail-fast',
-                    '--verbose'
-                ]);
+                expect(optionLongs(cmd)).toEqual(
+                    expect.arrayContaining(['--dir', '--repo', '--preset', '--electron', '--no-java', '--no-fail-fast', '--verbose'])
+                );
             });
         });
 
@@ -247,7 +242,7 @@ describe('cli', () => {
             const cmd = findSub(RepoCommand, 'link');
 
             it('should have expected options', () => {
-                expect(optionLongs(cmd)).to.include.members(['--dir', '--repo', '--preset', '--no-fail-fast', '--verbose']);
+                expect(optionLongs(cmd)).toEqual(expect.arrayContaining(['--dir', '--repo', '--preset', '--no-fail-fast', '--verbose']));
             });
         });
 
@@ -255,7 +250,7 @@ describe('cli', () => {
             const cmd = findSub(RepoCommand, 'unlink');
 
             it('should have expected options', () => {
-                expect(optionLongs(cmd)).to.include.members(['--dir', '--repo', '--preset', '--no-fail-fast', '--verbose']);
+                expect(optionLongs(cmd)).toEqual(expect.arrayContaining(['--dir', '--repo', '--preset', '--no-fail-fast', '--verbose']));
             });
         });
 
@@ -263,7 +258,7 @@ describe('cli', () => {
             const cmd = findSub(RepoCommand, 'pwd');
 
             it('should have expected options', () => {
-                expect(optionLongs(cmd)).to.include.members(['--dir', '--raw', '--verbose']);
+                expect(optionLongs(cmd)).toEqual(expect.arrayContaining(['--dir', '--raw', '--verbose']));
             });
         });
 
@@ -271,7 +266,7 @@ describe('cli', () => {
             const cmd = findSub(RepoCommand, 'log');
 
             it('should have expected options', () => {
-                expect(optionLongs(cmd)).to.include.members(['--dir', '--repo', '--preset', '--verbose']);
+                expect(optionLongs(cmd)).toEqual(expect.arrayContaining(['--dir', '--repo', '--preset', '--verbose']));
             });
         });
 
@@ -279,14 +274,14 @@ describe('cli', () => {
             const workspace = findSub(RepoCommand, 'workspace');
 
             it('should have init and open subcommands', () => {
-                expect(subcommandNames(workspace)).to.include.members(['init', 'open']);
+                expect(subcommandNames(workspace)).toEqual(expect.arrayContaining(['init', 'open']));
             });
 
             describe('init', () => {
                 const cmd = findSub(workspace, 'init');
 
                 it('should have expected options', () => {
-                    expect(optionLongs(cmd)).to.include.members(['--dir', '--output', '--repo', '--preset', '--verbose']);
+                    expect(optionLongs(cmd)).toEqual(expect.arrayContaining(['--dir', '--output', '--repo', '--preset', '--verbose']));
                 });
             });
 
@@ -294,7 +289,7 @@ describe('cli', () => {
                 const cmd = findSub(workspace, 'open');
 
                 it('should have expected options', () => {
-                    expect(optionLongs(cmd)).to.include.members(['--dir', '--verbose']);
+                    expect(optionLongs(cmd)).toEqual(expect.arrayContaining(['--dir', '--verbose']));
                 });
             });
         });
@@ -317,12 +312,12 @@ describe('cli', () => {
                     const cmd = createSubrepoCommand(repoName);
 
                     it('should have common subcommands', () => {
-                        expect(subcommandNames(cmd)).to.include.members(['clone', 'switch', 'build', 'pwd', 'log', 'run']);
+                        expect(subcommandNames(cmd)).toEqual(expect.arrayContaining(['clone', 'switch', 'build', 'pwd', 'log', 'run']));
                     });
 
                     if (SHORT_ALIASES[repoName]) {
                         it(`should have alias "${SHORT_ALIASES[repoName]}"`, () => {
-                            expect(cmd.alias()).to.equal(SHORT_ALIASES[repoName]);
+                            expect(cmd.alias()).toBe(SHORT_ALIASES[repoName]);
                         });
                     }
 
@@ -330,22 +325,17 @@ describe('cli', () => {
                         const clone = findSub(cmd, 'clone');
 
                         it('should have expected options', () => {
-                            expect(optionLongs(clone)).to.include.members([
-                                '--dir',
-                                '--protocol',
-                                '--branch',
-                                '--fork',
-                                '--override',
-                                '--verbose'
-                            ]);
+                            expect(optionLongs(clone)).toEqual(
+                                expect.arrayContaining(['--dir', '--protocol', '--branch', '--fork', '--override', '--verbose'])
+                            );
                         });
 
                         it('should restrict --protocol choices', () => {
-                            expect(choices(clone, '--protocol')).to.deep.equal(['ssh', 'https', 'gh']);
+                            expect(choices(clone, '--protocol')).toEqual(['ssh', 'https', 'gh']);
                         });
 
                         it('should restrict --override choices', () => {
-                            expect(choices(clone, '--override')).to.deep.equal(['rename', 'remove']);
+                            expect(choices(clone, '--override')).toEqual(['rename', 'remove']);
                         });
                     });
 
@@ -353,7 +343,7 @@ describe('cli', () => {
                         const sw = findSub(cmd, 'switch');
 
                         it('should have expected options', () => {
-                            expect(optionLongs(sw)).to.include.members(['--branch', '--dir', '--pr', '--force', '--verbose']);
+                            expect(optionLongs(sw)).toEqual(expect.arrayContaining(['--branch', '--dir', '--pr', '--force', '--verbose']));
                         });
                     });
 
@@ -361,12 +351,12 @@ describe('cli', () => {
                         const build = findSub(cmd, 'build');
 
                         it('should have expected options', () => {
-                            expect(optionLongs(build)).to.include.members(['--dir', '--verbose']);
+                            expect(optionLongs(build)).toEqual(expect.arrayContaining(['--dir', '--verbose']));
                         });
 
                         if (repoName === 'glsp-theia-integration') {
                             it('should have --electron option', () => {
-                                expect(optionLongs(build)).to.include('--electron');
+                                expect(optionLongs(build)).toContain('--electron');
                             });
                         }
                     });
@@ -375,7 +365,7 @@ describe('cli', () => {
                         const pwd = findSub(cmd, 'pwd');
 
                         it('should have expected options', () => {
-                            expect(optionLongs(pwd)).to.include.members(['--dir', '--verbose']);
+                            expect(optionLongs(pwd)).toEqual(expect.arrayContaining(['--dir', '--verbose']));
                         });
                     });
 
@@ -383,7 +373,7 @@ describe('cli', () => {
                         const log = findSub(cmd, 'log');
 
                         it('should have expected options', () => {
-                            expect(optionLongs(log)).to.include.members(['--dir', '--verbose']);
+                            expect(optionLongs(log)).toEqual(expect.arrayContaining(['--dir', '--verbose']));
                         });
                     });
 
@@ -391,13 +381,13 @@ describe('cli', () => {
                         const run = findSub(cmd, 'run');
 
                         it('should accept a required <script> argument', () => {
-                            expect(run.registeredArguments).to.have.lengthOf(1);
-                            expect(run.registeredArguments[0].name()).to.equal('script');
-                            expect(run.registeredArguments[0].required).to.be.true;
+                            expect(run.registeredArguments).toHaveLength(1);
+                            expect(run.registeredArguments[0].name()).toBe('script');
+                            expect(run.registeredArguments[0].required).toBe(true);
                         });
 
                         it('should have expected options', () => {
-                            expect(optionLongs(run)).to.include.members(['--dir', '--verbose']);
+                            expect(optionLongs(run)).toEqual(expect.arrayContaining(['--dir', '--verbose']));
                         });
                     });
                 });
@@ -410,11 +400,11 @@ describe('cli', () => {
                 const start = findSub(cmd, 'start');
 
                 it('should have start command', () => {
-                    expect(subcommandNames(cmd)).to.include('start');
+                    expect(subcommandNames(cmd)).toContain('start');
                 });
 
                 it('should have expected start options', () => {
-                    expect(optionLongs(start)).to.include.members(['--dir', '--browser', '--dry-run', '--verbose']);
+                    expect(optionLongs(start)).toEqual(expect.arrayContaining(['--dir', '--browser', '--dry-run', '--verbose']));
                 });
             });
 
@@ -423,29 +413,29 @@ describe('cli', () => {
                 const start = findSub(cmd, 'start');
 
                 it('should have start command', () => {
-                    expect(subcommandNames(cmd)).to.include('start');
+                    expect(subcommandNames(cmd)).toContain('start');
                 });
 
                 it('should have expected start options', () => {
-                    expect(optionLongs(start)).to.include.members(['--dir', '--socket', '--dry-run', '--verbose']);
+                    expect(optionLongs(start)).toEqual(expect.arrayContaining(['--dir', '--socket', '--dry-run', '--verbose']));
                 });
 
                 it('should have browser-bundle command', () => {
-                    expect(subcommandNames(cmd)).to.include('browser-bundle');
+                    expect(subcommandNames(cmd)).toContain('browser-bundle');
                 });
 
                 it('should have expected browser-bundle options', () => {
                     const browserBundle = findSub(cmd, 'browser-bundle');
-                    expect(optionLongs(browserBundle)).to.include.members(['--dir', '--verbose']);
+                    expect(optionLongs(browserBundle)).toEqual(expect.arrayContaining(['--dir', '--verbose']));
                 });
 
                 it('should have node-bundle command', () => {
-                    expect(subcommandNames(cmd)).to.include('node-bundle');
+                    expect(subcommandNames(cmd)).toContain('node-bundle');
                 });
 
                 it('should have expected node-bundle options', () => {
                     const nodeBundle = findSub(cmd, 'node-bundle');
-                    expect(optionLongs(nodeBundle)).to.include.members(['--dir', '--verbose']);
+                    expect(optionLongs(nodeBundle)).toEqual(expect.arrayContaining(['--dir', '--verbose']));
                 });
             });
 
@@ -454,11 +444,11 @@ describe('cli', () => {
                 const start = findSub(cmd, 'start');
 
                 it('should have start command', () => {
-                    expect(subcommandNames(cmd)).to.include('start');
+                    expect(subcommandNames(cmd)).toContain('start');
                 });
 
                 it('should have expected start options', () => {
-                    expect(optionLongs(start)).to.include.members(['--dir', '--socket', '--dry-run', '--verbose']);
+                    expect(optionLongs(start)).toEqual(expect.arrayContaining(['--dir', '--socket', '--dry-run', '--verbose']));
                 });
             });
 
@@ -466,21 +456,23 @@ describe('cli', () => {
                 const cmd = createSubrepoCommand('glsp-theia-integration');
 
                 it('should have start command', () => {
-                    expect(subcommandNames(cmd)).to.include('start');
+                    expect(subcommandNames(cmd)).toContain('start');
                 });
 
                 it('should have expected start options', () => {
                     const start = findSub(cmd, 'start');
-                    expect(optionLongs(start)).to.include.members(['--dir', '--electron', '--debug', '--dry-run', '--verbose']);
+                    expect(optionLongs(start)).toEqual(
+                        expect.arrayContaining(['--dir', '--electron', '--debug', '--dry-run', '--verbose'])
+                    );
                 });
 
                 it('should have open command', () => {
-                    expect(subcommandNames(cmd)).to.include('open');
+                    expect(subcommandNames(cmd)).toContain('open');
                 });
 
                 it('should have expected open options', () => {
                     const open = findSub(cmd, 'open');
-                    expect(optionLongs(open)).to.include.members(['--verbose']);
+                    expect(optionLongs(open)).toEqual(expect.arrayContaining(['--verbose']));
                 });
             });
 
@@ -488,47 +480,47 @@ describe('cli', () => {
                 const cmd = createSubrepoCommand('glsp-vscode-integration');
 
                 it('should have vsix-id command', () => {
-                    expect(subcommandNames(cmd)).to.include('vsix-id');
+                    expect(subcommandNames(cmd)).toContain('vsix-id');
                 });
 
                 it('should have vsix-path command', () => {
-                    expect(subcommandNames(cmd)).to.include('vsix-path');
+                    expect(subcommandNames(cmd)).toContain('vsix-path');
                 });
 
                 it('should have expected vsix-path options', () => {
                     const vsixPath = findSub(cmd, 'vsix-path');
-                    expect(optionLongs(vsixPath)).to.include.members(['--dir', '--verbose']);
+                    expect(optionLongs(vsixPath)).toEqual(expect.arrayContaining(['--dir', '--verbose']));
                 });
 
                 it('should have package command', () => {
-                    expect(subcommandNames(cmd)).to.include('package');
+                    expect(subcommandNames(cmd)).toContain('package');
                 });
 
                 it('should have expected package options', () => {
                     const pkg = findSub(cmd, 'package');
-                    expect(optionLongs(pkg)).to.include.members(['--dir', '--verbose']);
+                    expect(optionLongs(pkg)).toEqual(expect.arrayContaining(['--dir', '--verbose']));
                 });
 
                 it('should have web-vsix-id command', () => {
-                    expect(subcommandNames(cmd)).to.include('web-vsix-id');
+                    expect(subcommandNames(cmd)).toContain('web-vsix-id');
                 });
 
                 it('should have web-vsix-path command', () => {
-                    expect(subcommandNames(cmd)).to.include('web-vsix-path');
+                    expect(subcommandNames(cmd)).toContain('web-vsix-path');
                 });
 
                 it('should have expected web-vsix-path options', () => {
                     const webVsixPath = findSub(cmd, 'web-vsix-path');
-                    expect(optionLongs(webVsixPath)).to.include.members(['--dir', '--verbose']);
+                    expect(optionLongs(webVsixPath)).toEqual(expect.arrayContaining(['--dir', '--verbose']));
                 });
 
                 it('should have web-package command', () => {
-                    expect(subcommandNames(cmd)).to.include('web-package');
+                    expect(subcommandNames(cmd)).toContain('web-package');
                 });
 
                 it('should have expected web-package options', () => {
                     const webPkg = findSub(cmd, 'web-package');
-                    expect(optionLongs(webPkg)).to.include.members(['--dir', '--verbose']);
+                    expect(optionLongs(webPkg)).toEqual(expect.arrayContaining(['--dir', '--verbose']));
                 });
             });
         });
diff --git a/dev-packages/cli/src/commands/releng/common.spec.ts b/dev-packages/cli/src/commands/releng/common.spec.ts
index 88c9925..f31af98 100644
--- a/dev-packages/cli/src/commands/releng/common.spec.ts
+++ b/dev-packages/cli/src/commands/releng/common.spec.ts
@@ -45,19 +45,19 @@ describe('common', () => {
         it('should derive repo name from HTTPS remote URL', () => {
             vi.spyOn(gitUtil, 'getRemoteUrl').mockReturnValue('https://github.com/eclipse-glsp/glsp-client.git');
             const result = GLSPRepo.deriveFromDirectory('/some/path');
-            expect(result).to.equal('glsp-client');
+            expect(result).toBe('glsp-client');
         });
 
         it('should derive repo name from SSH remote URL', () => {
             vi.spyOn(gitUtil, 'getRemoteUrl').mockReturnValue('git@github.com:eclipse-glsp/glsp-server-node.git');
             const result = GLSPRepo.deriveFromDirectory('/some/path');
-            expect(result).to.equal('glsp-server-node');
+            expect(result).toBe('glsp-server-node');
         });
 
         it('should return undefined for a non-GLSP repository', () => {
             vi.spyOn(gitUtil, 'getRemoteUrl').mockReturnValue('https://github.com/other/repo.git');
             const result = GLSPRepo.deriveFromDirectory('/some/path');
-            expect(result).to.be.undefined;
+            expect(result).toBeUndefined();
         });
     });
 
@@ -65,7 +65,7 @@ describe('common', () => {
         it('should return true when gh is installed and authenticated', () => {
             vi.spyOn(processUtil, 'exec').mockReturnValue('');
             const result = isGithubCLIAuthenticated();
-            expect(result).to.be.true;
+            expect(result).toBe(true);
         });
 
         it('should return false when gh auth status throws', () => {
@@ -76,7 +76,7 @@ describe('common', () => {
                 return '';
             });
             const result = isGithubCLIAuthenticated();
-            expect(result).to.be.false;
+            expect(result).toBe(false);
         });
 
         it('should return false when gh is not installed', () => {
@@ -84,7 +84,7 @@ describe('common', () => {
                 throw new Error('gh not found');
             });
             const result = isGithubCLIAuthenticated();
-            expect(result).to.be.false;
+            expect(result).toBe(false);
         });
     });
 
@@ -106,7 +106,7 @@ describe('common', () => {
             } as unknown as PackageHelper;
 
             const result = getGLSPDependencies(pkg);
-            expect(result).to.deep.equal(['@eclipse-glsp/client', '@eclipse-glsp/config']);
+            expect(result).toEqual(['@eclipse-glsp/client', '@eclipse-glsp/config']);
         });
 
         it('should return empty array when dependency sections are missing', () => {
@@ -118,41 +118,41 @@ describe('common', () => {
             } as unknown as PackageHelper;
 
             const result = getGLSPDependencies(pkg);
-            expect(result).to.deep.equal([]);
+            expect(result).toEqual([]);
         });
     });
 
     describe('isNextVersion', () => {
         it('should return true for -next suffix', () => {
-            expect(isNextVersion('1.0.0-next')).to.be.true;
+            expect(isNextVersion('1.0.0-next')).toBe(true);
         });
 
         it('should return true for .SNAPSHOT suffix', () => {
-            expect(isNextVersion('1.0.0.SNAPSHOT')).to.be.true;
+            expect(isNextVersion('1.0.0.SNAPSHOT')).toBe(true);
         });
 
         it('should return false for a release version', () => {
-            expect(isNextVersion('1.0.0')).to.be.false;
+            expect(isNextVersion('1.0.0')).toBe(false);
         });
     });
 
     describe('asMvnVersion', () => {
         it('should convert -next to -SNAPSHOT', () => {
-            expect(asMvnVersion('1.0.0-next')).to.equal('1.0.0-SNAPSHOT');
+            expect(asMvnVersion('1.0.0-next')).toBe('1.0.0-SNAPSHOT');
         });
 
         it('should return release versions unchanged', () => {
-            expect(asMvnVersion('2.3.1')).to.equal('2.3.1');
+            expect(asMvnVersion('2.3.1')).toBe('2.3.1');
         });
     });
 
     describe('VersionType.validate', () => {
         it('should throw when type is custom but no version is provided', () => {
-            expect(() => VersionType.validate('custom')).to.throw(/Custom version must be provided/);
+            expect(() => VersionType.validate('custom')).toThrow(/Custom version must be provided/);
         });
 
         it('should accept custom type with a version', () => {
-            expect(() => VersionType.validate('custom', '1.0.0')).to.not.throw();
+            expect(() => VersionType.validate('custom', '1.0.0')).not.toThrow();
         });
 
         it('should warn when a custom version is provided for non-custom type', () => {
@@ -162,7 +162,7 @@ describe('common', () => {
         });
 
         it('should accept non-custom type without a version', () => {
-            expect(() => VersionType.validate('minor')).to.not.throw();
+            expect(() => VersionType.validate('minor')).not.toThrow();
         });
     });
 
@@ -170,50 +170,50 @@ describe('common', () => {
         it('should return the custom version for npm repos', () => {
             const options = { versionType: 'custom' as VersionType, repoDir: '/repo', repo: 'glsp-client' as const, verbose: false };
             const result = VersionType.deriveVersion(options, '99.0.0');
-            expect(result).to.equal('99.0.0');
+            expect(result).toBe('99.0.0');
         });
 
         it('should throw for invalid custom version on npm repos', () => {
             const options = { versionType: 'custom' as VersionType, repoDir: '/repo', repo: 'glsp-client' as const, verbose: false };
-            expect(() => VersionType.deriveVersion(options, 'not-semver')).to.throw(/Not a valid custom version/);
+            expect(() => VersionType.deriveVersion(options, 'not-semver')).toThrow(/Not a valid custom version/);
         });
 
         it('should accept any custom version for java repos', () => {
             const options = { versionType: 'custom' as VersionType, repoDir: '/repo', repo: 'glsp-server' as const, verbose: false };
             const result = VersionType.deriveVersion(options, '2.0.0.qualifier');
-            expect(result).to.equal('2.0.0.qualifier');
+            expect(result).toBe('2.0.0.qualifier');
         });
 
         it('should derive minor version from local package', () => {
             vi.spyOn(packageUtil, 'readPackage').mockReturnValue({ content: { version: '1.2.0' } } as unknown as PackageHelper);
             const options = { versionType: 'minor' as VersionType, repoDir: '/repo', repo: 'glsp-client' as const, verbose: false };
             const result = VersionType.deriveVersion(options);
-            expect(result).to.equal('1.3.0');
+            expect(result).toBe('1.3.0');
         });
 
         it('should derive next version with -next suffix', () => {
             vi.spyOn(packageUtil, 'readPackage').mockReturnValue({ content: { version: '1.2.0' } } as unknown as PackageHelper);
             const options = { versionType: 'next' as VersionType, repoDir: '/repo', repo: 'glsp-client' as const, verbose: false };
             const result = VersionType.deriveVersion(options);
-            expect(result).to.equal('1.3.0-next');
+            expect(result).toBe('1.3.0-next');
         });
     });
 
     describe('getLocalVersion', () => {
         it('should read from pom.xml for glsp-server', () => {
             vi.spyOn(fileUtil, 'readFile').mockReturnValue('<version>2.0.0</version>');
-            expect(getLocalVersion('/repo', 'glsp-server')).to.equal('2.0.0');
+            expect(getLocalVersion('/repo', 'glsp-server')).toBe('2.0.0');
         });
 
         it('should read from server/pom.xml for glsp-eclipse-integration', () => {
             const readStub = vi.spyOn(fileUtil, 'readFile').mockReturnValue('<version>2.1.0</version>');
-            expect(getLocalVersion('/repo', 'glsp-eclipse-integration')).to.equal('2.1.0');
-            expect(readStub.mock.calls[0][0]).to.contain('server');
+            expect(getLocalVersion('/repo', 'glsp-eclipse-integration')).toBe('2.1.0');
+            expect(readStub.mock.calls[0][0]).toContain('server');
         });
 
         it('should read from package.json for npm repos', () => {
             vi.spyOn(packageUtil, 'readPackage').mockReturnValue({ content: { version: '1.5.0' } } as unknown as PackageHelper);
-            expect(getLocalVersion('/repo', 'glsp-client')).to.equal('1.5.0');
+            expect(getLocalVersion('/repo', 'glsp-client')).toBe('1.5.0');
         });
     });
 
@@ -226,46 +226,46 @@ describe('common', () => {
   <version>2.7.0-SNAPSHOT</version>
 </project>`
             );
-            expect(getVersionFromPom('/repo')).to.equal('2.7.0-SNAPSHOT');
+            expect(getVersionFromPom('/repo')).toBe('2.7.0-SNAPSHOT');
         });
 
         it('should throw when no version is found', () => {
             vi.spyOn(fileUtil, 'readFile').mockReturnValue('<project></project>');
-            expect(() => getVersionFromPom('/repo')).to.throw(/Could not find version/);
+            expect(() => getVersionFromPom('/repo')).toThrow(/Could not find version/);
         });
     });
 
     describe('getVersionFromPackage', () => {
         it('should return the version from package.json', () => {
             vi.spyOn(packageUtil, 'readPackage').mockReturnValue({ content: { version: '1.0.0' } } as unknown as PackageHelper);
-            expect(getVersionFromPackage('/repo')).to.equal('1.0.0');
+            expect(getVersionFromPackage('/repo')).toBe('1.0.0');
         });
 
         it('should throw when no version is found', () => {
             vi.spyOn(packageUtil, 'readPackage').mockReturnValue({ content: {} } as unknown as PackageHelper);
-            expect(() => getVersionFromPackage('/repo')).to.throw(/No version found/);
+            expect(() => getVersionFromPackage('/repo')).toThrow(/No version found/);
         });
     });
 
     describe('getLastReleaseTag', () => {
         it('should return the first valid semver tag starting with v', () => {
             vi.spyOn(processUtil, 'exec').mockReturnValue('v2.0.0\nv1.0.0\nsome-tag');
-            expect(getLastReleaseTag('/repo')).to.equal('v2.0.0');
+            expect(getLastReleaseTag('/repo')).toBe('v2.0.0');
         });
 
         it('should skip pre-release tags', () => {
             vi.spyOn(processUtil, 'exec').mockReturnValue('v2.0.0-rc.1\nv1.0.0');
-            expect(getLastReleaseTag('/repo')).to.equal('v1.0.0');
+            expect(getLastReleaseTag('/repo')).toBe('v1.0.0');
         });
 
         it('should skip tags without v prefix', () => {
             vi.spyOn(processUtil, 'exec').mockReturnValue('release-1.0\nv0.9.0');
-            expect(getLastReleaseTag('/repo')).to.equal('v0.9.0');
+            expect(getLastReleaseTag('/repo')).toBe('v0.9.0');
         });
 
         it('should return undefined when no valid tag exists', () => {
             vi.spyOn(processUtil, 'exec').mockReturnValue('nightly\nsome-tag');
-            expect(getLastReleaseTag('/repo')).to.be.undefined;
+            expect(getLastReleaseTag('/repo')).toBeUndefined();
         });
     });
 
