fix: transpile development TypeScript with Oxc

CONTRIBUTING.md

@@ -21,6 +21,10 @@ bun install --frozen-lockfile
 bun run dev
 ```
 
+Development TypeScript runs on Node.js with `@oxc-node/core` for transpilation, including the
+isolated runtime executor. Production continues to run compiled JavaScript. Type checking runs
+separately through `bun run check`.
+
 The development Workbench listens on `http://127.0.0.1:5174` and proxies API requests to the
 Server on `http://127.0.0.1:3001`. The first run writes an operator token to
 `apps/server/.open-flow-dev/operator-token`; later runs reuse it. Set `OPEN_FLOW_TOKEN` to use an

apps/server/node/runtime/isolated-vm.ts

@@ -317,7 +317,8 @@ export class IsolatedVmHost {
   #start(): ChildProcess {
     const modulePath = fileURLToPath(import.meta.url)
     const executorPath = fileURLToPath(new URL(modulePath.endsWith('.ts') ? './isolated-vm-executor.ts' : './isolated-vm-executor.js', import.meta.url))
-    const child = spawn(process.execPath, ['--no-node-snapshot', executorPath, '--executor'], {
+    const loaderArgs = modulePath.endsWith('.ts') ? ['--import', import.meta.resolve('@oxc-node/core/register')] : []
+    const child = spawn(process.execPath, ['--no-node-snapshot', ...loaderArgs, executorPath, '--executor'], {
       env: { NODE_ENV: 'production' },
       stdio: ['ignore', 'ignore', 'pipe', 'ipc'],
     }) as ChildProcessByStdio<null, null, Readable>

apps/server/package.json

@@ -36,6 +36,8 @@
   },
   "devDependencies": {
     "@modelcontextprotocol/client": "2.0.0",
+    "@oomol-lab/open-flow-command": "workspace:*",
+    "@oxc-node/core": "1.0.1",
     "@tailwindcss/vite": "^4",
     "@types/node": "^26.0.0",
     "@types/react": "^18.3.12",
@@ -49,7 +51,6 @@
     "tailwindcss": "^4",
     "typescript": "7.0.2",
     "vite": "8.2.1",
-    "vitest": "^5.0.0",
-    "@oomol-lab/open-flow-command": "workspace:*"
+    "vitest": "^5.0.0"
   }
 }

apps/server/scripts/dev.ts

@@ -64,7 +64,7 @@ export function developmentBackendPlugin(): Plugin {
       }
 
       const developmentToken = configuredOperatorToken == null ? await loadDevelopmentToken() : { created: false, token: configuredOperatorToken }
-      backend = spawn('node', ['--watch', '--no-node-snapshot', 'node/main.ts', '--api-only'], {
+      backend = spawn('node', ['--watch', '--no-node-snapshot', '--import', '@oxc-node/core/register', 'node/main.ts', '--api-only'], {
         cwd: appRoot,
         env: {
           ...process.env,

package.json

@@ -9,6 +9,7 @@
     "apps/*"
   ],
   "devDependencies": {
+    "@oxc-node/core": "1.0.1",
     "oxfmt": "^0.60.0",
     "wrangler": "4.132.0"
   },
@@ -28,7 +29,7 @@
     "test:docker": "bun run --filter @oomol-lab/open-flow-server test:docker",
     "test:npm-package": "bun run --filter @oomol-lab/open-flow test:package",
     "test:package": "bun run test:npm-package",
-    "lab": "node --no-node-snapshot apps/server/scripts/lab/main.ts",
+    "lab": "node --no-node-snapshot --import @oxc-node/core/register apps/server/scripts/lab/main.ts",
     "flow": "bun apps/server/scripts/flow.ts",
     "skill:generate": "bun run --filter @oomol-lab/open-flow skill:generate"
   }