@@ -289,23 +289,23 @@ describe('common', () => {
             vi.spyOn(fileUtil, 'readFile').mockReturnValue(changelogContent);
             vi.spyOn(processUtil, 'exec').mockReturnValue('v1.0.0');
             const result = getChangeLogChanges({ repoDir: '/repo', version: '2.0.0', repo: 'glsp-client' });
-            expect(result).to.contain('Added feature A');
-            expect(result).to.contain('Added feature B');
-            expect(result).to.not.contain('Initial release');
+            expect(result).toContain('Added feature A');
+            expect(result).toContain('Added feature B');
+            expect(result).not.toContain('Initial release');
         });
 
         it('should append a full changelog link when a previous tag exists', () => {
             vi.spyOn(fileUtil, 'readFile').mockReturnValue(changelogContent);
             vi.spyOn(processUtil, 'exec').mockReturnValue('v1.0.0');
             const result = getChangeLogChanges({ repoDir: '/repo', version: '2.0.0', repo: 'glsp-client' });
-            expect(result).to.contain('Full Changelog');
-            expect(result).to.contain('v1.0.0...v2.0.0');
+            expect(result).toContain('Full Changelog');
+            expect(result).toContain('v1.0.0...v2.0.0');
         });
 
         it('should throw when no section matches the version', () => {
             vi.spyOn(fileUtil, 'readFile').mockReturnValue(changelogContent);
             vi.spyOn(processUtil, 'exec').mockReturnValue('');
-            expect(() => getChangeLogChanges({ repoDir: '/repo', version: '9.9.9', repo: 'glsp-client' })).to.throw(
+            expect(() => getChangeLogChanges({ repoDir: '/repo', version: '9.9.9', repo: 'glsp-client' })).toThrow(
                 /No changelog section found/
             );
         });
@@ -314,8 +314,8 @@ describe('common', () => {
             vi.spyOn(fileUtil, 'readFile').mockReturnValue(changelogContent);
             vi.spyOn(processUtil, 'exec').mockReturnValue('');
             const result = getChangeLogChanges({ repoDir: '/repo', version: '2.0.0', repo: 'glsp-client' });
-            expect(result).to.contain('## Features');
-            expect(result).to.not.contain('### Features');
+            expect(result).toContain('## Features');
+            expect(result).not.toContain('### Features');
         });
     });
 });
diff --git a/dev-packages/cli/src/commands/releng/publish.spec.ts b/dev-packages/cli/src/commands/releng/publish.spec.ts
index 4a38524..6c6b334 100644
--- a/dev-packages/cli/src/commands/releng/publish.spec.ts
+++ b/dev-packages/cli/src/commands/releng/publish.spec.ts
@@ -73,7 +73,7 @@ describe('releng publish', () => {
             createRootPackage('2.8.0-next');
             stubGit('v2.7.0', '42');
             const canary = deriveCanaryVersion(tempDir);
-            expect(canary).to.deep.equal({ base: '2.8.0-next', lastTag: 'v2.7.0', commitCount: 42, version: '2.8.0-next.42' });
+            expect(canary).toEqual({ base: '2.8.0-next', lastTag: 'v2.7.0', commitCount: 42, version: '2.8.0-next.42' });
         });
 
         it('should throw a helpful error when no git tag can be found', () => {
@@ -84,7 +84,7 @@ describe('releng publish', () => {
                 }
                 return undefined;
             });
-            expect(() => deriveCanaryVersion(tempDir)).to.throw(/fetch-depth: 0/);
+            expect(() => deriveCanaryVersion(tempDir)).toThrow(/fetch-depth: 0/);
         });
     });
 
@@ -100,15 +100,15 @@ describe('releng publish', () => {
 
             const writtenA = JSON.parse(fs.readFileSync(pkgA.filePath, 'utf8'));
             const writtenB = JSON.parse(fs.readFileSync(pkgB.filePath, 'utf8'));
-            expect(writtenA.version).to.equal('2.8.0-next.42');
-            expect(writtenB.version).to.equal('2.8.0-next.42');
+            expect(writtenA.version).toBe('2.8.0-next.42');
+            expect(writtenB.version).toBe('2.8.0-next.42');
             // the root package keeps the plain base version
             const root = JSON.parse(fs.readFileSync(path.join(tempDir, 'package.json'), 'utf8'));
-            expect(root.version).to.equal('2.8.0-next');
+            expect(root.version).toBe('2.8.0-next');
 
             expect(execAsyncStub).toHaveBeenCalledOnce();
-            expect(execAsyncStub.mock.calls[0][0]).to.equal('pnpm publish -r --tag next --no-git-checks --report-summary');
-            expect(execAsyncStub.mock.calls[0][1].cwd).to.equal(tempDir);
+            expect(execAsyncStub.mock.calls[0][0]).toBe('pnpm publish -r --tag next --no-git-checks --report-summary');
+            expect(execAsyncStub.mock.calls[0][1].cwd).toBe(tempDir);
         });
 
         it('should not write versions and pass --dry-run in dry-run mode', async () => {
@@ -120,8 +120,8 @@ describe('releng publish', () => {
             await publish('next', makeOptions({ dryRun: true }));
 
             const writtenA = JSON.parse(fs.readFileSync(pkgA.filePath, 'utf8'));
-            expect(writtenA.version).to.equal('2.8.0-next');
-            expect(execAsyncStub.mock.calls[0][0]).to.contain('--dry-run');
+            expect(writtenA.version).toBe('2.8.0-next');
+            expect(execAsyncStub.mock.calls[0][0]).toContain('--dry-run');
         });
 
         it('should pass a custom registry to pnpm publish', async () => {
@@ -131,7 +131,7 @@ describe('releng publish', () => {
 
             await publish('next', makeOptions({ registry: 'http://localhost:4873' }));
 
-            expect(execAsyncStub.mock.calls[0][0]).to.contain('--registry http://localhost:4873');
+            expect(execAsyncStub.mock.calls[0][0]).toContain('--registry http://localhost:4873');
         });
 
         it('should bump versions and print the publish command without publishing in interactive mode', async () => {
@@ -144,10 +144,10 @@ describe('releng publish', () => {
             await publish('next', makeOptions({ interactive: true }));
 
             // versions are still bumped on disk
-            expect(JSON.parse(fs.readFileSync(pkgA.filePath, 'utf8')).version).to.equal('2.8.0-next.42');
+            expect(JSON.parse(fs.readFileSync(pkgA.filePath, 'utf8')).version).toBe('2.8.0-next.42');
             // but nothing is published
             expect(execAsyncStub).not.toHaveBeenCalled();
-            expect(infoStub.mock.calls.flat()).to.contain('\n  pnpm publish -r --tag next --no-git-checks\n');
+            expect(infoStub.mock.calls.flat()).toContain('\n  pnpm publish -r --tag next --no-git-checks\n');
         });
 
         it('should refuse to publish a canary if the root version is not a next version', async () => {
@@ -157,7 +157,7 @@ describe('releng publish', () => {
                 await publish('next', makeOptions());
                 expect.fail('should have thrown');
             } catch (error) {
-                expect((error as Error).message).to.contain('not a next version');
+                expect((error as Error).message).toContain('not a next version');
             }
         });
     });
@@ -169,7 +169,7 @@ describe('releng publish', () => {
                 await publish('latest', makeOptions());
                 expect.fail('should have thrown');
             } catch (error) {
-                expect((error as Error).message).to.contain("Refusing to publish under the 'latest' dist-tag");
+                expect((error as Error).message).toContain("Refusing to publish under the 'latest' dist-tag");
             }
         });
 
@@ -188,7 +188,7 @@ describe('releng publish', () => {
             await publish('latest', makeOptions());
 
             expect(execAsyncStub).toHaveBeenCalledOnce();
-            expect(execAsyncStub.mock.calls[0][0]).to.equal('pnpm publish -r --tag latest --no-git-checks --report-summary');
+            expect(execAsyncStub.mock.calls[0][0]).toBe('pnpm publish -r --tag latest --no-git-checks --report-summary');
         });
 
         it('should skip publishing when all package versions already exist', async () => {
@@ -243,7 +243,7 @@ describe('releng publish', () => {
 
             await publish('next', makeOptions());
 
-            expect(fs.existsSync(summaryPath)).to.be.false;
+            expect(fs.existsSync(summaryPath)).toBe(false);
         });
     });
 });
diff --git a/dev-packages/cli/src/commands/releng/version.spec.ts b/dev-packages/cli/src/commands/releng/version.spec.ts
index 5f50899..dd60be8 100644
--- a/dev-packages/cli/src/commands/releng/version.spec.ts
+++ b/dev-packages/cli/src/commands/releng/version.spec.ts
@@ -65,8 +65,8 @@ describe('releng version', () => {
 
         await setVersion(makeOptions('2.9.0', [pkgA, root]));
 
-        expect(readPackageJson('.').version).to.equal('2.9.0');
-        expect(readPackageJson('packages/a').version).to.equal('2.9.0');
+        expect(readPackageJson('.').version).toBe('2.9.0');
+        expect(readPackageJson('packages/a').version).toBe('2.9.0');
     });
 
     it('should preserve workspace: dependency ranges', async () => {
@@ -79,8 +79,8 @@ describe('releng version', () => {
 
         await setVersion(makeOptions('2.9.0', [pkgA, pkgB, root]));
 
-        expect(readPackageJson('packages/b').dependencies!['@eclipse-glsp/a']).to.equal('workspace:*');
-        expect(readPackageJson('packages/b').version).to.equal('2.9.0');
+        expect(readPackageJson('packages/b').dependencies!['@eclipse-glsp/a']).toBe('workspace:*');
+        expect(readPackageJson('packages/b').version).toBe('2.9.0');
     });
 
     it('should bump exact-pinned workspace dependencies to the new version', async () => {
@@ -93,7 +93,7 @@ describe('releng version', () => {
 
         await setVersion(makeOptions('2.9.0-next', [pkgA, pkgB, root]));
 
-        expect(readPackageJson('packages/b').dependencies!['@eclipse-glsp/a']).to.equal('2.9.0-next');
+        expect(readPackageJson('packages/b').dependencies!['@eclipse-glsp/a']).toBe('2.9.0-next');
     });
 
     it("should set external @eclipse-glsp dependencies to 'next' for next versions", async () => {
@@ -105,7 +105,7 @@ describe('releng version', () => {
 
         await setVersion(makeOptions('2.9.0-next', [pkgA, root]));
 
-        expect(readPackageJson('packages/a').dependencies!['@eclipse-glsp/protocol']).to.equal('next');
+        expect(readPackageJson('packages/a').dependencies!['@eclipse-glsp/protocol']).toBe('next');
     });
 
     it('should bump external @eclipse-glsp dependencies to the release version for release versions', async () => {
@@ -117,6 +117,6 @@ describe('releng version', () => {
 
         await setVersion(makeOptions('2.9.0', [pkgA, root]));
 
-        expect(readPackageJson('packages/a').dependencies!['@eclipse-glsp/protocol']).to.equal('2.9.0');
+        expect(readPackageJson('packages/a').dependencies!['@eclipse-glsp/protocol']).toBe('2.9.0');
     });
 });
diff --git a/dev-packages/cli/src/commands/repo/build.spec.ts b/dev-packages/cli/src/commands/repo/build.spec.ts
index d26e228..e582d41 100644
--- a/dev-packages/cli/src/commands/repo/build.spec.ts
+++ b/dev-packages/cli/src/commands/repo/build.spec.ts
@@ -56,43 +56,43 @@ describe('build-action', () => {
             createRepoDirs('glsp-client');
             await buildSingleRepo('glsp-client', makeOptions());
             expect(execAsyncStub).toHaveBeenCalledTimes(2);
-            expect(execAsyncStub.mock.calls[0][0]).to.equal('pnpm install');
-            expect(execAsyncStub.mock.calls[1][0]).to.equal('pnpm run --if-present build');
+            expect(execAsyncStub.mock.calls[0][0]).toBe('pnpm install');
+            expect(execAsyncStub.mock.calls[1][0]).toBe('pnpm run --if-present build');
         });
 
         it('should run pnpm install, build and browser build for theia-integration', async () => {
             createRepoDirs('glsp-theia-integration');
             await buildSingleRepo('glsp-theia-integration', makeOptions());
             expect(execAsyncStub).toHaveBeenCalledTimes(3);
-            expect(execAsyncStub.mock.calls[0][0]).to.equal('pnpm install');
-            expect(execAsyncStub.mock.calls[1][0]).to.equal('pnpm run --if-present build');
-            expect(execAsyncStub.mock.calls[2][0]).to.equal('pnpm run browser build');
+            expect(execAsyncStub.mock.calls[0][0]).toBe('pnpm install');
+            expect(execAsyncStub.mock.calls[1][0]).toBe('pnpm run --if-present build');
+            expect(execAsyncStub.mock.calls[2][0]).toBe('pnpm run browser build');
         });
 
         it('should run electron build with --electron', async () => {
             createRepoDirs('glsp-theia-integration');
             await buildSingleRepo('glsp-theia-integration', makeOptions({ electron: true }));
             expect(execAsyncStub).toHaveBeenCalledTimes(3);
-            expect(execAsyncStub.mock.calls[2][0]).to.equal('pnpm run electron build');
+            expect(execAsyncStub.mock.calls[2][0]).toBe('pnpm run electron build');
         });
 
         it('should run mvn for glsp-server', async () => {
             createRepoDirs('glsp-server');
             await buildSingleRepo('glsp-server', makeOptions());
             expect(execAsyncStub).toHaveBeenCalledOnce();
-            expect(execAsyncStub.mock.calls[0][0]).to.equal('mvn clean verify -Pm2 -Pfatjar -Dstyle.color=always -B');
+            expect(execAsyncStub.mock.calls[0][0]).toBe('mvn clean verify -Pm2 -Pfatjar -Dstyle.color=always -B');
         });
 
         it('should build client and server for eclipse-integration', async () => {
             createRepoDirs(path.join('glsp-eclipse-integration', 'client'));
             await buildSingleRepo('glsp-eclipse-integration', makeOptions());
             expect(execAsyncStub).toHaveBeenCalledTimes(3);
-            expect(execAsyncStub.mock.calls[0][0]).to.equal('pnpm install');
-            expect(execAsyncStub.mock.calls[0][1].cwd).to.contain(path.join('glsp-eclipse-integration', 'client'));
-            expect(execAsyncStub.mock.calls[1][0]).to.equal('pnpm run --if-present build');
-            expect(execAsyncStub.mock.calls[1][1].cwd).to.contain(path.join('glsp-eclipse-integration', 'client'));
-            expect(execAsyncStub.mock.calls[2][0]).to.equal('mvn clean verify -Dstyle.color=always -B');
-            expect(execAsyncStub.mock.calls[2][1].cwd).to.contain(path.join('glsp-eclipse-integration', 'server'));
+            expect(execAsyncStub.mock.calls[0][0]).toBe('pnpm install');
+            expect(execAsyncStub.mock.calls[0][1].cwd).toContain(path.join('glsp-eclipse-integration', 'client'));
+            expect(execAsyncStub.mock.calls[1][0]).toBe('pnpm run --if-present build');
+            expect(execAsyncStub.mock.calls[1][1].cwd).toContain(path.join('glsp-eclipse-integration', 'client'));
+            expect(execAsyncStub.mock.calls[2][0]).toBe('mvn clean verify -Dstyle.color=always -B');
+            expect(execAsyncStub.mock.calls[2][1].cwd).toContain(path.join('glsp-eclipse-integration', 'server'));
         });
     });
 
@@ -100,7 +100,7 @@ describe('build-action', () => {
         it('should build repos sequentially in dependency order', async () => {
             createRepoDirs('glsp', 'glsp-client', 'glsp-server-node');
             const failures = await runBuildOrdered(['glsp', 'glsp-client', 'glsp-server-node'], makeOptions());
-            expect(failures).to.equal(0);
+            expect(failures).toBe(0);
             // pnpm install + build per repo
             expect(execAsyncStub).toHaveBeenCalledTimes(6);
         });
@@ -111,7 +111,7 @@ describe('build-action', () => {
                 await runBuildOrdered(['glsp', 'glsp-client'], makeOptions());
                 expect.fail('should have thrown');
             } catch (error) {
-                expect((error as Error).message).to.contain('glsp-client');
+                expect((error as Error).message).toContain('glsp-client');
             }
         });
 
@@ -119,7 +119,7 @@ describe('build-action', () => {
             createRepoDirs('glsp', 'glsp-client', 'glsp-server-node');
             execAsyncStub.mockRejectedValueOnce(new Error('build failed'));
             const failures = await runBuildOrdered(['glsp', 'glsp-client', 'glsp-server-node'], makeOptions({ failFast: true }));
-            expect(failures).to.equal(1);
+            expect(failures).toBe(1);
             expect(execAsyncStub).toHaveBeenCalledTimes(1);
         });
 
@@ -127,7 +127,7 @@ describe('build-action', () => {
             createRepoDirs('glsp', 'glsp-client', 'glsp-server-node');
             execAsyncStub.mockRejectedValueOnce(new Error('build failed'));
             const failures = await runBuildOrdered(['glsp', 'glsp-client', 'glsp-server-node'], makeOptions({ failFast: false }));
-            expect(failures).to.equal(1);
+            expect(failures).toBe(1);
             // first repo fails on install (1 call); the other two each run install + build (2+2)
             expect(execAsyncStub).toHaveBeenCalledTimes(5);
         });
diff --git a/dev-packages/cli/src/commands/repo/clone.spec.ts b/dev-packages/cli/src/commands/repo/clone.spec.ts
index 3cd1b51..be64e23 100644
--- a/dev-packages/cli/src/commands/repo/clone.spec.ts
+++ b/dev-packages/cli/src/commands/repo/clone.spec.ts
@@ -51,35 +51,35 @@ describe('clone-action', () => {
             await cloneSingleRepo('glsp-client', makeOptions());
             expect(execStub).toHaveBeenCalledOnce();
             const cmd = execStub.mock.calls[0][0] as string;
-            expect(cmd).to.contain('git clone');
-            expect(cmd).to.contain('https://github.com/eclipse-glsp/glsp-client.git');
-            expect(cmd).to.contain(path.join(tempDir, 'glsp-client'));
+            expect(cmd).toContain('git clone');
+            expect(cmd).toContain('https://github.com/eclipse-glsp/glsp-client.git');
+            expect(cmd).toContain(path.join(tempDir, 'glsp-client'));
         });
 
         it('should call git clone with ssh URL', async () => {
             await cloneSingleRepo('glsp-client', makeOptions({ protocol: 'ssh' }));
             const cmd = execStub.mock.calls[0][0] as string;
-            expect(cmd).to.contain('git@github.com:eclipse-glsp/glsp-client.git');
+            expect(cmd).toContain('git@github.com:eclipse-glsp/glsp-client.git');
         });
 
         it('should use fork org when --fork is set', async () => {
             await cloneSingleRepo('glsp-client', makeOptions({ fork: 'myuser' }));
             const cmd = execStub.mock.calls[0][0] as string;
-            expect(cmd).to.contain('myuser/glsp-client');
+            expect(cmd).toContain('myuser/glsp-client');
         });
 
         it('should add upstream remote when --fork is set', async () => {
             await cloneSingleRepo('glsp-client', makeOptions({ fork: 'myuser' }));
             const upstreamCall = execStub.mock.calls.find(c => (c[0] as string).includes('remote add upstream'));
-            expect(upstreamCall).to.exist;
-            expect(upstreamCall![0]).to.contain('eclipse-glsp/glsp-client');
+            expect(upstreamCall).toBeDefined();
+            expect(upstreamCall![0]).toContain('eclipse-glsp/glsp-client');
         });
 
         it('should not add upstream if already present after clone', async () => {
             vi.spyOn(forkUtils, 'getRemotes').mockReturnValue({ upstream: 'https://github.com/eclipse-glsp/glsp-client.git' });
             await cloneSingleRepo('glsp-client', makeOptions({ fork: 'myuser' }));
             const upstreamCall = execStub.mock.calls.find(c => (c[0] as string).includes('remote add upstream'));
-            expect(upstreamCall).to.be.undefined;
+            expect(upstreamCall).toBeUndefined();
         });
 
         it('should call ensureFork when --fork is set', async () => {
@@ -95,13 +95,13 @@ describe('clone-action', () => {
         it('should include -b flag when --branch is set', async () => {
             await cloneSingleRepo('glsp-client', makeOptions({ branch: 'release/2.0' }));
             const cmd = execStub.mock.calls[0][0] as string;
-            expect(cmd).to.contain('-b release/2.0');
+            expect(cmd).toContain('-b release/2.0');
         });
 
         it('should skip when target directory exists and no --override', async () => {
             fs.mkdirSync(path.join(tempDir, 'glsp-client'));
             const result = await cloneSingleRepo('glsp-client', makeOptions());
-            expect(result).to.be.false;
+            expect(result).toBe(false);
             expect(execStub).not.toHaveBeenCalled();
         });
 
@@ -110,7 +110,7 @@ describe('clone-action', () => {
             fs.mkdirSync(targetDir);
             fs.writeFileSync(path.join(targetDir, 'old.txt'), 'old');
             await cloneSingleRepo('glsp-client', makeOptions({ override: 'remove' }));
-            expect(fs.existsSync(path.join(targetDir, 'old.txt'))).to.be.false;
+            expect(fs.existsSync(path.join(targetDir, 'old.txt'))).toBe(false);
             expect(execStub).toHaveBeenCalledOnce();
         });
 
@@ -120,15 +120,15 @@ describe('clone-action', () => {
             fs.writeFileSync(path.join(targetDir, 'marker.txt'), 'original');
             await cloneSingleRepo('glsp-client', makeOptions({ override: 'rename' }));
             const entries = fs.readdirSync(tempDir).filter(e => e.startsWith('glsp-client_'));
-            expect(entries).to.have.lengthOf(1);
-            expect(fs.readFileSync(path.join(tempDir, entries[0], 'marker.txt'), 'utf-8')).to.equal('original');
+            expect(entries).toHaveLength(1);
+            expect(fs.readFileSync(path.join(tempDir, entries[0], 'marker.txt'), 'utf-8')).toBe('original');
         });
 
         it('should use gh repo clone for gh protocol', async () => {
             await cloneSingleRepo('glsp-client', makeOptions({ protocol: 'gh' }));
             const cmd = execStub.mock.calls[0][0] as string;
-            expect(cmd).to.contain('gh repo clone');
-            expect(cmd).to.contain('eclipse-glsp/glsp-client');
+            expect(cmd).toContain('gh repo clone');
+            expect(cmd).toContain('eclipse-glsp/glsp-client');
         });
     });
 });
diff --git a/dev-packages/cli/src/commands/repo/common/utils.spec.ts b/dev-packages/cli/src/commands/repo/common/utils.spec.ts
index d76e991..e5e5bbb 100644
--- a/dev-packages/cli/src/commands/repo/common/utils.spec.ts
+++ b/dev-packages/cli/src/commands/repo/common/utils.spec.ts
@@ -42,20 +42,20 @@ describe('workspace-resolution', () => {
             const dir = path.join(tempDir, 'my-workspace');
             fs.mkdirSync(dir, { recursive: true });
             const result = resolveWorkspaceDir(dir);
-            expect(result).to.equal(dir);
+            expect(result).toBe(dir);
         });
 
         it('should resolve a relative cliDir against cwd', () => {
             process.chdir(tempDir);
             fs.mkdirSync(path.join(tempDir, 'sub'), { recursive: true });
             const result = resolveWorkspaceDir('sub');
-            expect(result).to.equal(path.resolve(tempDir, 'sub'));
+            expect(result).toBe(path.resolve(tempDir, 'sub'));
         });
 
         it('should return cwd when no cliDir and not inside a known repo', () => {
             process.chdir(tempDir);
             const result = resolveWorkspaceDir();
-            expect(result).to.equal(tempDir);
+            expect(result).toBe(tempDir);
         });
 
         it('should return the parent of a known repo root when inside one', () => {
@@ -63,7 +63,7 @@ describe('workspace-resolution', () => {
             fs.mkdirSync(repoDir, { recursive: true });
             process.chdir(repoDir);
             const result = resolveWorkspaceDir();
-            expect(result).to.equal(tempDir);
+            expect(result).toBe(tempDir);
         });
 
         it('should walk up from a nested directory inside a known repo', () => {
@@ -72,7 +72,7 @@ describe('workspace-resolution', () => {
             fs.mkdirSync(nestedDir, { recursive: true });
             process.chdir(nestedDir);
             const result = resolveWorkspaceDir();
-            expect(result).to.equal(tempDir);
+            expect(result).toBe(tempDir);
         });
     });
 });
@@ -95,7 +95,7 @@ describe('repo-discovery', () => {
             fs.mkdirSync(path.join(tempDir, 'glsp-client'));
             fs.mkdirSync(path.join(tempDir, 'glsp-server-node'));
             const repos = discoverRepos(tempDir);
-            expect(repos).to.deep.equal(['glsp-server-node', 'glsp-client']);
+            expect(repos).toEqual(['glsp-server-node', 'glsp-client']);
         });
 
         it('should ignore non-GLSP directories', () => {
@@ -103,19 +103,19 @@ describe('repo-discovery', () => {
             fs.mkdirSync(path.join(tempDir, 'my-project'));
             fs.mkdirSync(path.join(tempDir, 'node_modules'));
             const repos = discoverRepos(tempDir);
-            expect(repos).to.deep.equal(['glsp-client']);
+            expect(repos).toEqual(['glsp-client']);
         });
 
         it('should ignore files matching GLSP repo names', () => {
             fs.mkdirSync(path.join(tempDir, 'glsp-client'));
             fs.writeFileSync(path.join(tempDir, 'glsp-server-node'), 'not a dir');
             const repos = discoverRepos(tempDir);
-            expect(repos).to.deep.equal(['glsp-client']);
+            expect(repos).toEqual(['glsp-client']);
         });
 
         it('should return empty array for nonexistent directory', () => {
             const repos = discoverRepos(path.join(tempDir, 'nonexistent'));
-            expect(repos).to.deep.equal([]);
+            expect(repos).toEqual([]);
         });
 
         it('should return repos sorted by GLSPRepo.choices order', () => {
@@ -123,13 +123,13 @@ describe('repo-discovery', () => {
             fs.mkdirSync(path.join(tempDir, 'glsp'));
             fs.mkdirSync(path.join(tempDir, 'glsp-client'));
             const repos = discoverRepos(tempDir);
-            expect(repos).to.deep.equal(['glsp', 'glsp-client', 'glsp-theia-integration']);
+            expect(repos).toEqual(['glsp', 'glsp-client', 'glsp-theia-integration']);
         });
 
         it('should return empty array when no GLSP repos exist', () => {
             fs.mkdirSync(path.join(tempDir, 'some-project'));
             const repos = discoverRepos(tempDir);
-            expect(repos).to.deep.equal([]);
+            expect(repos).toEqual([]);
         });
     });
 });
@@ -144,22 +144,22 @@ describe('repo-graph', () => {
             const glspIdx = order.indexOf('glsp');
             const clientIdx = order.indexOf('glsp-client');
             const serverNodeIdx = order.indexOf('glsp-server-node');
-            expect(glspIdx).to.be.lessThan(clientIdx);
-            expect(clientIdx).to.be.lessThan(serverNodeIdx);
+            expect(glspIdx).toBeLessThan(clientIdx);
+            expect(clientIdx).toBeLessThan(serverNodeIdx);
         });
 
         it('should include only requested repos', () => {
             const repos: GLSPRepo[] = ['glsp-client', 'glsp-server-node'];
             const order = getBuildOrder(repos);
-            expect(order).to.have.lengthOf(2);
-            expect(order).to.include('glsp-client');
-            expect(order).to.include('glsp-server-node');
+            expect(order).toHaveLength(2);
+            expect(order).toContain('glsp-client');
+            expect(order).toContain('glsp-server-node');
         });
 
         it('should handle independent repos', () => {
             const repos: GLSPRepo[] = ['glsp-playwright'];
             const order = getBuildOrder(repos);
-            expect(order).to.deep.equal(['glsp-playwright']);
+            expect(order).toEqual(['glsp-playwright']);
         });
 
         it('should place glsp-server before glsp-eclipse-integration', () => {
@@ -167,22 +167,22 @@ describe('repo-graph', () => {
             const order = getBuildOrder(repos);
             const serverIdx = order.indexOf('glsp-server');
             const eclipseIdx = order.indexOf('glsp-eclipse-integration');
-            expect(serverIdx).to.be.lessThan(eclipseIdx);
+            expect(serverIdx).toBeLessThan(eclipseIdx);
         });
     });
 
     describe('isLeafRepo', () => {
         it('should return true for repos that no other repo depends on', () => {
-            expect(isLeafRepo('glsp-theia-integration')).to.be.true;
-            expect(isLeafRepo('glsp-vscode-integration')).to.be.true;
-            expect(isLeafRepo('glsp-playwright')).to.be.true;
+            expect(isLeafRepo('glsp-theia-integration')).toBe(true);
+            expect(isLeafRepo('glsp-vscode-integration')).toBe(true);
+            expect(isLeafRepo('glsp-playwright')).toBe(true);
         });
 
         it('should return false for repos that are dependencies of other repos', () => {
-            expect(isLeafRepo('glsp')).to.be.false;
-            expect(isLeafRepo('glsp-client')).to.be.false;
-            expect(isLeafRepo('glsp-server-node')).to.be.false;
-            expect(isLeafRepo('glsp-server')).to.be.false;
+            expect(isLeafRepo('glsp')).toBe(false);
+            expect(isLeafRepo('glsp-client')).toBe(false);
+            expect(isLeafRepo('glsp-server-node')).toBe(false);
+            expect(isLeafRepo('glsp-server')).toBe(false);
         });
     });
 });
diff --git a/dev-packages/cli/src/commands/repo/fork.spec.ts b/dev-packages/cli/src/commands/repo/fork.spec.ts
index 7bc780b..6042403 100644
--- a/dev-packages/cli/src/commands/repo/fork.spec.ts
+++ b/dev-packages/cli/src/commands/repo/fork.spec.ts
@@ -26,33 +26,33 @@ import { configureForkRemote } from './fork';
 describe('fork-utils', () => {
     describe('getRemoteUrl', () => {
         it('should return SSH URL for ssh protocol', () => {
-            expect(getRemoteUrl('ssh', 'myuser', 'glsp-client')).to.equal('git@github.com:myuser/glsp-client.git');
+            expect(getRemoteUrl('ssh', 'myuser', 'glsp-client')).toBe('git@github.com:myuser/glsp-client.git');
         });
 
         it('should return HTTPS URL for https protocol', () => {
-            expect(getRemoteUrl('https', 'myuser', 'glsp-client')).to.equal('https://github.com/myuser/glsp-client.git');
+            expect(getRemoteUrl('https', 'myuser', 'glsp-client')).toBe('https://github.com/myuser/glsp-client.git');
         });
 
         it('should return HTTPS URL for gh protocol', () => {
-            expect(getRemoteUrl('gh', 'myuser', 'glsp-client')).to.equal('https://github.com/myuser/glsp-client.git');
+            expect(getRemoteUrl('gh', 'myuser', 'glsp-client')).toBe('https://github.com/myuser/glsp-client.git');
         });
     });
 
     describe('remoteMatchesOrg', () => {
         it('should match HTTPS URL', () => {
-            expect(remoteMatchesOrg('https://github.com/eclipse-glsp/glsp-client.git', 'eclipse-glsp', 'glsp-client')).to.be.true;
+            expect(remoteMatchesOrg('https://github.com/eclipse-glsp/glsp-client.git', 'eclipse-glsp', 'glsp-client')).toBe(true);
         });
 
         it('should match SSH URL', () => {
-            expect(remoteMatchesOrg('git@github.com:eclipse-glsp/glsp-client.git', 'eclipse-glsp', 'glsp-client')).to.be.true;
+            expect(remoteMatchesOrg('git@github.com:eclipse-glsp/glsp-client.git', 'eclipse-glsp', 'glsp-client')).toBe(true);
         });
 
         it('should not match different org', () => {
-            expect(remoteMatchesOrg('https://github.com/myuser/glsp-client.git', 'eclipse-glsp', 'glsp-client')).to.be.false;
+            expect(remoteMatchesOrg('https://github.com/myuser/glsp-client.git', 'eclipse-glsp', 'glsp-client')).toBe(false);
         });
 
         it('should not match different repo', () => {
-            expect(remoteMatchesOrg('https://github.com/eclipse-glsp/glsp-server-node.git', 'eclipse-glsp', 'glsp-client')).to.be.false;
+            expect(remoteMatchesOrg('https://github.com/eclipse-glsp/glsp-server-node.git', 'eclipse-glsp', 'glsp-client')).toBe(false);
         });
     });
 
@@ -65,14 +65,14 @@ describe('fork-utils', () => {
                 origin: 'git@github.com:myuser/glsp-client.git',
                 upstream: 'https://github.com/eclipse-glsp/glsp-client.git'
             };
-            expect(analyzeForkRemotes(remotes, forkUser, repo)).to.equal('already-configured');
+            expect(analyzeForkRemotes(remotes, forkUser, repo)).toBe('already-configured');
         });
 
         it('should return rename-origin when origin=eclipse-glsp and no upstream', () => {
             const remotes: RemoteInfo = {
                 origin: 'https://github.com/eclipse-glsp/glsp-client.git'
             };
-            expect(analyzeForkRemotes(remotes, forkUser, repo)).to.equal('rename-origin');
+            expect(analyzeForkRemotes(remotes, forkUser, repo)).toBe('rename-origin');
         });
 
         it('should return set-origin when origin=eclipse-glsp and upstream=eclipse-glsp', () => {
@@ -80,7 +80,7 @@ describe('fork-utils', () => {
                 origin: 'https://github.com/eclipse-glsp/glsp-client.git',
                 upstream: 'https://github.com/eclipse-glsp/glsp-client.git'
             };
-            expect(analyzeForkRemotes(remotes, forkUser, repo)).to.equal('set-origin');
+            expect(analyzeForkRemotes(remotes, forkUser, repo)).toBe('set-origin');
         });
 
         it('should return unexpected when origin=eclipse-glsp and upstream=something-else', () => {
@@ -88,33 +88,33 @@ describe('fork-utils', () => {
                 origin: 'https://github.com/eclipse-glsp/glsp-client.git',
                 upstream: 'https://github.com/other-org/glsp-client.git'
             };
-            expect(analyzeForkRemotes(remotes, forkUser, repo)).to.equal('unexpected');
+            expect(analyzeForkRemotes(remotes, forkUser, repo)).toBe('unexpected');
         });
 
         it('should return unexpected when origin is unknown org', () => {
             const remotes: RemoteInfo = {
                 origin: 'https://github.com/other-org/glsp-client.git'
             };
-            expect(analyzeForkRemotes(remotes, forkUser, repo)).to.equal('unexpected');
+            expect(analyzeForkRemotes(remotes, forkUser, repo)).toBe('unexpected');
         });
 
         it('should return unexpected when no remotes exist', () => {
             const remotes: RemoteInfo = {};
-            expect(analyzeForkRemotes(remotes, forkUser, repo)).to.equal('unexpected');
+            expect(analyzeForkRemotes(remotes, forkUser, repo)).toBe('unexpected');
         });
 
         it('should return unexpected when only upstream exists', () => {
             const remotes: RemoteInfo = {
                 upstream: 'https://github.com/eclipse-glsp/glsp-client.git'
             };
-            expect(analyzeForkRemotes(remotes, forkUser, repo)).to.equal('unexpected');
+            expect(analyzeForkRemotes(remotes, forkUser, repo)).toBe('unexpected');
         });
 
         it('should handle SSH URLs for eclipse-glsp origin', () => {
             const remotes: RemoteInfo = {
                 origin: 'git@github.com:eclipse-glsp/glsp-client.git'
             };
-            expect(analyzeForkRemotes(remotes, forkUser, repo)).to.equal('rename-origin');
+            expect(analyzeForkRemotes(remotes, forkUser, repo)).toBe('rename-origin');
         });
     });
 });
@@ -152,10 +152,10 @@ describe('fork-action', () => {
 
             expect(ensureForkStub).toHaveBeenCalledExactlyOnceWith('myuser', 'glsp-client');
             const calls = execStub.mock.calls.map(c => c[0] as string);
-            expect(calls).to.include('git remote rename origin upstream');
+            expect(calls).toContain('git remote rename origin upstream');
             const addOrigin = calls.find(c => c.includes('git remote add origin'));
-            expect(addOrigin).to.exist;
-            expect(addOrigin).to.contain('git@github.com:myuser/glsp-client.git');
+            expect(addOrigin).toBeDefined();
+            expect(addOrigin).toContain('git@github.com:myuser/glsp-client.git');
         });
 
         it('should set origin URL for set-origin flow', async () => {
@@ -170,8 +170,8 @@ describe('fork-action', () => {
             expect(ensureForkStub).toHaveBeenCalledExactlyOnceWith('myuser', 'glsp-client');
             const calls = execStub.mock.calls.map(c => c[0] as string);
             const setUrl = calls.find(c => c.includes('git remote set-url origin'));
-            expect(setUrl).to.exist;
-            expect(setUrl).to.contain('https://github.com/myuser/glsp-client.git');
+            expect(setUrl).toBeDefined();
+            expect(setUrl).toContain('https://github.com/myuser/glsp-client.git');
         });
 
         it('should skip when already configured', async () => {
@@ -204,7 +204,7 @@ describe('fork-action', () => {
             await configureForkRemote('glsp-client', repoDir, 'myuser', 'ssh');
 
             const addOriginCall = execStub.mock.calls.find(c => (c[0] as string).includes('git remote add origin'));
-            expect(addOriginCall![0]).to.contain('git@github.com:myuser/glsp-client.git');
+            expect(addOriginCall![0]).toContain('git@github.com:myuser/glsp-client.git');
         });
 
         it('should use https URL when protocol is https', async () => {
@@ -214,7 +214,7 @@ describe('fork-action', () => {
             await configureForkRemote('glsp-client', repoDir, 'myuser', 'https');
 
             const addOriginCall = execStub.mock.calls.find(c => (c[0] as string).includes('git remote add origin'));
-            expect(addOriginCall![0]).to.contain('https://github.com/myuser/glsp-client.git');
+            expect(addOriginCall![0]).toContain('https://github.com/myuser/glsp-client.git');
         });
 
         it('should pass correct cwd for git commands', async () => {
@@ -224,7 +224,7 @@ describe('fork-action', () => {
             await configureForkRemote('glsp-server-node', repoDir, 'myuser', 'ssh');
 
             for (const call of execStub.mock.calls) {
-                expect(call[1]).to.have.property('cwd', repoDir);
+                expect(call[1]).toHaveProperty('cwd', repoDir);
             }
         });
 
diff --git a/dev-packages/cli/src/commands/repo/link.spec.ts b/dev-packages/cli/src/commands/repo/link.spec.ts
index a588b2f..7106e80 100644
--- a/dev-packages/cli/src/commands/repo/link.spec.ts
+++ b/dev-packages/cli/src/commands/repo/link.spec.ts
@@ -115,17 +115,17 @@ describe('link-action', () => {
     describe('filterLinkableRepos', () => {
         it('should keep linkable npm repos', () => {
             const result = filterLinkableRepos(['glsp-client', 'glsp-server-node', 'glsp-theia-integration'] as GLSPRepo[]);
-            expect(result).to.deep.equal(['glsp-client', 'glsp-server-node', 'glsp-theia-integration']);
+            expect(result).toEqual(['glsp-client', 'glsp-server-node', 'glsp-theia-integration']);
         });
 
         it('should keep glsp-eclipse-integration', () => {
             const result = filterLinkableRepos(['glsp-client', 'glsp-eclipse-integration'] as GLSPRepo[]);
-            expect(result).to.deep.equal(['glsp-client', 'glsp-eclipse-integration']);
+            expect(result).toEqual(['glsp-client', 'glsp-eclipse-integration']);
         });
 
         it('should exclude non-linkable repos', () => {
             const result = filterLinkableRepos(['glsp-client', 'glsp-server', 'glsp-playwright'] as GLSPRepo[]);
-            expect(result).to.deep.equal(['glsp-client']);
+            expect(result).toEqual(['glsp-client']);
         });
     });
 
@@ -143,8 +143,8 @@ describe('link-action', () => {
                 return [];
             });
             const result = getGLSPWorkspacePackages(repoDir);
-            expect(result).to.have.length(2);
-            expect(result.map(p => p.name)).to.deep.equal(['@eclipse-glsp/client', '@eclipse-glsp/protocol']);
+            expect(result).toHaveLength(2);
+            expect(result.map(p => p.name)).toEqual(['@eclipse-glsp/client', '@eclipse-glsp/protocol']);
         });
     });
 
@@ -160,7 +160,7 @@ describe('link-action', () => {
                 }
                 return [];
             });
-            expect(collectProvidedPackages(repoDir)).to.deep.equal({
+            expect(collectProvidedPackages(repoDir)).toEqual({
                 '@eclipse-glsp/client': path.join(repoDir, 'packages/client'),
                 '@eclipse-glsp/protocol': path.join(repoDir, 'packages/protocol')
             });
@@ -172,7 +172,7 @@ describe('link-action', () => {
             createNodeModules('glsp-client', 'sprotty');
             const clientDir = path.join(tempDir, 'glsp-client');
             const dir = resolveSingletonDir([clientDir], 'sprotty');
-            expect(dir).to.equal(fs.realpathSync(path.join(clientDir, 'node_modules', 'sprotty')));
+            expect(dir).toBe(fs.realpathSync(path.join(clientDir, 'node_modules', 'sprotty')));
         });
 
         it('should walk up to the package root when the entry has a nested manifest', () => {
@@ -186,13 +186,13 @@ describe('link-action', () => {
             fs.writeFileSync(path.join(invDir, 'lib', 'cjs', 'package.json'), JSON.stringify({ type: 'commonjs' }));
             fs.writeFileSync(path.join(invDir, 'lib', 'cjs', 'index.js'), 'module.exports = {};');
 
-            expect(resolveSingletonDir([clientDir], 'inversify')).to.equal(fs.realpathSync(invDir));
+            expect(resolveSingletonDir([clientDir], 'inversify')).toBe(fs.realpathSync(invDir));
         });
 
         it('should return undefined when the dependency is not resolvable from any dir', () => {
             createRepoDirs('glsp-client');
             fs.writeFileSync(path.join(tempDir, 'glsp-client', 'package.json'), JSON.stringify({ name: 'glsp-client' }));
-            expect(resolveSingletonDir([path.join(tempDir, 'glsp-client')], 'sprotty')).to.be.undefined;
+            expect(resolveSingletonDir([path.join(tempDir, 'glsp-client')], 'sprotty')).toBeUndefined();
         });
     });
 
@@ -202,10 +202,10 @@ describe('link-action', () => {
             createNodeModules('glsp-client', 'sprotty', 'inversify');
             const clientDir = path.join(tempDir, 'glsp-client');
             const links = collectSingletonLinks(clientDir);
-            expect(links.sprotty).to.equal(fs.realpathSync(path.join(clientDir, 'node_modules', 'sprotty')));
-            expect(links.inversify).to.equal(fs.realpathSync(path.join(clientDir, 'node_modules', 'inversify')));
+            expect(links.sprotty).toBe(fs.realpathSync(path.join(clientDir, 'node_modules', 'sprotty')));
+            expect(links.inversify).toBe(fs.realpathSync(path.join(clientDir, 'node_modules', 'inversify')));
             // unresolvable singletons (sprotty-protocol, etc.) are simply skipped
-            expect(links['sprotty-protocol']).to.be.undefined;
+            expect(links['sprotty-protocol']).toBeUndefined();
         });
     });
 
@@ -217,8 +217,8 @@ describe('link-action', () => {
             applyLinkOverrides(repoDir, { '@eclipse-glsp/protocol': path.join(tempDir, 'glsp-client/packages/protocol') });
 
             const workspace = readWorkspaceYaml('glsp-server-node');
-            expect(workspace.packages).to.deep.equal(['packages/*']);
-            expect(workspace.overrides).to.deep.equal({
+            expect(workspace.packages).toEqual(['packages/*']);
+            expect(workspace.overrides).toEqual({
                 foo: '1.0.0',
                 '@eclipse-glsp/protocol': 'link:../glsp-client/packages/protocol'
             });
@@ -228,14 +228,14 @@ describe('link-action', () => {
             createRepoDirs('glsp-server-node');
             const repoDir = path.join(tempDir, 'glsp-server-node');
             applyLinkOverrides(repoDir, { sprotty: path.join(tempDir, 'glsp-client/node_modules/sprotty') });
-            expect(readWorkspaceYaml('glsp-server-node').overrides).to.deep.equal({ sprotty: 'link:../glsp-client/node_modules/sprotty' });
+            expect(readWorkspaceYaml('glsp-server-node').overrides).toEqual({ sprotty: 'link:../glsp-client/node_modules/sprotty' });
         });
 
         it('should be a no-op for empty links', () => {
             createRepoDirs('glsp-server-node');
             const repoDir = path.join(tempDir, 'glsp-server-node');
             applyLinkOverrides(repoDir, {});
-            expect(fs.existsSync(path.join(repoDir, 'pnpm-workspace.yaml'))).to.be.false;
+            expect(fs.existsSync(path.join(repoDir, 'pnpm-workspace.yaml'))).toBe(false);
         });
     });
 
@@ -252,10 +252,10 @@ describe('link-action', () => {
                 }
             });
             const removed = removeLinkOverrides(path.join(tempDir, 'glsp-server-node'));
-            expect(removed).to.be.true;
+            expect(removed).toBe(true);
             const workspace = readWorkspaceYaml('glsp-server-node');
-            expect(workspace.packages).to.deep.equal(['packages/*']);
-            expect(workspace.overrides).to.deep.equal({ 'some-dep': '1.2.3' });
+            expect(workspace.packages).toEqual(['packages/*']);
+            expect(workspace.overrides).toEqual({ 'some-dep': '1.2.3' });
         });
 
         it('should drop the overrides key when it becomes empty', () => {
@@ -265,20 +265,20 @@ describe('link-action', () => {
                 overrides: { '@eclipse-glsp/protocol': 'link:../glsp-client/packages/protocol' }
             });
             removeLinkOverrides(path.join(tempDir, 'glsp-server-node'));
-            expect(readWorkspaceYaml('glsp-server-node')).to.not.have.property('overrides');
+            expect(readWorkspaceYaml('glsp-server-node')).not.toHaveProperty('overrides');
         });
 
         it('should not touch non-link overrides for the same package', () => {
             createRepoDirs('glsp-server-node');
             writeWorkspaceYaml('glsp-server-node', { overrides: { sprotty: '1.4.0' } });
             const removed = removeLinkOverrides(path.join(tempDir, 'glsp-server-node'));
-            expect(removed).to.be.false;
-            expect(readWorkspaceYaml('glsp-server-node').overrides).to.deep.equal({ sprotty: '1.4.0' });
+            expect(removed).toBe(false);
+            expect(readWorkspaceYaml('glsp-server-node').overrides).toEqual({ sprotty: '1.4.0' });
         });
 
         it('should return false when no workspace file exists', () => {
             createRepoDirs('glsp-server-node');
-            expect(removeLinkOverrides(path.join(tempDir, 'glsp-server-node'))).to.be.false;
+            expect(removeLinkOverrides(path.join(tempDir, 'glsp-server-node'))).toBe(false);
         });
     });
 
@@ -291,21 +291,21 @@ describe('link-action', () => {
             await runLink(['glsp-client', 'glsp-server-node'] as GLSPRepo[], makeOptions());
 
             // glsp-client is the source of truth and gets no overrides.
-            expect(readWorkspaceYaml('glsp-client')).to.not.have.property('overrides');
+            expect(readWorkspaceYaml('glsp-client')).not.toHaveProperty('overrides');
 
             // glsp-server-node consumes glsp-client's packages and the shared singletons.
             const serverOverrides = readWorkspaceYaml('glsp-server-node').overrides ?? {};
-            expect(serverOverrides['@eclipse-glsp/client']).to.equal('link:../glsp-client/packages/client');
-            expect(serverOverrides['@eclipse-glsp/protocol']).to.equal('link:../glsp-client/packages/protocol');
+            expect(serverOverrides['@eclipse-glsp/client']).toBe('link:../glsp-client/packages/client');
+            expect(serverOverrides['@eclipse-glsp/protocol']).toBe('link:../glsp-client/packages/protocol');
             for (const dep of SINGLETON_DEPS) {
-                expect(serverOverrides[dep]).to.equal(`link:../glsp-client/node_modules/${dep}`);
+                expect(serverOverrides[dep]).toBe(`link:../glsp-client/node_modules/${dep}`);
             }
 
             // Each repo is installed (to apply the overrides) and then built, in build order:
             // install client, build client, install server-node, build server-node.
-            expect(execAsyncStub.mock.calls.length).to.equal(4);
+            expect(execAsyncStub.mock.calls.length).toBe(4);
             const calls = execAsyncStub.mock.calls.map(c => [c[0], c[1].cwd] as const);
-            expect(calls).to.deep.equal([
+            expect(calls).toEqual([
                 ['pnpm install --no-frozen-lockfile', path.join(tempDir, 'glsp-client')],
                 ['pnpm run --if-present build', path.join(tempDir, 'glsp-client')],
                 ['pnpm install --no-frozen-lockfile', path.join(tempDir, 'glsp-server-node')],
@@ -321,8 +321,8 @@ describe('link-action', () => {
             await runLink(['glsp-client', 'glsp-server-node'] as GLSPRepo[], makeOptions({ build: false }));
 
             // Only the override-applying install runs per repo; no build.
-            expect(execAsyncStub.mock.calls.length).to.equal(2);
-            expect(execAsyncStub.mock.calls.every(c => c[0] === 'pnpm install --no-frozen-lockfile')).to.be.true;
+            expect(execAsyncStub.mock.calls.length).toBe(2);
+            expect(execAsyncStub.mock.calls.every(c => c[0] === 'pnpm install --no-frozen-lockfile')).toBe(true);
         });
 
         it('should link into the client/ subdir for glsp-eclipse-integration', async () => {
@@ -336,20 +336,20 @@ describe('link-action', () => {
             await runLink(['glsp-client', 'glsp-eclipse-integration'] as GLSPRepo[], makeOptions({ build: false }));
 
             // Overrides go into client/pnpm-workspace.yaml, not the repo root.
-            expect(fs.existsSync(path.join(tempDir, 'glsp-eclipse-integration', 'pnpm-workspace.yaml'))).to.be.false;
+            expect(fs.existsSync(path.join(tempDir, 'glsp-eclipse-integration', 'pnpm-workspace.yaml'))).toBe(false);
             const overrides = (YAML.parse(fs.readFileSync(path.join(clientDir, 'pnpm-workspace.yaml'), 'utf8')).overrides ?? {}) as Record<
                 string,
                 string
             >;
             // Relative link paths gain an extra ../ because the workspace is one level deeper than the repo root.
-            expect(overrides['@eclipse-glsp/client']).to.equal('link:../../glsp-client/packages/client');
+            expect(overrides['@eclipse-glsp/client']).toBe('link:../../glsp-client/packages/client');
             for (const dep of SINGLETON_DEPS) {
-                expect(overrides[dep]).to.equal(`link:../../glsp-client/node_modules/${dep}`);
+                expect(overrides[dep]).toBe(`link:../../glsp-client/node_modules/${dep}`);
             }
 
             // The install runs in the client/ workspace, not the repo root.
             const eclipseInstall = execAsyncStub.mock.calls.find(c => c[1].cwd === clientDir);
-            expect(eclipseInstall, 'install should run in client/').to.not.be.undefined;
+            expect(eclipseInstall, 'install should run in client/').toBeDefined();
         });
 
         it('should stop on first failure when failFast is true', async () => {
@@ -360,9 +360,9 @@ describe('link-action', () => {
                 await runLink(['glsp-client', 'glsp-server-node'] as GLSPRepo[], makeOptions({ failFast: true }));
                 expect.fail('should have thrown');
             } catch (error) {
-                expect((error as Error).message).to.contain('failed to link');
+                expect((error as Error).message).toContain('failed to link');
             }
-            expect(execAsyncStub.mock.calls.length).to.equal(1);
+            expect(execAsyncStub.mock.calls.length).toBe(1);
         });
 
         it('should skip non-linkable repos', async () => {
@@ -384,11 +384,11 @@ describe('link-action', () => {
 
             await runUnlink(['glsp-client', 'glsp-server-node'] as GLSPRepo[], makeOptions());
 
-            expect(readWorkspaceYaml('glsp-server-node')).to.not.have.property('overrides');
+            expect(readWorkspaceYaml('glsp-server-node')).not.toHaveProperty('overrides');
             // Only glsp-server-node had overrides, so only it is reinstalled.
-            expect(execAsyncStub.mock.calls.length).to.equal(1);
-            expect(execAsyncStub.mock.calls[0][0]).to.equal('pnpm install --no-frozen-lockfile');
-            expect(execAsyncStub.mock.calls[0][1].cwd).to.equal(path.join(tempDir, 'glsp-server-node'));
+            expect(execAsyncStub.mock.calls.length).toBe(1);
+            expect(execAsyncStub.mock.calls[0][0]).toBe('pnpm install --no-frozen-lockfile');
+            expect(execAsyncStub.mock.calls[0][1].cwd).toBe(path.join(tempDir, 'glsp-server-node'));
         });
 
         it('should stop on first failure when failFast is true', async () => {
@@ -401,7 +401,7 @@ describe('link-action', () => {
                 await runUnlink(['glsp-client', 'glsp-server-node'] as GLSPRepo[], makeOptions({ failFast: true }));
                 expect.fail('should have thrown');
             } catch (error) {
-                expect((error as Error).message).to.contain('failed to unlink');
+                expect((error as Error).message).toContain('failed to unlink');
             }
         });
     });
diff --git a/dev-packages/cli/src/commands/repo/repo.spec.ts b/dev-packages/cli/src/commands/repo/repo.spec.ts
index 0f39620..79367a4 100644
--- a/dev-packages/cli/src/commands/repo/repo.spec.ts
+++ b/dev-packages/cli/src/commands/repo/repo.spec.ts
@@ -61,7 +61,7 @@ describe('repo --dir propagation', () => {
         parent.addCommand(createLeaf(captured));
 
         await parent.parseAsync(['node', 'test', '-d', '/test/path', 'leaf'], { from: 'node' });
-        expect(captured.dir).to.equal('/test/path');
+        expect(captured.dir).toBe('/test/path');
     });
 
     it('should not override subcommand --dir when explicitly set', async () => {
@@ -70,7 +70,7 @@ describe('repo --dir propagation', () => {
         parent.addCommand(createLeaf(captured));
 
         await parent.parseAsync(['node', 'test', '-d', '/parent', 'leaf', '-d', '/child'], { from: 'node' });
-        expect(captured.dir).to.equal('/child');
+        expect(captured.dir).toBe('/child');
     });
 
     it('should propagate --dir through middle layer to leaf', async () => {
@@ -81,7 +81,7 @@ describe('repo --dir propagation', () => {
         parent.addCommand(middle);
 
         await parent.parseAsync(['node', 'test', '-d', '/deep/path', 'middle', 'leaf'], { from: 'node' });
-        expect(captured.dir).to.equal('/deep/path');
+        expect(captured.dir).toBe('/deep/path');
     });
 
     it('should not propagate when parent --dir is not set', async () => {
@@ -90,7 +90,7 @@ describe('repo --dir propagation', () => {
         parent.addCommand(createLeaf(captured));
 
         await parent.parseAsync(['node', 'test', 'leaf'], { from: 'node' });
-        expect(captured.dir).to.be.undefined;
+        expect(captured.dir).toBeUndefined();
     });
 
     it('should allow leaf --dir to override through middle layer', async () => {
@@ -101,6 +101,6 @@ describe('repo --dir propagation', () => {
         parent.addCommand(middle);
 
         await parent.parseAsync(['node', 'test', '-d', '/parent', 'middle', 'leaf', '-d', '/leaf'], { from: 'node' });
-        expect(captured.dir).to.equal('/leaf');
+        expect(captured.dir).toBe('/leaf');
     });
 });
diff --git a/dev-packages/cli/src/commands/repo/run.spec.ts b/dev-packages/cli/src/commands/repo/run.spec.ts
index c0de57e..f31d773 100644
--- a/dev-packages/cli/src/commands/repo/run.spec.ts
+++ b/dev-packages/cli/src/commands/repo/run.spec.ts
@@ -21,29 +21,29 @@ describe('run-command', () => {
     describe('createScopedRunCommand', () => {
         it('should create a command named "run"', () => {
             const cmd = createScopedRunCommand('glsp-client');
-            expect(cmd.name()).to.equal('run');
+            expect(cmd.name()).toBe('run');
         });
 
         it('should include the repo name in the description', () => {
             const cmd = createScopedRunCommand('glsp-server-node');
-            expect(cmd.description()).to.contain('glsp-server-node');
+            expect(cmd.description()).toContain('glsp-server-node');
         });
 
         it('should require a script argument', () => {
             const cmd = createScopedRunCommand('glsp-client');
             const scriptArg = cmd.registeredArguments.find(a => a.name() === 'script');
-            expect(scriptArg).to.not.be.undefined;
-            expect(scriptArg!.required).to.be.true;
+            expect(scriptArg).toBeDefined();
+            expect(scriptArg!.required).toBe(true);
         });
 
         it('should allow unknown options for passthrough', () => {
             const cmd = createScopedRunCommand('glsp-client');
-            expect((cmd as any)._allowUnknownOption).to.be.true;
+            expect((cmd as any)._allowUnknownOption).toBe(true);
         });
 
         it('should allow excess arguments for passthrough', () => {
             const cmd = createScopedRunCommand('glsp-client');
-            expect((cmd as any)._allowExcessArguments).to.be.true;
+            expect((cmd as any)._allowExcessArguments).toBe(true);
         });
     });
 });
diff --git a/dev-packages/cli/src/commands/repo/server-node.spec.ts b/dev-packages/cli/src/commands/repo/server-node.spec.ts
index fb3db82..9f6eb4e 100644
--- a/dev-packages/cli/src/commands/repo/server-node.spec.ts
+++ b/dev-packages/cli/src/commands/repo/server-node.spec.ts
@@ -42,27 +42,27 @@ describe('server-node', () => {
         it('should return absolute path when browser bundle exists', () => {
             createBundle(BROWSER_BUNDLE_PATH);
             const result = resolveBundlePath(tempDir, BROWSER_BUNDLE_PATH, 'Browser bundle');
-            expect(result).to.equal(path.resolve(tempDir, BROWSER_BUNDLE_PATH));
+            expect(result).toBe(path.resolve(tempDir, BROWSER_BUNDLE_PATH));
         });
 
         it('should return absolute path when node bundle exists', () => {
             createBundle(NODE_BUNDLE_PATH);
             const result = resolveBundlePath(tempDir, NODE_BUNDLE_PATH, 'Node server bundle');
-            expect(result).to.equal(path.resolve(tempDir, NODE_BUNDLE_PATH));
+            expect(result).toBe(path.resolve(tempDir, NODE_BUNDLE_PATH));
         });
 
         it('should throw when bundle does not exist', () => {
-            expect(() => resolveBundlePath(tempDir, BROWSER_BUNDLE_PATH, 'Browser bundle')).to.throw(/Browser bundle not found/);
+            expect(() => resolveBundlePath(tempDir, BROWSER_BUNDLE_PATH, 'Browser bundle')).toThrow(/Browser bundle not found/);
         });
 
         it('should include the expected path in the error message', () => {
-            expect(() => resolveBundlePath(tempDir, NODE_BUNDLE_PATH, 'Node server bundle')).to.throw(
+            expect(() => resolveBundlePath(tempDir, NODE_BUNDLE_PATH, 'Node server bundle')).toThrow(
                 new RegExp(NODE_BUNDLE_PATH.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'))
             );
         });
 
         it('should include build hint in the error message', () => {
-            expect(() => resolveBundlePath(tempDir, BROWSER_BUNDLE_PATH, 'Browser bundle')).to.throw(/glsp repo server-node build/);
+            expect(() => resolveBundlePath(tempDir, BROWSER_BUNDLE_PATH, 'Browser bundle')).toThrow(/glsp repo server-node build/);
         });
     });
 });
diff --git a/dev-packages/cli/src/commands/repo/start.spec.ts b/dev-packages/cli/src/commands/repo/start.spec.ts
index a3c3a1b..89928b0 100644
--- a/dev-packages/cli/src/commands/repo/start.spec.ts
+++ b/dev-packages/cli/src/commands/repo/start.spec.ts
@@ -61,7 +61,7 @@ describe('start-action', () => {
             const targetDir = createTargetDir();
             createJar(targetDir, 'org.eclipse.glsp.example.workflow-2.0.0-glsp.jar');
             const result = discoverJar(tempDir);
-            expect(result).to.contain('org.eclipse.glsp.example.workflow-2.0.0-glsp.jar');
+            expect(result).toContain('org.eclipse.glsp.example.workflow-2.0.0-glsp.jar');
         });
 
         it('should pick the newest JAR by mtime when multiple exist', () => {
@@ -69,38 +69,38 @@ describe('start-action', () => {
             createJar(targetDir, 'old-glsp.jar', 1000000);
             createJar(targetDir, 'new-glsp.jar', 2000000);
             const result = discoverJar(tempDir);
-            expect(result).to.contain('new-glsp.jar');
+            expect(result).toContain('new-glsp.jar');
         });
 
         it('should throw when no JAR is found', () => {
             createTargetDir();
-            expect(() => discoverJar(tempDir)).to.throw(/No \*-glsp\.jar found/);
+            expect(() => discoverJar(tempDir)).toThrow(/No \*-glsp\.jar found/);
         });
 
         it('should throw with helpful message when target directory does not exist', () => {
-            expect(() => discoverJar(tempDir)).to.throw(/glsp repo server build/);
+            expect(() => discoverJar(tempDir)).toThrow(/glsp repo server build/);
         });
     });
 
     describe('resolveCommand', () => {
         it('should resolve to a pnpm -C command', () => {
             const result = resolveCommand('start:websocket', tempDir, false);
-            expect(result).to.equal(`pnpm -C ${tempDir} start:websocket`);
+            expect(result).toBe(`pnpm -C ${tempDir} start:websocket`);
         });
 
         it('should return undefined on dry-run', () => {
             const result = resolveCommand('start:websocket', tempDir, true);
-            expect(result).to.be.undefined;
+            expect(result).toBeUndefined();
         });
 
         it('should handle scripts with arguments', () => {
             const result = resolveCommand('start:websocket --port 8081', tempDir, false);
-            expect(result).to.equal(`pnpm -C ${tempDir} start:websocket --port 8081`);
+            expect(result).toBe(`pnpm -C ${tempDir} start:websocket --port 8081`);
         });
 
         it('should work even when the repo is not cloned yet', () => {
             const result = resolveCommand('start:websocket', '/not/cloned/repo', false);
-            expect(result).to.equal('pnpm -C /not/cloned/repo start:websocket');
+            expect(result).toBe('pnpm -C /not/cloned/repo start:websocket');
         });
     });
 
@@ -114,11 +114,11 @@ describe('start-action', () => {
 
         for (const { name, cmd } of commands) {
             it(`${name} should allow unknown options`, () => {
-                expect((cmd as any)._allowUnknownOption).to.be.true;
+                expect((cmd as any)._allowUnknownOption).toBe(true);
             });
 
             it(`${name} should allow excess arguments`, () => {
-                expect((cmd as any)._allowExcessArguments).to.be.true;
+                expect((cmd as any)._allowExcessArguments).toBe(true);
             });
         }
     });
diff --git a/dev-packages/cli/src/commands/repo/switch.spec.ts b/dev-packages/cli/src/commands/repo/switch.spec.ts
index 08b83b5..f693414 100644
--- a/dev-packages/cli/src/commands/repo/switch.spec.ts
+++ b/dev-packages/cli/src/commands/repo/switch.spec.ts
@@ -56,25 +56,25 @@ describe('switch-action', () => {
     describe('validateReposExist', () => {
         it('should pass when all repos exist', () => {
             createRepoDirs('glsp-client', 'glsp-server-node');
-            expect(() => validateReposExist(['glsp-client', 'glsp-server-node'], tempDir)).to.not.throw();
+            expect(() => validateReposExist(['glsp-client', 'glsp-server-node'], tempDir)).not.toThrow();
         });
 
         it('should throw listing missing repos', () => {
             createRepoDirs('glsp-client');
-            expect(() => validateReposExist(['glsp-client', 'glsp-server-node'], tempDir)).to.throw(/not cloned.*glsp-server-node/);
+            expect(() => validateReposExist(['glsp-client', 'glsp-server-node'], tempDir)).toThrow(/not cloned.*glsp-server-node/);
         });
     });
 
     describe('validateReposClean', () => {
         it('should pass when all repos are clean', () => {
             createRepoDirs('glsp-client');
-            expect(() => validateReposClean(['glsp-client'], tempDir)).to.not.throw();
+            expect(() => validateReposClean(['glsp-client'], tempDir)).not.toThrow();
         });
 
         it('should throw listing dirty repos', () => {
             createRepoDirs('glsp-client');
             vi.mocked(gitUtil.hasChanges).mockReturnValue(true);
-            expect(() => validateReposClean(['glsp-client'], tempDir)).to.throw(/uncommitted changes.*glsp-client/);
+            expect(() => validateReposClean(['glsp-client'], tempDir)).toThrow(/uncommitted changes.*glsp-client/);
         });
     });
 
@@ -84,15 +84,15 @@ describe('switch-action', () => {
             switchSingleRepo('glsp-client', makeOptions({ branch: 'release/2.0' }));
             expect(execStub).toHaveBeenCalledOnce();
             const cmd = execStub.mock.calls[0][0] as string;
-            expect(cmd).to.contain('git checkout');
-            expect(cmd).to.contain('release/2.0');
+            expect(cmd).toContain('git checkout');
+            expect(cmd).toContain('release/2.0');
         });
 
         it('should add --force when force is true', () => {
             createRepoDirs('glsp-client');
             switchSingleRepo('glsp-client', makeOptions({ branch: 'main', force: true }));
             const cmd = execStub.mock.calls[0][0] as string;
-            expect(cmd).to.contain('--force');
+            expect(cmd).toContain('--force');
         });
 
         it('should warn and return when branch does not exist', () => {
@@ -100,7 +100,7 @@ describe('switch-action', () => {
             execStub.mockImplementation(() => {
                 throw new Error("error: pathspec 'nonexistent' did not match any");
             });
-            expect(() => switchSingleRepo('glsp-client', makeOptions({ branch: 'nonexistent' }))).to.not.throw();
+            expect(() => switchSingleRepo('glsp-client', makeOptions({ branch: 'nonexistent' }))).not.toThrow();
         });
 
         it('should rethrow on other git errors', () => {
@@ -108,15 +108,15 @@ describe('switch-action', () => {
             execStub.mockImplementation(() => {
                 throw new Error('fatal: some other error');
             });
-            expect(() => switchSingleRepo('glsp-client', makeOptions())).to.throw('fatal: some other error');
+            expect(() => switchSingleRepo('glsp-client', makeOptions())).toThrow('fatal: some other error');
         });
 
         it('should use gh pr checkout for --pr', () => {
             createRepoDirs('glsp-client');
             switchSingleRepo('glsp-client', makeOptions({ branch: undefined, pr: '42' }));
             const cmd = execStub.mock.calls[0][0] as string;
-            expect(cmd).to.contain('gh pr checkout 42');
-            expect(cmd).to.contain('-R eclipse-glsp/glsp-client');
+            expect(cmd).toContain('gh pr checkout 42');
+            expect(cmd).toContain('-R eclipse-glsp/glsp-client');
         });
     });
 });
diff --git a/dev-packages/cli/src/commands/repo/workspace.spec.ts b/dev-packages/cli/src/commands/repo/workspace.spec.ts
index baee3ee..52d68bd 100644
--- a/dev-packages/cli/src/commands/repo/workspace.spec.ts
+++ b/dev-packages/cli/src/commands/repo/workspace.spec.ts
@@ -48,9 +48,9 @@ describe('workspace-action', () => {
             const repos: GLSPRepo[] = ['glsp-client', 'glsp-server-node'];
             const result = generateWorkspaceContent(repos, tempDir, makeOptions());
 
-            expect(result.folders).to.have.length(2);
-            expect(result.folders[0]).to.deep.equal({ name: 'glsp-client', path: 'glsp-client' });
-            expect(result.folders[1]).to.deep.equal({ name: 'glsp-server-node', path: 'glsp-server-node' });
+            expect(result.folders).toHaveLength(2);
+            expect(result.folders[0]).toEqual({ name: 'glsp-client', path: 'glsp-client' });
+            expect(result.folders[1]).toEqual({ name: 'glsp-server-node', path: 'glsp-server-node' });
         });
 
         it('should compute paths relative to custom output location', () => {
@@ -59,23 +59,23 @@ describe('workspace-action', () => {
 
             const result = generateWorkspaceContent(repos, tempDir, makeOptions({ outputPath }));
 
-            expect(result.folders[0].path).to.equal(path.join('..', '..', 'glsp-client'));
+            expect(result.folders[0].path).toBe(path.join('..', '..', 'glsp-client'));
         });
 
         it('should include build, link, and unlink tasks', () => {
             const repos: GLSPRepo[] = ['glsp-client'];
             const result = generateWorkspaceContent(repos, tempDir, makeOptions());
 
-            expect(result.tasks.version).to.equal('2.0.0');
+            expect(result.tasks.version).toBe('2.0.0');
             const labels = result.tasks.tasks.map(t => t.label);
-            expect(labels).to.include('GLSP: Build all');
-            expect(labels).to.include('GLSP: Link');
-            expect(labels).to.include('GLSP: Unlink');
+            expect(labels).toContain('GLSP: Build all');
+            expect(labels).toContain('GLSP: Link');
+            expect(labels).toContain('GLSP: Unlink');
 
             const buildAll = result.tasks.tasks.find(t => t.label === 'GLSP: Build all')!;
-            expect(buildAll.type).to.equal('shell');
-            expect(buildAll.command).to.equal('npx @eclipse-glsp/cli repo build --no-java');
-            expect(buildAll.group).to.deep.equal({ kind: 'build', isDefault: true });
+            expect(buildAll.type).toBe('shell');
+            expect(buildAll.command).toBe('npx @eclipse-glsp/cli repo build --no-java');
+            expect(buildAll.group).toEqual({ kind: 'build', isDefault: true });
         });
 
         it('should include Java build task when Java repos are present', () => {
@@ -83,7 +83,7 @@ describe('workspace-action', () => {
             const result = generateWorkspaceContent(repos, tempDir, makeOptions());
 
             const labels = result.tasks.tasks.map(t => t.label);
-            expect(labels).to.include('GLSP: Build all (incl. Java)');
+            expect(labels).toContain('GLSP: Build all (incl. Java)');
         });
 
         it('should not include Java build task when no Java repos are present', () => {
@@ -91,7 +91,7 @@ describe('workspace-action', () => {
             const result = generateWorkspaceContent(repos, tempDir, makeOptions());
 
             const labels = result.tasks.tasks.map(t => t.label);
-            expect(labels).to.not.include('GLSP: Build all (incl. Java)');
+            expect(labels).not.toContain('GLSP: Build all (incl. Java)');
         });
 
         it('should include preset build tasks for matching strict subsets', () => {
@@ -99,14 +99,14 @@ describe('workspace-action', () => {
             const result = generateWorkspaceContent(repos, tempDir, makeOptions());
 
             const labels = result.tasks.tasks.map(t => t.label);
-            expect(labels).to.include('GLSP: Build core');
+            expect(labels).toContain('GLSP: Build core');
         });
 
         it('should include extension recommendations', () => {
             const repos: GLSPRepo[] = ['glsp-client'];
             const result = generateWorkspaceContent(repos, tempDir, makeOptions());
 
-            expect(result.extensions.recommendations).to.deep.equal([
+            expect(result.extensions.recommendations).toEqual([
                 'dbaeumer.vscode-eslint',
                 'esbenp.prettier-vscode',
                 'DavidAnson.vscode-markdownlint'
@@ -117,7 +117,7 @@ describe('workspace-action', () => {
             const repos: GLSPRepo[] = ['glsp-client'];
             const result = generateWorkspaceContent(repos, tempDir, makeOptions());
 
-            expect(result.settings).to.deep.equal({});
+            expect(result.settings).toEqual({});
         });
     });
 
@@ -126,11 +126,11 @@ describe('workspace-action', () => {
             const repos: GLSPRepo[] = ['glsp-client'];
             const outputFile = generateWorkspaceFile(repos, tempDir, makeOptions());
 
-            expect(outputFile).to.equal(path.join(tempDir, WORKSPACE_FILE_NAME));
-            expect(fs.existsSync(outputFile)).to.be.true;
+            expect(outputFile).toBe(path.join(tempDir, WORKSPACE_FILE_NAME));
+            expect(fs.existsSync(outputFile)).toBe(true);
 
             const content: VSCodeWorkspace = JSON.parse(fs.readFileSync(outputFile, 'utf-8'));
-            expect(content.folders).to.have.length(1);
+            expect(content.folders).toHaveLength(1);
         });
 
         it('should write to a custom output path', () => {
@@ -139,8 +139,8 @@ describe('workspace-action', () => {
 
             const outputFile = generateWorkspaceFile(repos, tempDir, makeOptions({ outputPath }));
 
-            expect(outputFile).to.equal(outputPath);
-            expect(fs.existsSync(outputFile)).to.be.true;
+            expect(outputFile).toBe(outputPath);
+            expect(fs.existsSync(outputFile)).toBe(true);
         });
 
         it('should overwrite an existing workspace file', () => {
@@ -152,7 +152,7 @@ describe('workspace-action', () => {
 
             const outputFile = path.join(tempDir, WORKSPACE_FILE_NAME);
             const content: VSCodeWorkspace = JSON.parse(fs.readFileSync(outputFile, 'utf-8'));
-            expect(content.folders).to.have.length(2);
+            expect(content.folders).toHaveLength(2);
         });
     });
 
@@ -160,24 +160,24 @@ describe('workspace-action', () => {
         it('should find a single .code-workspace file', () => {
             fs.writeFileSync(path.join(tempDir, 'glsp.code-workspace'), '{}');
             const result = discoverWorkspaceFile(tempDir);
-            expect(result).to.equal(path.join(tempDir, 'glsp.code-workspace'));
+            expect(result).toBe(path.join(tempDir, 'glsp.code-workspace'));
         });
 
         it('should return undefined when no .code-workspace file exists', () => {
             const result = discoverWorkspaceFile(tempDir);
-            expect(result).to.be.undefined;
+            expect(result).toBeUndefined();
         });
 
         it('should prefer glsp.code-workspace when multiple exist', () => {
             fs.writeFileSync(path.join(tempDir, 'glsp.code-workspace'), '{}');
             fs.writeFileSync(path.join(tempDir, 'other.code-workspace'), '{}');
             const result = discoverWorkspaceFile(tempDir);
-            expect(result).to.equal(path.join(tempDir, 'glsp.code-workspace'));
+            expect(result).toBe(path.join(tempDir, 'glsp.code-workspace'));
         });
 
         it('should return undefined for nonexistent directory', () => {
             const result = discoverWorkspaceFile(path.join(tempDir, 'nonexistent'));
-            expect(result).to.be.undefined;
+            expect(result).toBeUndefined();
         });
     });
 });
diff --git a/dev-packages/cli/src/commands/update-next.spec.ts b/dev-packages/cli/src/commands/update-next.spec.ts
index 21a1335..52ef101 100644
--- a/dev-packages/cli/src/commands/update-next.spec.ts
+++ b/dev-packages/cli/src/commands/update-next.spec.ts
@@ -81,14 +81,14 @@ describe('updateNext', () => {
         const yamlDuringInstall = await runAndCaptureWorkspaceYaml(workspaceYamlPath);
 
         // the resolved next version is pinned via the overrides block while installing ...
-        expect(YAML.parse(yamlDuringInstall).overrides).to.deep.equal({ '@eclipse-glsp/protocol': '2.8.0-next.6' });
+        expect(YAML.parse(yamlDuringInstall).overrides).toEqual({ '@eclipse-glsp/protocol': '2.8.0-next.6' });
         // ... and the file is restored verbatim afterwards
-        expect(fs.readFileSync(workspaceYamlPath, 'utf8')).to.equal(originalYaml);
+        expect(fs.readFileSync(workspaceYamlPath, 'utf8')).toBe(originalYaml);
 
         const commands = execAsyncStub.mock.calls.map(call => call[0] as string);
         // uses `pnpm install` (lockfile-respecting), never `pnpm update` (opportunistic in-range bumps)
-        expect(commands.some(cmd => cmd.includes('pnpm install'))).to.be.true;
-        expect(commands.some(cmd => cmd.includes('pnpm update'))).to.be.false;
+        expect(commands.some(cmd => cmd.includes('pnpm install'))).toBe(true);
+        expect(commands.some(cmd => cmd.includes('pnpm update'))).toBe(false);
     });
 
     it('should merge into an existing overrides block (ours win) and restore it afterwards', async () => {
@@ -111,12 +111,12 @@ describe('updateNext', () => {
         const yamlDuringInstall = await runAndCaptureWorkspaceYaml(workspaceYamlPath);
 
         // existing override preserved, our pin merged in / overriding the stale one
-        expect(YAML.parse(yamlDuringInstall).overrides).to.deep.equal({
+        expect(YAML.parse(yamlDuringInstall).overrides).toEqual({
             'unrelated-dep': '1.2.3',
             '@eclipse-glsp/protocol': '2.8.0-next.6'
         });
         // original file restored verbatim
-        expect(fs.readFileSync(workspaceYamlPath, 'utf8')).to.equal(originalYaml);
+        expect(fs.readFileSync(workspaceYamlPath, 'utf8')).toBe(originalYaml);
     });
 
     it('should do nothing when a pnpm repo has no next dependencies', async () => {
diff --git a/dev-packages/cli/src/util/file-util.spec.ts b/dev-packages/cli/src/util/file-util.spec.ts
index 287d97b..9ca72b2 100644
--- a/dev-packages/cli/src/util/file-util.spec.ts
+++ b/dev-packages/cli/src/util/file-util.spec.ts
@@ -38,19 +38,19 @@ describe('file-util', () => {
 
             const result = readFile(filePath, { startLine: 2, endLine: 3 });
 
-            expect(result).to.contain('line2');
-            expect(result).to.contain('line3');
-            expect(result).to.not.contain('line1');
-            expect(result).to.not.contain('line4');
+            expect(result).toContain('line2');
+            expect(result).toContain('line3');
+            expect(result).not.toContain('line1');
+            expect(result).not.toContain('line4');
         });
 
         it('should throw for a non-existent file', () => {
             const filePath = path.join(tempDir, 'missing.txt');
-            expect(() => readFile(filePath)).to.throw(/no such file/);
+            expect(() => readFile(filePath)).toThrow(/no such file/);
         });
 
         it('should throw for a directory path', () => {
-            expect(() => readFile(tempDir)).to.throw(/Is a directory/);
+            expect(() => readFile(tempDir)).toThrow(/Is a directory/);
         });
     });
 
@@ -61,7 +61,7 @@ describe('file-util', () => {
 
             deleteFile(filePath);
 
-            expect(fs.existsSync(filePath)).to.be.false;
+            expect(fs.existsSync(filePath)).toBe(false);
         });
 
         it('should delete a directory recursively', () => {
@@ -71,12 +71,12 @@ describe('file-util', () => {
 
             deleteFile(dirPath);
 
-            expect(fs.existsSync(dirPath)).to.be.false;
+            expect(fs.existsSync(dirPath)).toBe(false);
         });
 
         it('should throw for a non-existent path', () => {
             const filePath = path.join(tempDir, 'no-such-file.txt');
-            expect(() => deleteFile(filePath)).to.throw(/no such file/);
+            expect(() => deleteFile(filePath)).toThrow(/no such file/);
         });
     });
 
@@ -89,8 +89,8 @@ describe('file-util', () => {
 
             moveFile(filePath, destDir);
 
-            expect(fs.existsSync(path.join(destDir, 'source.txt'))).to.be.true;
-            expect(fs.existsSync(filePath)).to.be.false;
+            expect(fs.existsSync(path.join(destDir, 'source.txt'))).toBe(true);
+            expect(fs.existsSync(filePath)).toBe(false);
         });
     });
 
@@ -99,7 +99,7 @@ describe('file-util', () => {
             const filePath = path.join(tempDir, 'bad.json');
             fs.writeFileSync(filePath, '{ not valid json }', 'utf8');
 
-            expect(() => readJson(filePath)).to.throw(/Failed to parse JSON/);
+            expect(() => readJson(filePath)).toThrow(/Failed to parse JSON/);
         });
     });
 
@@ -111,7 +111,7 @@ describe('file-util', () => {
             replaceInFile(filePath, 'world', 'universe');
 
             const result = fs.readFileSync(filePath, 'utf8');
-            expect(result).to.equal('hello universe');
+            expect(result).toBe('hello universe');
         });
 
         it('should replace a regex pattern in a file', () => {
@@ -121,7 +121,7 @@ describe('file-util', () => {
             replaceInFile(filePath, /\d+/, 'NUM');
 
             const result = fs.readFileSync(filePath, 'utf8');
-            expect(result).to.equal('fooNUMbar');
+            expect(result).toBe('fooNUMbar');
         });
     });
 
@@ -134,8 +134,8 @@ describe('file-util', () => {
 
             const result = filterFiles([matchFile, noMatchFile], 'hello');
 
-            expect(result).to.have.lengthOf(1);
-            expect(result[0]).to.equal(path.resolve(matchFile));
+            expect(result).toHaveLength(1);
+            expect(result[0]).toBe(path.resolve(matchFile));
         });
     });
 });
diff --git a/dev-packages/cli/src/util/git-util.spec.ts b/dev-packages/cli/src/util/git-util.spec.ts
index 821048a..fb554dd 100644
--- a/dev-packages/cli/src/util/git-util.spec.ts
+++ b/dev-packages/cli/src/util/git-util.spec.ts
@@ -37,49 +37,49 @@ describe('git-util', () => {
         it('should parse porcelain output into file paths', () => {
             execStub.mockReturnValue(' M src/file.ts\n?? new-file.ts');
             const result = getUncommittedChanges('/repo');
-            expect(result).to.have.length(2);
+            expect(result).toHaveLength(2);
         });
 
         it('should return empty array for empty output', () => {
             execStub.mockReturnValue('');
             const result = getUncommittedChanges('/repo');
-            expect(result).to.have.length(0);
+            expect(result).toHaveLength(0);
         });
     });
 
     describe('hasChanges', () => {
         it('should return true when there are uncommitted changes', () => {
             execStub.mockReturnValue(' M src/file.ts\n?? new-file.ts');
-            expect(hasChanges('/repo')).to.be.true;
+            expect(hasChanges('/repo')).toBe(true);
         });
 
         it('should return false when there are no changes', () => {
             execStub.mockReturnValue('');
-            expect(hasChanges('/repo')).to.be.false;
+            expect(hasChanges('/repo')).toBe(false);
         });
     });
 
     describe('commitChanges', () => {
         it('should escape double quotes in commit message', () => {
             commitChanges('fix "bug"', '/repo');
-            expect(execStub.mock.calls[1][0]).to.contain('\\"');
+            expect(execStub.mock.calls[1][0]).toContain('\\"');
         });
 
         it('should escape backslashes in commit message', () => {
             commitChanges('path\\to\\file', '/repo');
-            expect(execStub.mock.calls[1][0]).to.contain('\\\\');
+            expect(execStub.mock.calls[1][0]).toContain('\\\\');
         });
     });
 
     describe('getDefaultBranch', () => {
         it('should parse HEAD branch from remote output', () => {
             execStub.mockReturnValue('* remote origin\n  HEAD branch: main\n  Remote branches:');
-            expect(getDefaultBranch('/repo')).to.equal('main');
+            expect(getDefaultBranch('/repo')).toBe('main');
         });
 
         it('should fallback to master when HEAD branch is not found', () => {
             execStub.mockReturnValue('* remote origin\n  Remote branches:');
-            expect(getDefaultBranch('/repo')).to.equal('master');
+            expect(getDefaultBranch('/repo')).toBe('master');
         });
     });
 
@@ -89,7 +89,7 @@ describe('git-util', () => {
                 if (/symbolic-ref/.test(cmd)) return 'origin/develop';
                 return '';
             });
-            expect(getDefaultBranchRef('/repo')).to.equal('origin/develop');
+            expect(getDefaultBranchRef('/repo')).toBe('origin/develop');
         });
 
         it('should fall back to the first existing candidate ref', () => {
@@ -100,14 +100,14 @@ describe('git-util', () => {
                 if (/--verify --quiet main/.test(cmd)) return '';
                 return '';
             });
-            expect(getDefaultBranchRef('/repo')).to.equal('main');
+            expect(getDefaultBranchRef('/repo')).toBe('main');
         });
 
         it('should return undefined when no default branch can be determined', () => {
             execStub.mockImplementation(() => {
                 throw new Error('not a git repository');
             });
-            expect(getDefaultBranchRef('/repo')).to.be.undefined;
+            expect(getDefaultBranchRef('/repo')).toBeUndefined();
         });
     });
 
@@ -120,8 +120,8 @@ describe('git-util', () => {
                 return '';
             });
             const result = getChangesComparedToDefaultBranch('/repo');
-            expect(result).to.have.members(['/repo/src/a.ts', '/repo/src/b.ts', '/repo/src/c.ts']);
-            expect(result).to.have.length(3);
+            expect(result).toEqual(expect.arrayContaining(['/repo/src/a.ts', '/repo/src/b.ts', '/repo/src/c.ts']));
+            expect(result).toHaveLength(3);
         });
 
         it('should only consider uncommitted changes when no default branch is found', () => {
@@ -130,7 +130,7 @@ describe('git-util', () => {
                 throw new Error('not a git repository');
             });
             const result = getChangesComparedToDefaultBranch('/repo');
-            expect(result).to.deep.equal(['/repo/src/only.ts']);
+            expect(result).toEqual(['/repo/src/only.ts']);
         });
     });
 
@@ -138,13 +138,13 @@ describe('git-util', () => {
         it('should return a Date for a valid date string', () => {
             execStub.mockReturnValue('2024-01-15 10:30:00 +0000');
             const result = getLastModificationDate('file.ts', '/repo');
-            expect(result).to.be.an.instanceOf(Date);
+            expect(result).toBeInstanceOf(Date);
         });
 
         it('should return undefined for empty result', () => {
             execStub.mockReturnValue('');
             const result = getLastModificationDate('file.ts', '/repo');
-            expect(result).to.be.undefined;
+            expect(result).toBeUndefined();
         });
 
         it('should return undefined when exec throws', () => {
@@ -152,7 +152,7 @@ describe('git-util', () => {
                 throw new Error('git error');
             });
             const result = getLastModificationDate('file.ts', '/repo');
-            expect(result).to.be.undefined;
+            expect(result).toBeUndefined();
         });
     });
 });
diff --git a/dev-packages/cli/src/util/glsp-repo-util.spec.ts b/dev-packages/cli/src/util/glsp-repo-util.spec.ts
index 5d3e8e7..93494c3 100644
--- a/dev-packages/cli/src/util/glsp-repo-util.spec.ts
+++ b/dev-packages/cli/src/util/glsp-repo-util.spec.ts
@@ -23,31 +23,31 @@ describe('repo-filter', () => {
 
         it('should return configured repos when no filter is specified', () => {
             const result = resolveRepoFilter(configuredRepos, {});
-            expect(result).to.deep.equal(configuredRepos);
+            expect(result).toEqual(configuredRepos);
         });
 
         it('should filter to specific repos with --repo', () => {
             const result = resolveRepoFilter(configuredRepos, { repo: ['glsp-client'] });
-            expect(result).to.deep.equal(['glsp-client']);
+            expect(result).toEqual(['glsp-client']);
         });
 
         it('should allow repos not in config with --repo', () => {
             const result = resolveRepoFilter(configuredRepos, { repo: ['glsp-playwright'] });
-            expect(result).to.deep.equal(['glsp-playwright']);
+            expect(result).toEqual(['glsp-playwright']);
         });
 
         it('should expand preset with --preset', () => {
             const result = resolveRepoFilter(configuredRepos, { preset: 'core' });
-            expect(result).to.include('glsp-client');
-            expect(result).to.include('glsp-server-node');
+            expect(result).toContain('glsp-client');
+            expect(result).toContain('glsp-server-node');
         });
 
         it('should throw for unknown preset', () => {
-            expect(() => resolveRepoFilter(configuredRepos, { preset: 'nonexistent' })).to.throw(/Unknown preset/);
+            expect(() => resolveRepoFilter(configuredRepos, { preset: 'nonexistent' })).toThrow(/Unknown preset/);
         });
 
         it('should throw for unknown repo name', () => {
-            expect(() => resolveRepoFilter(configuredRepos, { repo: ['not-a-repo'] })).to.throw(/Unknown repository/);
+            expect(() => resolveRepoFilter(configuredRepos, { repo: ['not-a-repo'] })).toThrow(/Unknown repository/);
         });
     });
 });
diff --git a/dev-packages/cli/src/util/package-util.spec.ts b/dev-packages/cli/src/util/package-util.spec.ts
index adc9612..0ee686a 100644
--- a/dev-packages/cli/src/util/package-util.spec.ts
+++ b/dev-packages/cli/src/util/package-util.spec.ts
@@ -38,19 +38,19 @@ describe('package-util', () => {
         });
 
         it('should throw if the path does not point to a package.json file', () => {
-            expect(() => new PackageHelper(path.join(tempDir, 'other.json'), 'test')).to.throw(/must point to a package.json/);
+            expect(() => new PackageHelper(path.join(tempDir, 'other.json'), 'test')).toThrow(/must point to a package.json/);
         });
 
         it('should throw if the package.json file does not exist', () => {
-            expect(() => new PackageHelper(path.join(tempDir, 'package.json'), 'test')).to.throw(/No package.json found/);
+            expect(() => new PackageHelper(path.join(tempDir, 'package.json'), 'test')).toThrow(/No package.json found/);
         });
 
         it('should succeed when the path points to an existing package.json', () => {
             const packageJsonPath = path.join(tempDir, 'package.json');
             fs.writeFileSync(packageJsonPath, JSON.stringify({ name: 'test-pkg', version: '1.0.0' }));
             const helper = new PackageHelper(packageJsonPath, 'test-pkg');
-            expect(helper.filePath).to.equal(packageJsonPath);
-            expect(helper.name).to.equal('test-pkg');
+            expect(helper.filePath).toBe(packageJsonPath);
+            expect(helper.name).toBe('test-pkg');
         });
     });
 
@@ -84,8 +84,8 @@ describe('package-util', () => {
             vi.spyOn(processUtil, 'exec').mockReturnValue(listOutput);
 
             const packages = getWorkspacePackages(tempDir);
-            expect(packages.map(pkg => pkg.name)).to.deep.equal(['@scope/pkg-a', '@scope/pkg-b']);
-            expect(packages.map(pkg => pkg.location)).to.deep.equal([pkgADir, pkgBDir]);
+            expect(packages.map(pkg => pkg.name)).toEqual(['@scope/pkg-a', '@scope/pkg-b']);
+            expect(packages.map(pkg => pkg.location)).toEqual([pkgADir, pkgBDir]);
         });
 
         it('should append the root package if includeRoot is set', () => {
@@ -98,8 +98,8 @@ describe('package-util', () => {
             vi.spyOn(processUtil, 'exec').mockReturnValue(listOutput);
 
             const packages = getWorkspacePackages(tempDir, true);
-            expect(packages.map(pkg => pkg.name)).to.deep.equal(['@scope/pkg-a', 'root']);
-            expect(packages[packages.length - 1].location).to.equal(tempDir);
+            expect(packages.map(pkg => pkg.name)).toEqual(['@scope/pkg-a', 'root']);
+            expect(packages[packages.length - 1].location).toBe(tempDir);
         });
     });
 });
diff --git a/dev-packages/cli/src/util/process-util.spec.ts b/dev-packages/cli/src/util/process-util.spec.ts
index bf57c3f..d8eb875 100644
--- a/dev-packages/cli/src/util/process-util.spec.ts
+++ b/dev-packages/cli/src/util/process-util.spec.ts
@@ -25,25 +25,25 @@ describe('process-util', () => {
     describe('exec', () => {
         it('should return trimmed stdout on success', () => {
             const result = exec('echo hello');
-            expect(result).to.equal('hello');
+            expect(result).toBe('hello');
         });
 
         it('should throw on non-zero exit code', () => {
-            expect(() => exec('sh -c "exit 1"')).to.throw(/Command failed/);
+            expect(() => exec('sh -c "exit 1"')).toThrow(/Command failed/);
         });
 
         it('should use custom error message when provided', () => {
-            expect(() => exec('sh -c "exit 1"', { errorMsg: 'Custom error' })).to.throw('Custom error');
+            expect(() => exec('sh -c "exit 1"', { errorMsg: 'Custom error' })).toThrow('Custom error');
         });
 
         it('should pass cwd option', () => {
             const result = exec('pwd', { cwd: '/tmp' });
-            expect(result).to.include('tmp');
+            expect(result).toContain('tmp');
         });
 
         it('should return empty string for command with no output', () => {
             const result = exec('true');
-            expect(result).to.equal('');
+            expect(result).toBe('');
         });
     });
 
@@ -57,7 +57,7 @@ describe('process-util', () => {
                 await execForeground('sh -c "exit 1"');
                 expect.fail('should have thrown');
             } catch (error) {
-                expect((error as Error).message).to.contain('exited with code 1');
+                expect((error as Error).message).toContain('exited with code 1');
             }
         });
 
diff --git a/dev-packages/cli/src/util/validation-util.spec.ts b/dev-packages/cli/src/util/validation-util.spec.ts
index 5594b3d..c51955d 100644
--- a/dev-packages/cli/src/util/validation-util.spec.ts
+++ b/dev-packages/cli/src/util/validation-util.spec.ts
@@ -35,25 +35,25 @@ describe('validation-util', () => {
     describe('validateDirectory', () => {
         it('should return the resolved path for a valid directory', () => {
             const result = validateDirectory(tempDir);
-            expect(result).to.equal(path.resolve(tempDir));
+            expect(result).toBe(path.resolve(tempDir));
         });
 
         it('should throw for a non-existent path', () => {
             const nonExistent = path.join(tempDir, 'does-not-exist');
-            expect(() => validateDirectory(nonExistent)).to.throw(/Not a valid file path/);
+            expect(() => validateDirectory(nonExistent)).toThrow(/Not a valid file path/);
         });
 
         it('should throw for a file path (not a directory)', () => {
             const filePath = path.join(tempDir, 'test-file.txt');
             fs.writeFileSync(filePath, 'content');
-            expect(() => validateDirectory(filePath)).to.throw(/Not a directory/);
+            expect(() => validateDirectory(filePath)).toThrow(/Not a directory/);
         });
     });
 
     describe('validateFile', () => {
         it('should throw for a non-existent file when hasToExist is true', () => {
             const nonExistent = path.join(tempDir, 'missing-file.txt');
-            expect(() => validateFile(nonExistent, true)).to.throw(/Not a valid file path/);
+            expect(() => validateFile(nonExistent, true)).toThrow(/Not a valid file path/);
         });
     });
 
@@ -62,12 +62,12 @@ describe('validation-util', () => {
             vi.spyOn(gitUtil, 'isGitRepository').mockReturnValue(true);
             vi.spyOn(gitUtil, 'getGitRoot').mockReturnValue('/resolved/root');
             const result = validateGitDirectory(tempDir);
-            expect(result).to.equal('/resolved/root');
+            expect(result).toBe('/resolved/root');
         });
 
         it('should throw for a directory that is not a git repository', () => {
             vi.spyOn(gitUtil, 'isGitRepository').mockReturnValue(false);
-            expect(() => validateGitDirectory(tempDir)).to.throw(/Not a valid git repository/);
+            expect(() => validateGitDirectory(tempDir)).toThrow(/Not a valid git repository/);
         });
     });
 });
diff --git a/dev-packages/cli/tests/e2e/check-header.e2e.spec.ts b/dev-packages/cli/tests/e2e/check-header.e2e.spec.ts
index 7e464d5..2a98f97 100644
--- a/dev-packages/cli/tests/e2e/check-header.e2e.spec.ts
+++ b/dev-packages/cli/tests/e2e/check-header.e2e.spec.ts
@@ -53,32 +53,32 @@ describe('checkHeaders e2e', () => {
     it('should pass for files with valid headers', () => {
         commitFile(repoDir, 'src/good.ts', VALID_HEADER + '\nconst x = 1;\n', 'add valid file');
         const result = runCli(['checkHeaders', repoDir]);
-        expect(result.exitCode).to.equal(0);
-        expect(result.stdout).to.contain('0 copyright header violations');
+        expect(result.exitCode).toBe(0);
+        expect(result.stdout).toContain('0 copyright header violations');
     });
 
     it('should detect files with missing headers', () => {
         commitFile(repoDir, 'src/bad.ts', 'const x = 1;\n', 'add file without header');
         const result = runCli(['checkHeaders', repoDir]);
-        expect(result.exitCode).to.not.equal(0);
+        expect(result.exitCode).not.toBe(0);
     });
 
     it('should auto-fix invalid headers with --autoFix', () => {
         const outdatedHeader = VALID_HEADER.replace(String(new Date().getFullYear()), '2020');
         commitFile(repoDir, 'src/outdated.ts', outdatedHeader + '\nconst x = 1;\n', 'add outdated file');
         const result = runCli(['checkHeaders', repoDir, '--autoFix']);
-        expect(result.exitCode).to.equal(0);
+        expect(result.exitCode).toBe(0);
         const content = fs.readFileSync(path.join(repoDir, 'src/outdated.ts'), 'utf8');
-        expect(content).to.contain(String(new Date().getFullYear()));
+        expect(content).toContain(String(new Date().getFullYear()));
     });
 
     it('should create a git commit with --autoFix --commit', () => {
         const outdatedHeader = VALID_HEADER.replace(String(new Date().getFullYear()), '2020');
         commitFile(repoDir, 'src/outdated.ts', outdatedHeader + '\nconst x = 1;\n', 'add outdated file');
         const result = runCli(['checkHeaders', repoDir, '--autoFix', '--commit']);
-        expect(result.exitCode).to.equal(0);
+        expect(result.exitCode).toBe(0);
         const log = execSync('git log --oneline', { cwd: repoDir, encoding: 'utf-8' });
-        expect(log).to.contain('Fix copyright header violations');
+        expect(log).toContain('Fix copyright header violations');
     });
 
     it('should only check changed files with --type changes', () => {
@@ -87,7 +87,7 @@ describe('checkHeaders e2e', () => {
         fs.writeFileSync(path.join(repoDir, 'src/new.ts'), 'const y = 2;\n');
         execSync('git add .', { cwd: repoDir });
         const result = runCli(['checkHeaders', repoDir, '--type', 'changes']);
-        expect(result.stdout).to.contain('1 copyright header violations');
+        expect(result.stdout).toContain('1 copyright header violations');
     });
 
     it('should check files changed against the default branch with --type changes', () => {
@@ -96,16 +96,16 @@ describe('checkHeaders e2e', () => {
         execSync('git checkout -b feature', { cwd: repoDir });
         commitFile(repoDir, 'src/feature.ts', 'const y = 2;\n', 'add feature file');
         const result = runCli(['checkHeaders', repoDir, '--type', 'changes']);
-        expect(result.stdout).to.contain('Check copy right headers of 1 files');
-        expect(result.stdout).to.contain('feature.ts');
-        expect(result.stdout).to.not.contain('base.ts');
+        expect(result.stdout).toContain('Check copy right headers of 1 files');
+        expect(result.stdout).toContain('feature.ts');
+        expect(result.stdout).not.toContain('base.ts');
     });
 
     it('should only check last commit files with --type lastCommit', () => {
         commitFile(repoDir, 'src/old.ts', VALID_HEADER + '\nconst x = 1;\n', 'add old file');
         commitFile(repoDir, 'src/new.ts', 'const y = 2;\n', 'add new file');
         const result = runCli(['checkHeaders', repoDir, '--type', 'lastCommit']);
-        expect(result.stdout).to.contain('Check copy right headers of 1 files');
+        expect(result.stdout).toContain('Check copy right headers of 1 files');
     });
 
     describe('with a repository under a dot-directory', () => {
@@ -126,16 +126,16 @@ describe('checkHeaders e2e', () => {
             execSync('git checkout -b feature', { cwd: hiddenRepoDir });
             commitFile(hiddenRepoDir, 'src/feature.ts', 'const y = 2;\n', 'add feature file');
             const result = runCli(['checkHeaders', hiddenRepoDir, '--type', 'changes']);
-            expect(result.stdout).to.contain('Check copy right headers of 1 files');
-            expect(result.stdout).to.contain('feature.ts');
-            expect(result.stdout).to.not.contain('base.ts');
+            expect(result.stdout).toContain('Check copy right headers of 1 files');
+            expect(result.stdout).toContain('feature.ts');
+            expect(result.stdout).not.toContain('base.ts');
         });
 
         it('should still detect changed files with --type lastCommit', () => {
             commitFile(hiddenRepoDir, 'src/old.ts', VALID_HEADER + '\nconst x = 1;\n', 'add old file');
             commitFile(hiddenRepoDir, 'src/new.ts', 'const y = 2;\n', 'add new file');
             const result = runCli(['checkHeaders', hiddenRepoDir, '--type', 'lastCommit']);
-            expect(result.stdout).to.contain('Check copy right headers of 1 files');
+            expect(result.stdout).toContain('Check copy right headers of 1 files');
         });
     });
 
@@ -143,29 +143,29 @@ describe('checkHeaders e2e', () => {
         commitFile(repoDir, 'src/script.js', 'const x = 1;\n', 'add js file');
         commitFile(repoDir, 'src/good.ts', VALID_HEADER + '\nconst y = 2;\n', 'add ts file');
         const result = runCli(['checkHeaders', repoDir, '--fileExtensions', 'js']);
-        expect(result.stdout).to.contain('Check copy right headers of 1 files');
+        expect(result.stdout).toContain('Check copy right headers of 1 files');
     });
 
     it('should exclude files matching --exclude pattern', () => {
         commitFile(repoDir, 'src/main.ts', 'const x = 1;\n', 'add main');
         commitFile(repoDir, 'src/generated/output.ts', 'const y = 2;\n', 'add generated');
         const result = runCli(['checkHeaders', repoDir, '--exclude', '**/generated/**']);
-        expect(result.stdout).to.not.contain('generated/output.ts');
+        expect(result.stdout).not.toContain('generated/output.ts');
     });
 
     it('should accept --no-exclude-defaults flag', () => {
         commitFile(repoDir, 'src/main.ts', VALID_HEADER + '\nconst y = 2;\n', 'add main');
         const result = runCli(['checkHeaders', repoDir, '--no-exclude-defaults']);
-        expect(result.exitCode).to.equal(0);
+        expect(result.exitCode).toBe(0);
     });
 
     it('should write results to JSON file with --json', () => {
         commitFile(repoDir, 'src/good.ts', VALID_HEADER + '\nconst x = 1;\n', 'add valid file');
         const result = runCli(['checkHeaders', repoDir, '--json']);
-        expect(result.exitCode).to.equal(0);
+        expect(result.exitCode).toBe(0);
         const jsonPath = path.join(repoDir, 'headerCheck.json');
-        expect(fs.existsSync(jsonPath)).to.equal(true);
+        expect(fs.existsSync(jsonPath)).toBe(true);
         const jsonContent = JSON.parse(fs.readFileSync(jsonPath, 'utf8'));
-        expect(jsonContent).to.be.an('array');
+        expect(Array.isArray(jsonContent)).toBe(true);
     });
 });
diff --git a/dev-packages/cli/tests/e2e/generate-index.e2e.spec.ts b/dev-packages/cli/tests/e2e/generate-index.e2e.spec.ts
index 94d29f6..c5c81e0 100644
--- a/dev-packages/cli/tests/e2e/generate-index.e2e.spec.ts
+++ b/dev-packages/cli/tests/e2e/generate-index.e2e.spec.ts
@@ -35,18 +35,18 @@ describe('generateIndex e2e', () => {
         fs.writeFileSync(path.join(tempDir, 'foo.ts'), 'export const foo = 1;\n');
         fs.writeFileSync(path.join(tempDir, 'bar.ts'), 'export const bar = 2;\n');
         const result = runCli(['generateIndex', tempDir, '--forceOverwrite']);
-        expect(result.exitCode).to.equal(0);
+        expect(result.exitCode).toBe(0);
         const indexContent = fs.readFileSync(path.join(tempDir, 'index.ts'), 'utf8');
-        expect(indexContent).to.contain("export * from './bar';");
-        expect(indexContent).to.contain("export * from './foo';");
+        expect(indexContent).toContain("export * from './bar';");
+        expect(indexContent).toContain("export * from './foo';");
     });
 
     it('should use ESM style exports with --style esm', () => {
         fs.writeFileSync(path.join(tempDir, 'module.ts'), 'export const m = 1;\n');
         const result = runCli(['generateIndex', tempDir, '--forceOverwrite', '--style', 'esm']);
-        expect(result.exitCode).to.equal(0);
+        expect(result.exitCode).toBe(0);
         const indexContent = fs.readFileSync(path.join(tempDir, 'index.ts'), 'utf8');
-        expect(indexContent).to.contain("export * from './module.js';");
+        expect(indexContent).toContain("export * from './module.js';");
     });
 
     it('should generate nested indices without --singleIndex', () => {
@@ -55,9 +55,9 @@ describe('generateIndex e2e', () => {
         fs.writeFileSync(path.join(subDir, 'nested.ts'), 'export const n = 1;\n');
         fs.writeFileSync(path.join(tempDir, 'root.ts'), 'export const r = 1;\n');
         const result = runCli(['generateIndex', tempDir, '--forceOverwrite']);
-        expect(result.exitCode).to.equal(0);
-        expect(fs.existsSync(path.join(tempDir, 'index.ts'))).to.equal(true);
-        expect(fs.existsSync(path.join(subDir, 'index.ts'))).to.equal(true);
+        expect(result.exitCode).toBe(0);
+        expect(fs.existsSync(path.join(tempDir, 'index.ts'))).toBe(true);
+        expect(fs.existsSync(path.join(subDir, 'index.ts'))).toBe(true);
     });
 
     it('should generate a single root index with --singleIndex', () => {
@@ -66,29 +66,29 @@ describe('generateIndex e2e', () => {
         fs.writeFileSync(path.join(subDir, 'nested.ts'), 'export const n = 1;\n');
         fs.writeFileSync(path.join(tempDir, 'root.ts'), 'export const r = 1;\n');
         const result = runCli(['generateIndex', tempDir, '--forceOverwrite', '--singleIndex']);
-        expect(result.exitCode).to.equal(0);
-        expect(fs.existsSync(path.join(tempDir, 'index.ts'))).to.equal(true);
-        expect(fs.existsSync(path.join(subDir, 'index.ts'))).to.equal(false);
+        expect(result.exitCode).toBe(0);
+        expect(fs.existsSync(path.join(tempDir, 'index.ts'))).toBe(true);
+        expect(fs.existsSync(path.join(subDir, 'index.ts'))).toBe(false);
     });
 
     it('should only index files matching custom --match pattern', () => {
         fs.writeFileSync(path.join(tempDir, 'code.ts'), 'export const c = 1;\n');
         fs.writeFileSync(path.join(tempDir, 'script.js'), 'export const s = 1;\n');
         const result = runCli(['generateIndex', tempDir, '--forceOverwrite', '--match', '**/*.js']);
-        expect(result.exitCode).to.equal(0);
+        expect(result.exitCode).toBe(0);
         const indexContent = fs.readFileSync(path.join(tempDir, 'index.ts'), 'utf8');
-        expect(indexContent).to.contain("'./script'");
-        expect(indexContent).to.not.contain("'./code'");
+        expect(indexContent).toContain("'./script'");
+        expect(indexContent).not.toContain("'./code'");
     });
 
     it('should exclude files matching custom --ignore pattern', () => {
         fs.writeFileSync(path.join(tempDir, 'keep.ts'), 'export const k = 1;\n');
         fs.writeFileSync(path.join(tempDir, 'skip.test.ts'), 'export const s = 1;\n');
         const result = runCli(['generateIndex', tempDir, '--forceOverwrite', '--ignore', '**/*.test.ts']);
-        expect(result.exitCode).to.equal(0);
+        expect(result.exitCode).toBe(0);
         const indexContent = fs.readFileSync(path.join(tempDir, 'index.ts'), 'utf8');
-        expect(indexContent).to.contain("'./keep'");
-        expect(indexContent).to.not.contain("'./skip.test'");
+        expect(indexContent).toContain("'./keep'");
+        expect(indexContent).not.toContain("'./skip.test'");
     });
 
     it('should respect .indexignore file', () => {
@@ -96,17 +96,17 @@ describe('generateIndex e2e', () => {
         fs.writeFileSync(path.join(tempDir, 'excluded.ts'), 'export const e = 1;\n');
         fs.writeFileSync(path.join(tempDir, '.indexignore'), 'excluded.ts\n');
         const result = runCli(['generateIndex', tempDir, '--forceOverwrite']);
-        expect(result.exitCode).to.equal(0);
+        expect(result.exitCode).toBe(0);
         const indexContent = fs.readFileSync(path.join(tempDir, 'index.ts'), 'utf8');
-        expect(indexContent).to.contain("'./included'");
-        expect(indexContent).to.not.contain("'./excluded'");
+        expect(indexContent).toContain("'./included'");
+        expect(indexContent).not.toContain("'./excluded'");
     });
 
     it('should produce extra output with --verbose', () => {
         fs.writeFileSync(path.join(tempDir, 'mod.ts'), 'export const m = 1;\n');
         const result = runCli(['generateIndex', tempDir, '--forceOverwrite', '--verbose']);
-        expect(result.exitCode).to.equal(0);
+        expect(result.exitCode).toBe(0);
         const output = result.stdout + result.stderr;
-        expect(output).to.contain('generateIndex');
+        expect(output).toContain('generateIndex');
     });
 });
diff --git a/dev-packages/cli/tests/e2e/releng/prepare.e2e.spec.ts b/dev-packages/cli/tests/e2e/releng/prepare.e2e.spec.ts
index 2f44b13..bd94200 100644
--- a/dev-packages/cli/tests/e2e/releng/prepare.e2e.spec.ts
+++ b/dev-packages/cli/tests/e2e/releng/prepare.e2e.spec.ts
@@ -155,30 +155,30 @@ describe('releng prepare — glsp', function () {
         const result = runCli(['releng', 'prepare', 'custom', '99.0.0', '--no-push', '--no-check', '-r', repoDir], {
             timeout: 0
         });
-        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).to.equal(0);
+        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).toBe(0);
 
         // Release branch created
         const branches = git('branch', repoDir);
-        expect(branches).to.contain('release-v99.0.0');
+        expect(branches).toContain('release-v99.0.0');
 
         // Version bumped in root package.json
         const rootPkg = readJson(path.join(repoDir, 'package.json'));
-        expect(rootPkg.version).to.equal('99.0.0');
+        expect(rootPkg.version).toBe('99.0.0');
 
         // At least one workspace package.json updated
         const workspacePkgs = findWorkspacePackageJsons(repoDir);
-        expect(workspacePkgs.length).to.be.greaterThan(0);
+        expect(workspacePkgs.length).toBeGreaterThan(0);
         const firstPkg = readJson(workspacePkgs[0]);
-        expect(firstPkg.version).to.equal('99.0.0');
+        expect(firstPkg.version).toBe('99.0.0');
 
         // CHANGELOG.md updated
         const changelog = readText(path.join(repoDir, 'CHANGELOG.md'));
-        expect(changelog).to.not.contain('## v99.0.0 - active');
-        expect(changelog).to.contain('## [v99.0.0 -');
+        expect(changelog).not.toContain('## v99.0.0 - active');
+        expect(changelog).toContain('## [v99.0.0 -');
 
         // Git commit created
         const logMsg = git('log -1 --pretty=%s', repoDir);
-        expect(logMsg).to.equal('v99.0.0');
+        expect(logMsg).toBe('v99.0.0');
     });
 });
 
@@ -218,29 +218,29 @@ for (const repo of NPM_REPOS_WITH_EXTERNAL_DEPS) {
             const result = runCli(['releng', 'prepare', 'next', '--no-push', '--no-check', '-r', repoDir], {
                 timeout: 0
             });
-            expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).to.equal(0);
+            expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).toBe(0);
 
             // Nightly branch created (nightly-X.Y.0-next)
             const branches = git('branch', repoDir);
-            expect(branches).to.match(/nightly-\d+\.\d+\.0-next/);
+            expect(branches).toMatch(/nightly-\d+\.\d+\.0-next/);
 
             // Version bumped with -next suffix
             const rootPkg = readJson(path.join(repoDir, 'package.json'));
-            expect(rootPkg.version as string).to.match(/-next$/);
+            expect(rootPkg.version as string).toMatch(/-next$/);
 
             // At least one workspace package.json updated
             const workspacePkgs = findWorkspacePackageJsons(repoDir);
-            expect(workspacePkgs.length).to.be.greaterThan(0);
+            expect(workspacePkgs.length).toBeGreaterThan(0);
             const firstPkg = readJson(workspacePkgs[0]);
-            expect(firstPkg.version as string).to.match(/-next$/);
+            expect(firstPkg.version as string).toMatch(/-next$/);
 
             // CHANGELOG.md should have a new active section
             const changelog = readText(path.join(repoDir, 'CHANGELOG.md'));
-            expect(changelog).to.match(/## v\d+\.\d+\.0 - active/);
+            expect(changelog).toMatch(/## v\d+\.\d+\.0 - active/);
 
             // Git commit message
             const logMsg = git('log -1 --pretty=%s', repoDir);
-            expect(logMsg).to.match(/^Switch to nightly \d+\.\d+\.0-next versions$/);
+            expect(logMsg).toMatch(/^Switch to nightly \d+\.\d+\.0-next versions$/);
         });
     });
 }
@@ -273,23 +273,23 @@ describe('releng prepare — glsp-playwright', function () {
         const result = runCli(['releng', 'prepare', 'next', '--no-push', '--no-check', '-r', repoDir], {
             timeout: 0
         });
-        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).to.equal(0);
+        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).toBe(0);
 
         // Nightly branch created
         const branches = git('branch', repoDir);
-        expect(branches).to.match(/nightly-\d+\.\d+\.0-next/);
+        expect(branches).toMatch(/nightly-\d+\.\d+\.0-next/);
 
         // Version bumped with -next suffix
         const rootPkg = readJson(path.join(repoDir, 'package.json'));
-        expect(rootPkg.version as string).to.match(/-next$/);
+        expect(rootPkg.version as string).toMatch(/-next$/);
 
         // CHANGELOG.md should have a new active section
         const changelog = readText(path.join(repoDir, 'CHANGELOG.md'));
-        expect(changelog).to.match(/## v\d+\.\d+\.0 - active/);
+        expect(changelog).toMatch(/## v\d+\.\d+\.0 - active/);
 
         // Git commit message
         const logMsg = git('log -1 --pretty=%s', repoDir);
-        expect(logMsg).to.match(/^Switch to nightly \d+\.\d+\.0-next versions$/);
+        expect(logMsg).toMatch(/^Switch to nightly \d+\.\d+\.0-next versions$/);
     });
 });
 
@@ -322,11 +322,11 @@ describe('releng prepare — glsp-client (extended)', function () {
         const result = runCli(['releng', 'prepare', 'next', '--no-push', '--no-check', '--verbose', '-r', repoDir], {
             timeout: 0
         });
-        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).to.equal(0);
+        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).toBe(0);
 
         // Verbose mode produces debug output
         const combined = result.stdout + result.stderr;
-        expect(combined).to.contain('Bump version');
+        expect(combined).toContain('Bump version');
     });
 
     it('should push --draft release to local bare remote', function () {
@@ -338,10 +338,10 @@ describe('releng prepare — glsp-client (extended)', function () {
 
         // gh pr create will fail, so exit code is non-zero. But verify push happened.
         const remoteBranches = git('branch', bareDir);
-        expect(remoteBranches).to.match(/nightly-\d+\.\d+\.0-next/);
+        expect(remoteBranches).toMatch(/nightly-\d+\.\d+\.0-next/);
 
         // Regardless of exit code, the test exercises the push + draft path
-        expect(result).to.not.equal(undefined);
+        expect(result).not.toBe(undefined);
     });
 });
 
@@ -373,27 +373,27 @@ describe('releng prepare — glsp-theia-integration', function () {
         const result = runCli(['releng', 'prepare', 'next', '--no-push', '--no-check', '-r', repoDir], {
             timeout: 0
         });
-        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).to.equal(0);
+        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).toBe(0);
 
         // Nightly branch created
         const branches = git('branch', repoDir);
-        expect(branches).to.match(/nightly-\d+\.\d+\.0-next/);
+        expect(branches).toMatch(/nightly-\d+\.\d+\.0-next/);
 
         // NPM checks
         const rootPkg = readJson(path.join(repoDir, 'package.json'));
-        expect(rootPkg.version as string).to.match(/-next$/);
+        expect(rootPkg.version as string).toMatch(/-next$/);
 
         // Theia README compatibility table should contain 'next'
         const readme = readText(path.join(repoDir, 'README.md'));
-        expect(readme).to.contain('next');
+        expect(readme).toContain('next');
 
         // CHANGELOG.md should have a new active section
         const changelog = readText(path.join(repoDir, 'CHANGELOG.md'));
-        expect(changelog).to.match(/## v\d+\.\d+\.0 - active/);
+        expect(changelog).toMatch(/## v\d+\.\d+\.0 - active/);
 
         // Git commit message
         const logMsg = git('log -1 --pretty=%s', repoDir);
-        expect(logMsg).to.match(/^Switch to nightly \d+\.\d+\.0-next versions$/);
+        expect(logMsg).toMatch(/^Switch to nightly \d+\.\d+\.0-next versions$/);
     });
 });
 
@@ -429,24 +429,24 @@ describe.skipIf(!isMavenAvailable())('releng prepare — glsp-server', function
         const result = runCli(['releng', 'prepare', 'custom', '99.0.0', '--no-push', '--no-check', '-r', repoDir], {
             timeout: 0
         });
-        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).to.equal(0);
+        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).toBe(0);
 
         // Release branch created
         const branches = git('branch', repoDir);
-        expect(branches).to.contain('release-v99.0.0');
+        expect(branches).toContain('release-v99.0.0');
 
         // Version bumped in pom.xml
         const pom = readText(path.join(repoDir, 'pom.xml'));
-        expect(pom).to.contain('<version>99.0.0</version>');
+        expect(pom).toContain('<version>99.0.0</version>');
 
         // CHANGELOG.md updated
         const changelog = readText(path.join(repoDir, 'CHANGELOG.md'));
-        expect(changelog).to.not.contain('## v99.0.0 - active');
-        expect(changelog).to.contain('## [v99.0.0 -');
+        expect(changelog).not.toContain('## v99.0.0 - active');
+        expect(changelog).toContain('## [v99.0.0 -');
 
         // Git commit created
         const logMsg = git('log -1 --pretty=%s', repoDir);
-        expect(logMsg).to.equal('v99.0.0');
+        expect(logMsg).toBe('v99.0.0');
     });
 });
 
@@ -480,26 +480,26 @@ describe.skipIf(!isMavenAvailable())('releng prepare — glsp-eclipse-integratio
         const result = runCli(['releng', 'prepare', 'next', '--no-push', '--no-check', '-r', repoDir], {
             timeout: 0
         });
-        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).to.equal(0);
+        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).toBe(0);
 
         // Nightly branch created
         const branches = git('branch', repoDir);
-        expect(branches).to.match(/nightly-\d+\.\d+\.0-next/);
+        expect(branches).toMatch(/nightly-\d+\.\d+\.0-next/);
 
         // Client npm packages get the -next suffix
         const clientPkg = readJson(path.join(repoDir, 'client', 'package.json'));
-        expect(clientPkg.version as string).to.match(/-next$/);
+        expect(clientPkg.version as string).toMatch(/-next$/);
 
         // Server pom.xml gets a SNAPSHOT version
         const serverPom = readText(path.join(repoDir, 'server', 'pom.xml'));
-        expect(serverPom).to.match(/<version>\d+\.\d+\.0-SNAPSHOT<\/version>/);
+        expect(serverPom).toMatch(/<version>\d+\.\d+\.0-SNAPSHOT<\/version>/);
 
         // CHANGELOG.md has a new active section added
         const changelog = readText(path.join(repoDir, 'CHANGELOG.md'));
-        expect(changelog).to.match(/## v\d+\.\d+\.0 - active/);
+        expect(changelog).toMatch(/## v\d+\.\d+\.0 - active/);
 
         // Git commit message for nightly
         const logMsg = git('log -1 --pretty=%s', repoDir);
-        expect(logMsg).to.match(/^Switch to nightly \d+\.\d+\.0-next versions$/);
+        expect(logMsg).toMatch(/^Switch to nightly \d+\.\d+\.0-next versions$/);
     });
 });
diff --git a/dev-packages/cli/tests/e2e/releng/version.e2e.spec.ts b/dev-packages/cli/tests/e2e/releng/version.e2e.spec.ts
index f61092c..e566b19 100644
--- a/dev-packages/cli/tests/e2e/releng/version.e2e.spec.ts
+++ b/dev-packages/cli/tests/e2e/releng/version.e2e.spec.ts
@@ -71,31 +71,31 @@ for (const repo of NPM_REPOS) {
 
         it(`should set custom version 99.0.0`, function () {
             const result = runCli(['releng', 'version', 'custom', '99.0.0', '-r', repoDir], { timeout: 0 });
-            expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).to.equal(0);
+            expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).toBe(0);
 
             // Root package.json
             const rootPkg = readJson(path.join(repoDir, 'package.json'));
-            expect(rootPkg.version).to.equal('99.0.0');
+            expect(rootPkg.version).toBe('99.0.0');
 
             // At least one workspace package.json updated
             const workspacePkgs = findWorkspacePackageJsons(repoDir);
-            expect(workspacePkgs.length).to.be.greaterThan(0);
+            expect(workspacePkgs.length).toBeGreaterThan(0);
             const firstPkg = readJson(workspacePkgs[0]);
-            expect(firstPkg.version).to.equal('99.0.0');
+            expect(firstPkg.version).toBe('99.0.0');
         });
 
         it(`should set next version`, function () {
             const result = runCli(['releng', 'version', 'next', '-r', repoDir], { timeout: 0 });
-            expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).to.equal(0);
+            expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).toBe(0);
 
             const rootPkg = readJson(path.join(repoDir, 'package.json'));
-            expect(rootPkg.version as string).to.match(/-next$/);
+            expect(rootPkg.version as string).toMatch(/-next$/);
 
             // At least one workspace package.json updated
             const workspacePkgs = findWorkspacePackageJsons(repoDir);
-            expect(workspacePkgs.length).to.be.greaterThan(0);
+            expect(workspacePkgs.length).toBeGreaterThan(0);
             const firstPkg = readJson(workspacePkgs[0]);
-            expect(firstPkg.version as string).to.match(/-next$/);
+            expect(firstPkg.version as string).toMatch(/-next$/);
         });
     });
 }
@@ -122,27 +122,27 @@ describe('releng version — glsp-client (extended)', function () {
         const origVersion = origPkg.version as string;
 
         const result = runCli(['releng', 'version', 'minor', '-r', repoDir], { timeout: 0 });
-        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).to.equal(0);
+        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).toBe(0);
 
         const updatedPkg = readJson(path.join(repoDir, 'package.json'));
         const newVersion = updatedPkg.version as string;
-        expect(newVersion).to.not.equal(origVersion);
+        expect(newVersion).not.toBe(origVersion);
 
         // New version should be a clean semver without pre-release suffix
         // and its minor component should be >= the original base minor
         const origMinor = parseInt(origVersion.replace(/-.*$/, '').split('.')[1], 10);
         const newMinor = parseInt(newVersion.split('.')[1], 10);
-        expect(newMinor).to.be.greaterThanOrEqual(origMinor);
-        expect(newVersion).to.not.contain('-');
+        expect(newMinor).toBeGreaterThanOrEqual(origMinor);
+        expect(newVersion).not.toContain('-');
     });
 
     it('should accept --verbose flag', function () {
         const result = runCli(['releng', 'version', 'custom', '99.0.0', '--verbose', '-r', repoDir], { timeout: 0 });
-        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).to.equal(0);
+        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).toBe(0);
 
         // Verbose mode produces debug output
         const combined = result.stdout + result.stderr;
-        expect(combined).to.contain('Bump version');
+        expect(combined).toContain('Bump version');
     });
 });
 
@@ -165,31 +165,31 @@ describe('releng version — glsp-theia-integration', function () {
 
     it('should set custom version 99.0.0 and update Theia README', function () {
         const result = runCli(['releng', 'version', 'custom', '99.0.0', '-r', repoDir], { timeout: 0 });
-        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).to.equal(0);
+        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).toBe(0);
 
         // NPM checks
         const rootPkg = readJson(path.join(repoDir, 'package.json'));
-        expect(rootPkg.version).to.equal('99.0.0');
+        expect(rootPkg.version).toBe('99.0.0');
 
         const workspacePkgs = findWorkspacePackageJsons(repoDir);
-        expect(workspacePkgs.length).to.be.greaterThan(0);
+        expect(workspacePkgs.length).toBeGreaterThan(0);
 
         // Theia README compatibility table should contain the new version
         const readme = readText(path.join(repoDir, 'README.md'));
-        expect(readme).to.contain('99.0.0');
+        expect(readme).toContain('99.0.0');
     });
 
     it('should set next version', function () {
         const result = runCli(['releng', 'version', 'next', '-r', repoDir], { timeout: 0 });
-        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).to.equal(0);
+        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).toBe(0);
 
         const rootPkg = readJson(path.join(repoDir, 'package.json'));
-        expect(rootPkg.version as string).to.match(/-next$/);
+        expect(rootPkg.version as string).toMatch(/-next$/);
 
         const workspacePkgs = findWorkspacePackageJsons(repoDir);
-        expect(workspacePkgs.length).to.be.greaterThan(0);
+        expect(workspacePkgs.length).toBeGreaterThan(0);
         const firstPkg = readJson(workspacePkgs[0]);
-        expect(firstPkg.version as string).to.match(/-next$/);
+        expect(firstPkg.version as string).toMatch(/-next$/);
     });
 });
 
@@ -216,18 +216,18 @@ describe.skipIf(!isMavenAvailable())('releng version — glsp-server', function
 
     it('should set custom version 99.0.0 in pom.xml', function () {
         const result = runCli(['releng', 'version', 'custom', '99.0.0', '-r', repoDir], { timeout: 0 });
-        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).to.equal(0);
+        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).toBe(0);
 
         const pom = readText(path.join(repoDir, 'pom.xml'));
-        expect(pom).to.contain('<version>99.0.0</version>');
+        expect(pom).toContain('<version>99.0.0</version>');
     });
 
     it('should set next version as SNAPSHOT in pom.xml', function () {
         const result = runCli(['releng', 'version', 'next', '-r', repoDir], { timeout: 0 });
-        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).to.equal(0);
+        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).toBe(0);
 
         const pom = readText(path.join(repoDir, 'pom.xml'));
-        expect(pom).to.match(/<version>\d+\.\d+\.\d+-SNAPSHOT<\/version>/);
+        expect(pom).toMatch(/<version>\d+\.\d+\.\d+-SNAPSHOT<\/version>/);
     });
 });
 
@@ -254,28 +254,28 @@ describe.skipIf(!isMavenAvailable())('releng version — glsp-eclipse-integratio
 
     it('should set custom version 99.0.0 in client and server', function () {
         const result = runCli(['releng', 'version', 'custom', '99.0.0', '-r', repoDir], { timeout: 0 });
-        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).to.equal(0);
+        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).toBe(0);
 
         // Client npm packages
         const clientPkg = readJson(path.join(repoDir, 'client', 'package.json'));
-        expect(clientPkg.version).to.equal('99.0.0');
+        expect(clientPkg.version).toBe('99.0.0');
 
         // Server pom.xml
         const serverPom = readText(path.join(repoDir, 'server', 'pom.xml'));
-        expect(serverPom).to.contain('<version>99.0.0</version>');
+        expect(serverPom).toContain('<version>99.0.0</version>');
     });
 
     it('should set next version in client and server', function () {
         const result = runCli(['releng', 'version', 'next', '-r', repoDir], { timeout: 0 });
-        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).to.equal(0);
+        expect(result.exitCode, `stdout: ${result.stdout}\nstderr: ${result.stderr}`).toBe(0);
 
         // Client should have -next suffix
         const clientPkg = readJson(path.join(repoDir, 'client', 'package.json'));
-        expect(clientPkg.version as string).to.match(/-next$/);
+        expect(clientPkg.version as string).toMatch(/-next$/);
 
         // Server should have -SNAPSHOT suffix
         const serverPom = readText(path.join(repoDir, 'server', 'pom.xml'));
-        expect(serverPom).to.match(/<version>\d+\.\d+\.\d+-SNAPSHOT<\/version>/);
+        expect(serverPom).toMatch(/<version>\d+\.\d+\.\d+-SNAPSHOT<\/version>/);
     });
 });
 
diff --git a/dev-packages/cli/tests/e2e/repo/repo-core-build.e2e.spec.ts b/dev-packages/cli/tests/e2e/repo/repo-core-build.e2e.spec.ts
index 780ab89..0c5fc76 100644
--- a/dev-packages/cli/tests/e2e/repo/repo-core-build.e2e.spec.ts
+++ b/dev-packages/cli/tests/e2e/repo/repo-core-build.e2e.spec.ts
@@ -39,10 +39,10 @@ describe('repo commands — core (build)', function () {
         workDir = createTempDir();
 
         const cloneResult = runCli(['repo', 'clone', '--preset', 'core', '-d', workDir]);
-        expect(cloneResult.exitCode, `clone failed:\n${cliDiag(cloneResult)}`).to.equal(0);
+        expect(cloneResult.exitCode, `clone failed:\n${cliDiag(cloneResult)}`).toBe(0);
 
         const buildResult = runCli(['repo', 'build', '-d', workDir]);
-        expect(buildResult.exitCode, `build failed:\n${cliDiag(buildResult)}`).to.equal(0);
+        expect(buildResult.exitCode, `build failed:\n${cliDiag(buildResult)}`).toBe(0);
     });
 
     afterAll(function () {
@@ -54,13 +54,13 @@ describe('repo commands — core (build)', function () {
     describe('build', function () {
         it('should have built all core repos', function () {
             for (const repo of CORE_REPOS) {
-                expect(fs.existsSync(path.join(workDir, repo, 'node_modules')), `${repo}/node_modules should exist`).to.be.true;
+                expect(fs.existsSync(path.join(workDir, repo, 'node_modules')), `${repo}/node_modules should exist`).toBe(true);
             }
         });
 
         it('should build with --repo filter', function () {
             const result = runCli(['repo', 'build', '-d', workDir, '-r', 'glsp-client']);
-            expect(result.exitCode, cliDiag(result)).to.equal(0);
+            expect(result.exitCode, cliDiag(result)).toBe(0);
         });
 
         it('should continue on failure with --no-fail-fast', function () {
@@ -75,7 +75,7 @@ describe('repo commands — core (build)', function () {
                 );
 
                 const result = runCli(['repo', 'build', '-d', badDir, '--no-fail-fast']);
-                expect(result.exitCode).to.not.equal(0);
+                expect(result.exitCode).not.toBe(0);
             } finally {
                 cleanupTempDir(badDir);
             }
@@ -87,12 +87,12 @@ describe('repo commands — core (build)', function () {
     describe('run', function () {
         it('should run a package script in a repo via scoped command', function () {
             const result = runCli(['repo', 'glsp-client', 'run', '--version', '-d', workDir]);
-            expect(result.exitCode, cliDiag(result)).to.equal(0);
+            expect(result.exitCode, cliDiag(result)).toBe(0);
         });
 
         it('should fail when script does not exist', function () {
             const result = runCli(['repo', 'glsp-client', 'run', 'nonexistent-script-xyz', '-d', workDir]);
-            expect(result.exitCode).to.not.equal(0);
+            expect(result.exitCode).not.toBe(0);
         });
     });
 
@@ -108,8 +108,8 @@ describe('repo commands — core (build)', function () {
             }
 
             const result = runCli(['repo', 'glsp-server-node', 'browser-bundle', '-d', workDir]);
-            expect(result.exitCode, cliDiag(result)).to.equal(0);
-            expect(result.stdout).to.contain('wf-glsp-server-webworker.js');
+            expect(result.exitCode, cliDiag(result)).toBe(0);
+            expect(result.stdout).toContain('wf-glsp-server-webworker.js');
         });
 
         it('should print the node bundle path when bundle exists', function () {
@@ -119,8 +119,8 @@ describe('repo commands — core (build)', function () {
             fs.writeFileSync(bundleFile, 'fake-bundle');
 
             const result = runCli(['repo', 'glsp-server-node', 'node-bundle', '-d', workDir]);
-            expect(result.exitCode, cliDiag(result)).to.equal(0);
-            expect(result.stdout).to.contain('wf-glsp-server-node.js');
+            expect(result.exitCode, cliDiag(result)).toBe(0);
+            expect(result.stdout).toContain('wf-glsp-server-node.js');
         });
 
         it('should fail with helpful message when browser bundle is missing', function () {
@@ -128,9 +128,9 @@ describe('repo commands — core (build)', function () {
             try {
                 fs.mkdirSync(path.join(missingDir, 'glsp-server-node'), { recursive: true });
                 const result = runCli(['repo', 'glsp-server-node', 'browser-bundle', '-d', missingDir]);
-                expect(result.exitCode).to.not.equal(0);
+                expect(result.exitCode).not.toBe(0);
                 const output = result.stdout + result.stderr;
-                expect(output).to.contain('not found');
+                expect(output).toContain('not found');
             } finally {
                 cleanupTempDir(missingDir);
             }
@@ -141,9 +141,9 @@ describe('repo commands — core (build)', function () {
             try {
                 fs.mkdirSync(path.join(missingDir, 'glsp-server-node'), { recursive: true });
                 const result = runCli(['repo', 'glsp-server-node', 'node-bundle', '-d', missingDir]);
-                expect(result.exitCode).to.not.equal(0);
+                expect(result.exitCode).not.toBe(0);
                 const output = result.stdout + result.stderr;
-                expect(output).to.contain('not found');
+                expect(output).toContain('not found');
             } finally {
                 cleanupTempDir(missingDir);
             }
@@ -155,22 +155,22 @@ describe('repo commands — core (build)', function () {
     describe('link', function () {
         it('should link core repos via pnpm-workspace.yaml overrides', function () {
             const result = runCli(['repo', 'link', '-d', workDir]);
-            expect(result.exitCode, cliDiag(result)).to.equal(0);
+            expect(result.exitCode, cliDiag(result)).toBe(0);
 
             // glsp-server-node should consume glsp-client's packages/singletons through link: overrides.
             const serverDir = path.join(workDir, 'glsp-server-node');
             const links = Object.entries(readOverrides(serverDir)).filter(([, value]) => value.startsWith('link:'));
-            expect(links.length, 'expected link: overrides in glsp-server-node').to.be.greaterThan(0);
+            expect(links.length, 'expected link: overrides in glsp-server-node').toBeGreaterThan(0);
             expect(
                 links.some(([, value]) => value.includes('glsp-client')),
                 'expected at least one override pointing into glsp-client'
-            ).to.be.true;
+            ).toBe(true);
 
             // A consumed override should resolve to the local glsp-client checkout.
             const consumed = links.find(([name]) => fs.existsSync(path.join(serverDir, 'node_modules', name)));
             if (consumed) {
                 const real = fs.realpathSync(path.join(serverDir, 'node_modules', consumed[0]));
-                expect(real.startsWith(fs.realpathSync(path.join(workDir, 'glsp-client')))).to.be.true;
+                expect(real.startsWith(fs.realpathSync(path.join(workDir, 'glsp-client')))).toBe(true);
             }
         });
     });
@@ -178,10 +178,10 @@ describe('repo commands — core (build)', function () {
     describe('unlink', function () {
         it('should unlink core repos', function () {
             const result = runCli(['repo', 'unlink', '-d', workDir]);
-            expect(result.exitCode, cliDiag(result)).to.equal(0);
+            expect(result.exitCode, cliDiag(result)).toBe(0);
 
             const links = Object.values(readOverrides(path.join(workDir, 'glsp-server-node'))).filter(value => value.startsWith('link:'));
-            expect(links.length, 'link overrides should be removed after unlink').to.equal(0);
+            expect(links.length, 'link overrides should be removed after unlink').toBe(0);
         });
     });
 
@@ -190,26 +190,26 @@ describe('repo commands — core (build)', function () {
     describe('workspace', function () {
         it('should generate a .code-workspace file', function () {
             const result = runCli(['repo', 'workspace', 'init', '-d', workDir]);
-            expect(result.exitCode, cliDiag(result)).to.equal(0);
+            expect(result.exitCode, cliDiag(result)).toBe(0);
 
             const wsFile = path.join(workDir, 'glsp.code-workspace');
-            expect(fs.existsSync(wsFile)).to.be.true;
+            expect(fs.existsSync(wsFile)).toBe(true);
 
             const ws = readJson(wsFile);
             const folders = ws.folders as { name: string; path: string }[];
-            expect(folders).to.have.length(2);
-            expect(folders.map(f => f.name)).to.include.members(['glsp-client', 'glsp-server-node']);
+            expect(folders).toHaveLength(2);
+            expect(folders.map(f => f.name)).toEqual(expect.arrayContaining(['glsp-client', 'glsp-server-node']));
         });
 
         it('should generate workspace with custom --output path', function () {
             const customPath = path.join(workDir, 'custom', 'my.code-workspace');
             const result = runCli(['repo', 'workspace', 'init', '-d', workDir, '-o', customPath]);
-            expect(result.exitCode, cliDiag(result)).to.equal(0);
-            expect(fs.existsSync(customPath)).to.be.true;
+            expect(result.exitCode, cliDiag(result)).toBe(0);
+            expect(fs.existsSync(customPath)).toBe(true);
 
             const ws = readJson(customPath);
             const folders = ws.folders as { name: string; path: string }[];
-            expect(folders).to.have.length(2);
+            expect(folders).toHaveLength(2);
         });
     });
 });
diff --git a/dev-packages/cli/tests/e2e/repo/repo-core-clone.e2e.spec.ts b/dev-packages/cli/tests/e2e/repo/repo-core-clone.e2e.spec.ts
index 2f592f7..eb41e23 100644
--- a/dev-packages/cli/tests/e2e/repo/repo-core-clone.e2e.spec.ts
+++ b/dev-packages/cli/tests/e2e/repo/repo-core-clone.e2e.spec.ts
@@ -28,7 +28,7 @@ describe('repo commands — core (clone)', function () {
     beforeAll(function () {
         workDir = createTempDir();
         const result = runCli(['repo', 'clone', '--preset', 'core', '-d', workDir]);
-        expect(result.exitCode, cliDiag(result)).to.equal(0);
+        expect(result.exitCode, cliDiag(result)).toBe(0);
     });
 
     afterAll(function () {
@@ -41,9 +41,9 @@ describe('repo commands — core (clone)', function () {
         it('should clone all core repos via --preset', function () {
             for (const repo of CORE_REPOS) {
                 const repoDir = path.join(workDir, repo);
-                expect(fs.existsSync(repoDir), `${repo} should exist`).to.be.true;
-                expect(fs.existsSync(path.join(repoDir, 'package.json')), `${repo}/package.json should exist`).to.be.true;
-                expect(fs.existsSync(path.join(repoDir, '.git')), `${repo}/.git should exist`).to.be.true;
+                expect(fs.existsSync(repoDir), `${repo} should exist`).toBe(true);
+                expect(fs.existsSync(path.join(repoDir, 'package.json')), `${repo}/package.json should exist`).toBe(true);
+                expect(fs.existsSync(path.join(repoDir, '.git')), `${repo}/.git should exist`).toBe(true);
             }
         });
 
@@ -51,8 +51,8 @@ describe('repo commands — core (clone)', function () {
             const singleDir = createTempDir();
             try {
                 const result = runCli(['repo', 'glsp-client', 'clone', '-d', singleDir]);
-                expect(result.exitCode, cliDiag(result)).to.equal(0);
-                expect(fs.existsSync(path.join(singleDir, 'glsp-client', 'package.json'))).to.be.true;
+                expect(result.exitCode, cliDiag(result)).toBe(0);
+                expect(fs.existsSync(path.join(singleDir, 'glsp-client', 'package.json'))).toBe(true);
             } finally {
                 cleanupTempDir(singleDir);
             }
@@ -62,12 +62,12 @@ describe('repo commands — core (clone)', function () {
             const singleDir = createTempDir();
             try {
                 const result = runCli(['repo', 'glsp-client', 'clone', '-d', singleDir, '-p', 'ssh']);
-                expect(result.exitCode, cliDiag(result)).to.equal(0);
+                expect(result.exitCode, cliDiag(result)).toBe(0);
 
                 const repoDir = path.join(singleDir, 'glsp-client');
-                expect(fs.existsSync(repoDir)).to.be.true;
+                expect(fs.existsSync(repoDir)).toBe(true);
                 const remoteUrl = git('remote get-url origin', repoDir);
-                expect(remoteUrl).to.contain('git@github.com:');
+                expect(remoteUrl).toContain('git@github.com:');
             } finally {
                 cleanupTempDir(singleDir);
             }
@@ -77,10 +77,10 @@ describe('repo commands — core (clone)', function () {
             const singleDir = createTempDir();
             try {
                 const result = runCli(['repo', 'glsp-client', 'clone', '-d', singleDir, '-b', 'master']);
-                expect(result.exitCode, cliDiag(result)).to.equal(0);
+                expect(result.exitCode, cliDiag(result)).toBe(0);
 
                 const repoDir = path.join(singleDir, 'glsp-client');
-                expect(currentBranch(repoDir)).to.equal('master');
+                expect(currentBranch(repoDir)).toBe('master');
             } finally {
                 cleanupTempDir(singleDir);
             }
@@ -90,10 +90,10 @@ describe('repo commands — core (clone)', function () {
             const filterDir = createTempDir();
             try {
                 const result = runCli(['repo', 'clone', 'glsp-client', '-d', filterDir]);
-                expect(result.exitCode, cliDiag(result)).to.equal(0);
+                expect(result.exitCode, cliDiag(result)).toBe(0);
 
-                expect(fs.existsSync(path.join(filterDir, 'glsp-client'))).to.be.true;
-                expect(fs.existsSync(path.join(filterDir, 'glsp-server-node'))).to.be.false;
+                expect(fs.existsSync(path.join(filterDir, 'glsp-client'))).toBe(true);
+                expect(fs.existsSync(path.join(filterDir, 'glsp-server-node'))).toBe(false);
             } finally {
                 cleanupTempDir(filterDir);
             }
@@ -107,12 +107,12 @@ describe('repo commands — core (clone)', function () {
                 fs.writeFileSync(marker, 'original');
 
                 const result = runCli(['repo', 'glsp-client', 'clone', '-d', overrideDir, '--override', 'rename']);
-                expect(result.exitCode, cliDiag(result)).to.equal(0);
+                expect(result.exitCode, cliDiag(result)).toBe(0);
 
                 const entries = fs.readdirSync(overrideDir).filter(e => e.startsWith('glsp-client_'));
-                expect(entries).to.have.lengthOf(1);
-                expect(fs.readFileSync(path.join(overrideDir, entries[0], 'test-marker.txt'), 'utf-8')).to.equal('original');
-                expect(fs.existsSync(path.join(overrideDir, 'glsp-client', 'package.json'))).to.be.true;
+                expect(entries).toHaveLength(1);
+                expect(fs.readFileSync(path.join(overrideDir, entries[0], 'test-marker.txt'), 'utf-8')).toBe('original');
+                expect(fs.existsSync(path.join(overrideDir, 'glsp-client', 'package.json'))).toBe(true);
             } finally {
                 cleanupTempDir(overrideDir);
             }
@@ -126,10 +126,10 @@ describe('repo commands — core (clone)', function () {
                 fs.writeFileSync(marker, 'original');
 
                 const result = runCli(['repo', 'glsp-client', 'clone', '-d', overrideDir, '--override', 'remove']);
-                expect(result.exitCode, cliDiag(result)).to.equal(0);
+                expect(result.exitCode, cliDiag(result)).toBe(0);
 
-                expect(fs.existsSync(path.join(overrideDir, 'glsp-client', 'test-marker.txt'))).to.be.false;
-                expect(fs.existsSync(path.join(overrideDir, 'glsp-client', 'package.json'))).to.be.true;
+                expect(fs.existsSync(path.join(overrideDir, 'glsp-client', 'test-marker.txt'))).toBe(false);
+                expect(fs.existsSync(path.join(overrideDir, 'glsp-client', 'package.json'))).toBe(true);
             } finally {
                 cleanupTempDir(overrideDir);
             }
@@ -158,8 +158,8 @@ describe('repo commands — core (clone)', function () {
             git('checkout ' + origBranch, repoDir);
 
             const result = runCli(['repo', 'glsp-client', 'switch', '-b', 'test-switch-branch', '-d', workDir]);
-            expect(result.exitCode, cliDiag(result)).to.equal(0);
-            expect(currentBranch(repoDir)).to.equal('test-switch-branch');
+            expect(result.exitCode, cliDiag(result)).toBe(0);
+            expect(currentBranch(repoDir)).toBe('test-switch-branch');
 
             git('checkout ' + origBranch, repoDir);
             git('branch -d test-switch-branch', repoDir);
@@ -167,10 +167,10 @@ describe('repo commands — core (clone)', function () {
 
         it('should warn when branch does not exist', function () {
             const result = runCli(['repo', 'glsp-client', 'switch', '-b', 'nonexistent-branch-12345', '-d', workDir]);
-            expect(result.exitCode, cliDiag(result)).to.equal(0);
+            expect(result.exitCode, cliDiag(result)).toBe(0);
 
             const combined = result.stdout + result.stderr;
-            expect(combined).to.contain('not found');
+            expect(combined).toContain('not found');
         });
 
         it('should fail without --force when repo has changes', function () {
@@ -179,7 +179,7 @@ describe('repo commands — core (clone)', function () {
             git('add dirty-marker.txt', repoDir);
 
             const result = runCli(['repo', 'glsp-client', 'switch', '-b', 'master', '-d', workDir]);
-            expect(result.exitCode).to.not.equal(0);
+            expect(result.exitCode).not.toBe(0);
 
             resetRepo(repoDir);
         });
@@ -193,8 +193,8 @@ describe('repo commands — core (clone)', function () {
             git('add dirty-marker.txt', repoDir);
 
             const result = runCli(['repo', 'glsp-client', 'switch', '-b', 'test-force-branch', '--force', '-d', workDir]);
-            expect(result.exitCode, cliDiag(result)).to.equal(0);
-            expect(currentBranch(repoDir)).to.equal('test-force-branch');
+            expect(result.exitCode, cliDiag(result)).toBe(0);
+            expect(currentBranch(repoDir)).toBe('test-force-branch');
 
             git('checkout ' + origBranch, repoDir);
             git('branch -D test-force-branch', repoDir);
@@ -206,26 +206,26 @@ describe('repo commands — core (clone)', function () {
     describe('pwd', function () {
         it('should print resolved paths for all repos', function () {
             const result = runCli(['repo', 'pwd', '-d', workDir]);
-            expect(result.exitCode, cliDiag(result)).to.equal(0);
+            expect(result.exitCode, cliDiag(result)).toBe(0);
             for (const repo of CORE_REPOS) {
-                expect(result.stdout).to.contain(repo);
+                expect(result.stdout).toContain(repo);
             }
         });
 
         it('should print raw tab-separated output', function () {
             const result = runCli(['repo', 'pwd', '-d', workDir, '--raw']);
-            expect(result.exitCode, cliDiag(result)).to.equal(0);
+            expect(result.exitCode, cliDiag(result)).toBe(0);
             const lines = result.stdout.trim().split('\n');
-            expect(lines).to.have.lengthOf(2);
+            expect(lines).toHaveLength(2);
             for (const line of lines) {
-                expect(line).to.match(/^glsp-\S+\t\//);
+                expect(line).toMatch(/^glsp-\S+\t\//);
             }
         });
 
         it('should print path for a single repo via scoped command', function () {
             const result = runCli(['repo', 'glsp-client', 'pwd', '-d', workDir]);
-            expect(result.exitCode, cliDiag(result)).to.equal(0);
-            expect(result.stdout.trim()).to.equal(path.resolve(workDir, 'glsp-client'));
+            expect(result.exitCode, cliDiag(result)).toBe(0);
+            expect(result.stdout.trim()).toBe(path.resolve(workDir, 'glsp-client'));
         });
     });
 
@@ -234,15 +234,15 @@ describe('repo commands — core (clone)', function () {
     describe('log', function () {
         it('should print the last commit for all repos', function () {
             const result = runCli(['repo', 'log', '-d', workDir]);
-            expect(result.exitCode, cliDiag(result)).to.equal(0);
-            expect(result.stdout).to.contain('commit');
-            expect(result.stdout).to.contain('Author:');
+            expect(result.exitCode, cliDiag(result)).toBe(0);
+            expect(result.stdout).toContain('commit');
+            expect(result.stdout).toContain('Author:');
         });
 
         it('should print the last commit for a single repo via scoped command', function () {
             const result = runCli(['repo', 'glsp-client', 'log', '-d', workDir]);
-            expect(result.exitCode, cliDiag(result)).to.equal(0);
-            expect(result.stdout).to.contain('commit');
+            expect(result.exitCode, cliDiag(result)).toBe(0);
+            expect(result.stdout).toContain('commit');
         });
     });
 });
diff --git a/dev-packages/cli/tests/e2e/repo/repo-eclipse.e2e.spec.ts b/dev-packages/cli/tests/e2e/repo/repo-eclipse.e2e.spec.ts
index 51b65c5..8de5acf 100644
--- a/dev-packages/cli/tests/e2e/repo/repo-eclipse.e2e.spec.ts
+++ b/dev-packages/cli/tests/e2e/repo/repo-eclipse.e2e.spec.ts
@@ -28,7 +28,7 @@ describe.skipIf(!isMavenAvailable())('repo commands — eclipse', function () {
         workDir = createTempDir();
 
         const cloneResult = runCli(['repo', 'clone', '--preset', 'eclipse', '-d', workDir]);
-        expect(cloneResult.exitCode, `clone failed:\n${cliDiag(cloneResult)}`).to.equal(0);
+        expect(cloneResult.exitCode, `clone failed:\n${cliDiag(cloneResult)}`).toBe(0);
 
         // Build with --no-fail-fast so all repos are attempted even if one fails.
         // The Tycho build for glsp-eclipse-integration/server depends on Eclipse p2
@@ -44,16 +44,16 @@ describe.skipIf(!isMavenAvailable())('repo commands — eclipse', function () {
 
     it('should have built glsp-server with Maven', function () {
         const targetDir = path.join(workDir, 'glsp-server', 'examples', 'org.eclipse.glsp.example.workflow', 'target');
-        expect(fs.existsSync(targetDir), 'Maven target directory should exist').to.be.true;
+        expect(fs.existsSync(targetDir), 'Maven target directory should exist').toBe(true);
     });
 
     it('should build glsp-server via scoped command', function () {
         const result = runCli(['repo', 'glsp-server', 'build', '-d', workDir]);
-        expect(result.exitCode, cliDiag(result)).to.equal(0);
+        expect(result.exitCode, cliDiag(result)).toBe(0);
     });
 
     it('should build glsp-eclipse-integration via scoped command', function () {
         const result = runCli(['repo', 'glsp-eclipse-integration', 'build', '-d', workDir]);
-        expect(result.exitCode, cliDiag(result)).to.equal(0);
+        expect(result.exitCode, cliDiag(result)).toBe(0);
     });
 });
diff --git a/dev-packages/cli/tests/e2e/repo/repo-theia.e2e.spec.ts b/dev-packages/cli/tests/e2e/repo/repo-theia.e2e.spec.ts
index 96a2b0f..87ea9da 100644
--- a/dev-packages/cli/tests/e2e/repo/repo-theia.e2e.spec.ts
+++ b/dev-packages/cli/tests/e2e/repo/repo-theia.e2e.spec.ts
@@ -25,10 +25,10 @@ describe('repo commands — theia', function () {
         workDir = createTempDir();
 
         const cloneResult = runCli(['repo', 'clone', '--preset', 'theia', '-d', workDir]);
-        expect(cloneResult.exitCode, `clone failed:\n${cliDiag(cloneResult)}`).to.equal(0);
+        expect(cloneResult.exitCode, `clone failed:\n${cliDiag(cloneResult)}`).toBe(0);
 
         const buildResult = runCli(['repo', 'build', '-d', workDir]);
-        expect(buildResult.exitCode, `build failed:\n${cliDiag(buildResult)}`).to.equal(0);
+        expect(buildResult.exitCode, `build failed:\n${cliDiag(buildResult)}`).toBe(0);
     });
 
     afterAll(function () {
@@ -37,6 +37,6 @@ describe('repo commands — theia', function () {
 
     it('should build theia-integration with scoped build', function () {
         const result = runCli(['repo', 'glsp-theia-integration', 'build', '-d', workDir]);
-        expect(result.exitCode, cliDiag(result)).to.equal(0);
+        expect(result.exitCode, cliDiag(result)).toBe(0);
     });
 });
diff --git a/dev-packages/cli/tests/e2e/repo/repo-vscode.e2e.spec.ts b/dev-packages/cli/tests/e2e/repo/repo-vscode.e2e.spec.ts
index bbc0e5a..ec5ba21 100644
--- a/dev-packages/cli/tests/e2e/repo/repo-vscode.e2e.spec.ts
+++ b/dev-packages/cli/tests/e2e/repo/repo-vscode.e2e.spec.ts
@@ -27,10 +27,10 @@ describe('repo commands — vscode', function () {
         workDir = createTempDir();
 
         const cloneResult = runCli(['repo', 'clone', '--preset', 'vscode', '-d', workDir]);
-        expect(cloneResult.exitCode, `clone failed:\n${cliDiag(cloneResult)}`).to.equal(0);
+        expect(cloneResult.exitCode, `clone failed:\n${cliDiag(cloneResult)}`).toBe(0);
 
         const buildResult = runCli(['repo', 'build', '-d', workDir]);
-        expect(buildResult.exitCode, `build failed:\n${cliDiag(buildResult)}`).to.equal(0);
+        expect(buildResult.exitCode, `build failed:\n${cliDiag(buildResult)}`).toBe(0);
     });
 
     afterAll(function () {
@@ -39,54 +39,54 @@ describe('repo commands — vscode', function () {
 
     it('should build vscode-integration with scoped build', function () {
         const result = runCli(['repo', 'glsp-vscode-integration', 'build', '-d', workDir]);
-        expect(result.exitCode, cliDiag(result)).to.equal(0);
+        expect(result.exitCode, cliDiag(result)).toBe(0);
     });
 
     // ── Package ───────────────────────────────────────────────────────────
 
     it('should package the VS Code extension as VSIX', function () {
         const result = runCli(['repo', 'glsp-vscode-integration', 'package', '-d', workDir]);
-        expect(result.exitCode, cliDiag(result)).to.equal(0);
+        expect(result.exitCode, cliDiag(result)).toBe(0);
 
         const vsixDir = path.join(workDir, 'glsp-vscode-integration', 'example', 'workflow', 'extension');
         const vsixFiles = fs.readdirSync(vsixDir).filter(f => f.endsWith('.vsix'));
-        expect(vsixFiles).to.have.lengthOf.at.least(1);
+        expect(vsixFiles.length).toBeGreaterThanOrEqual(1);
     });
 
     it('should package the VS Code web extension as VSIX', function () {
         const result = runCli(['repo', 'glsp-vscode-integration', 'web-package', '-d', workDir]);
-        expect(result.exitCode, cliDiag(result)).to.equal(0);
+        expect(result.exitCode, cliDiag(result)).toBe(0);
 
         const vsixDir = path.join(workDir, 'glsp-vscode-integration', 'example', 'workflow', 'web-extension');
         const vsixFiles = fs.readdirSync(vsixDir).filter(f => f.endsWith('.vsix'));
-        expect(vsixFiles).to.have.lengthOf.at.least(1);
+        expect(vsixFiles.length).toBeGreaterThanOrEqual(1);
     });
 
     // ── VSIX path ─────────────────────────────────────────────────────────
 
     it('should print the VSIX path after packaging', function () {
         const result = runCli(['repo', 'glsp-vscode-integration', 'vsix-path', '-d', workDir]);
-        expect(result.exitCode, cliDiag(result)).to.equal(0);
-        expect(result.stdout).to.match(/\.vsix$/);
+        expect(result.exitCode, cliDiag(result)).toBe(0);
+        expect(result.stdout).toMatch(/\.vsix$/);
     });
 
     it('should print the web extension VSIX path after packaging', function () {
         const result = runCli(['repo', 'glsp-vscode-integration', 'web-vsix-path', '-d', workDir]);
-        expect(result.exitCode, cliDiag(result)).to.equal(0);
-        expect(result.stdout).to.match(/\.vsix$/);
+        expect(result.exitCode, cliDiag(result)).toBe(0);
+        expect(result.stdout).toMatch(/\.vsix$/);
     });
 
     // ── VSIX ID ───────────────────────────────────────────────────────────
 
     it('should print the VSIX ID', function () {
         const result = runCli(['repo', 'glsp-vscode-integration', 'vsix-id']);
-        expect(result.exitCode, cliDiag(result)).to.equal(0);
-        expect(result.stdout).to.equal('eclipse-glsp.workflow-vscode-example');
+        expect(result.exitCode, cliDiag(result)).toBe(0);
+        expect(result.stdout).toBe('eclipse-glsp.workflow-vscode-example');
     });
 
     it('should print the web extension VSIX ID', function () {
         const result = runCli(['repo', 'glsp-vscode-integration', 'web-vsix-id']);
-        expect(result.exitCode, cliDiag(result)).to.equal(0);
-        expect(result.stdout).to.equal('eclipse-glsp.workflow-vscode-example-web');
+        expect(result.exitCode, cliDiag(result)).toBe(0);
+        expect(result.stdout).toBe('eclipse-glsp.workflow-vscode-example-web');
     });
 });
diff --git a/dev-packages/cli/tests/e2e/update-next.e2e.spec.ts b/dev-packages/cli/tests/e2e/update-next.e2e.spec.ts
index ffeddd9..f914372 100644
--- a/dev-packages/cli/tests/e2e/update-next.e2e.spec.ts
+++ b/dev-packages/cli/tests/e2e/update-next.e2e.spec.ts
@@ -40,12 +40,12 @@ describe('updateNext e2e', () => {
         fs.writeFileSync(pkgPath, JSON.stringify({ name: 'test', version: '1.0.1', private: true, workspaces: [] }, undefined, 2));
         const result = runCli(['updateNext', repoDir]);
         // LOGGER.warn uses console.warn which writes to stderr
-        expect(result.stderr).to.contain('Uncommitted changes');
+        expect(result.stderr).toContain('Uncommitted changes');
     });
 
     it('should error for non-existent directory', () => {
         const result = runCli(['updateNext', '/non/existent/path']);
-        expect(result.exitCode).to.not.equal(0);
+        expect(result.exitCode).not.toBe(0);
     });
 
     it('should show debug output with --verbose', () => {
@@ -56,6 +56,6 @@ describe('updateNext e2e', () => {
         execSync('git add . && git commit -m "add package.json"', { cwd: repoDir });
         const result = runCli(['updateNext', repoDir, '--verbose']);
         const output = result.stdout + result.stderr;
-        expect(output).to.contain('Scanning');
+        expect(output).toContain('Scanning');
     });
 });
diff --git a/dev-packages/config/package.json b/dev-packages/config/package.json
index a562924..0093abc 100644
--- a/dev-packages/config/package.json
+++ b/dev-packages/config/package.json
@@ -33,7 +33,6 @@
     "eslint": "^10.5.0",
     "eslint-config-prettier": "^10.0.0",
     "eslint-import-resolver-typescript": "^4.0.0",
-    "eslint-plugin-chai-friendly": "^1.0.0",
     "eslint-plugin-import-x": "^4.16.2",
     "eslint-plugin-no-null": "^1.0.2",
     "globals": "^17.6.0",
diff --git a/dev-packages/eslint-config/configs/base.js b/dev-packages/eslint-config/configs/base.js
index e8b3315..126a94b 100644
--- a/dev-packages/eslint-config/configs/base.js
+++ b/dev-packages/eslint-config/configs/base.js
@@ -3,7 +3,6 @@ const tseslint = require('typescript-eslint');
 const importX = require('eslint-plugin-import-x');
 const header = require('@tony.ganchev/eslint-plugin-header');
 const noNull = require('eslint-plugin-no-null');
-const chaiFriendly = require('eslint-plugin-chai-friendly');
 const stylistic = require('@stylistic/eslint-plugin');
 const globals = require('globals');
 
@@ -22,14 +21,12 @@ module.exports = [
             },
             globals: {
                 ...globals.browser,
-                ...globals.mocha,
                 ...globals.es2015
             }
         },
         plugins: {
             header: header,
             'no-null': noNull,
-            'chai-friendly': chaiFriendly,
             '@stylistic': stylistic
         }
     }
diff --git a/dev-packages/eslint-config/configs/errors.js b/dev-packages/eslint-config/configs/errors.js
index a612387..1c978a8 100644
--- a/dev-packages/eslint-config/configs/errors.js
+++ b/dev-packages/eslint-config/configs/errors.js
@@ -75,9 +75,7 @@ module.exports = [
             'import-x/export': 'off', // we have multiple exports due to namespaces, enums and classes that share the same name
             // eslint-plugin-no-null
             'no-null/no-null': 'error',
-            // chai friendly
-            'no-unused-expressions': 'off',
-            'chai-friendly/no-unused-expressions': [
+            'no-unused-expressions': [
                 'error',
                 {
                     allowShortCircuit: true,
diff --git a/dev-packages/eslint-config/package.json b/dev-packages/eslint-config/package.json
index 268af70..97eb2f0 100644
--- a/dev-packages/eslint-config/package.json
+++ b/dev-packages/eslint-config/package.json
@@ -38,7 +38,6 @@
     "eslint": "^10.5.0",
     "eslint-config-prettier": "^10.0.0",
     "eslint-import-resolver-typescript": "^4.0.0",
-    "eslint-plugin-chai-friendly": "^1.0.0",
     "eslint-plugin-import-x": "^4.16.2",
     "eslint-plugin-no-null": "^1.0.2",
     "globals": "^17.6.0",
diff --git a/package.json b/package.json
index 77dbd54..6f15b14 100644
--- a/package.json
+++ b/package.json
@@ -19,6 +19,7 @@
     "publish:latest": "glsp releng publish latest",
     "publish:next": "glsp releng publish next",
     "test": "pnpm -C dev-packages/cli test",
+    "test:coverage": "pnpm -C dev-packages/cli test:coverage",
     "test:e2e": "pnpm -C dev-packages/cli test:e2e",
     "watch": "pnpm cli watch"
   },
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 6fadb94..89f9777 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -83,9 +83,6 @@ importers:
       eslint-import-resolver-typescript:
         specifier: ^4.0.0
         version: 4.4.5(eslint-plugin-import-x@4.16.2(@typescript-eslint/utils@8.61.1(eslint@10.5.0)(typescript@5.9.3))(eslint@10.5.0))(eslint@10.5.0)
-      eslint-plugin-chai-friendly:
-        specifier: ^1.0.0
-        version: 1.2.1(eslint@10.5.0)
       eslint-plugin-import-x:
         specifier: ^4.16.2
         version: 4.16.2(@typescript-eslint/utils@8.61.1(eslint@10.5.0)(typescript@5.9.3))(eslint@10.5.0)
@@ -149,9 +146,6 @@ importers:
       eslint-import-resolver-typescript:
         specifier: ^4.0.0
         version: 4.4.5(eslint-plugin-import-x@4.16.2(@typescript-eslint/utils@8.61.1(eslint@10.5.0)(typescript@5.9.3))(eslint@10.5.0))(eslint@10.5.0)
-      eslint-plugin-chai-friendly:
-        specifier: ^1.0.0
-        version: 1.2.1(eslint@10.5.0)
       eslint-plugin-import-x:
         specifier: ^4.16.2
         version: 4.16.2(@typescript-eslint/utils@8.61.1(eslint@10.5.0)(typescript@5.9.3))(eslint@10.5.0)
@@ -955,12 +949,6 @@ packages:
       eslint-plugin-import-x:
         optional: true
 
-  eslint-plugin-chai-friendly@1.2.1:
-    resolution: {integrity: sha512-mV3EOJLDr8+L+LS8uCkP711fnNHz+4PsmPyz18xwkvjJwfLRlnx0Eu6CFnb5B+dW5ahoav2jVer2KFYsmIuv3A==}
-    engines: {node: '>=0.10.0'}
-    peerDependencies:
-      eslint: '>=3.0.0'
-
   eslint-plugin-import-x@4.16.2:
     resolution: {integrity: sha512-rM9K8UBHcWKpzQzStn1YRN2T5NvdeIfSVoKu/lKF41znQXHAUcBbYXe5wd6GNjZjTrP7viQ49n1D83x/2gYgIw==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
@@ -2280,10 +2268,6 @@ snapshots:
     transitivePeerDependencies:
       - supports-color
 
-  eslint-plugin-chai-friendly@1.2.1(eslint@10.5.0):
-    dependencies:
-      eslint: 10.5.0
-
   eslint-plugin-import-x@4.16.2(@typescript-eslint/utils@8.61.1(eslint@10.5.0)(typescript@5.9.3))(eslint@10.5.0):
     dependencies:
       '@package-json/types': 0.0.12