feat: add OpenCode engine integration (re-apply PR #18403)

.github/workflows/smoke-opencode.md

@@ -0,0 +1,80 @@
+---
+description: Smoke test workflow that validates OpenCode engine functionality twice daily
+on:
+  schedule: every 12h
+  workflow_dispatch:
+  pull_request:
+    types: [labeled]
+    names: ["smoke"]
+  reaction: "eyes"
+  status-comment: true
+permissions:
+  contents: read
+  issues: read
+  pull-requests: read
+name: Smoke OpenCode
+engine:
+  id: opencode
+  model: anthropic/claude-sonnet-4-20250514
+strict: true
+imports:
+  - shared/gh.md
+  - shared/reporting.md
+network:
+  allowed:
+    - defaults
+    - github
+tools:
+  cache-memory: true
+  github:
+    toolsets: [repos, pull_requests]
+  edit:
+  bash:
+    - "*"
+  web-fetch:
+safe-outputs:
+    add-comment:
+      hide-older-comments: true
+      max: 2
+    create-issue:
+      expires: 2h
+      close-older-issues: true
+      labels: [automation, testing]
+    add-labels:
+      allowed: [smoke-opencode]
+    messages:
+      footer: "> ⚡ *[{workflow_name}]({run_url}) — Powered by OpenCode*"
+      run-started: "⚡ OpenCode initializing... [{workflow_name}]({run_url}) begins on this {event_type}..."
+      run-success: "🎯 [{workflow_name}]({run_url}) **MISSION COMPLETE!** OpenCode has delivered. ⚡"
+      run-failure: "⚠️ [{workflow_name}]({run_url}) {status}. OpenCode encountered unexpected challenges..."
+timeout-minutes: 15
+---
+
+# Smoke Test: OpenCode Engine Validation
+
+**CRITICAL EFFICIENCY REQUIREMENTS:**
+- Keep ALL outputs extremely short and concise. Use single-line responses.
+- NO verbose explanations or unnecessary context.
+- Minimize file reading - only read what is absolutely necessary for the task.
+
+## Test Requirements
+
+1. **GitHub MCP Testing**: Use GitHub MCP tools to fetch details of exactly 2 merged pull requests from ${{ github.repository }} (title and number only)
+2. **Web Fetch Testing**: Use the web-fetch MCP tool to fetch https://github.com and verify the response contains "GitHub" (do NOT use bash or playwright for this test - use the web-fetch MCP tool directly)
+3. **File Writing Testing**: Create a test file `/tmp/gh-aw/agent/smoke-test-opencode-${{ github.run_id }}.txt` with content "Smoke test passed for OpenCode at $(date)" (create the directory if it doesn't exist)
+4. **Bash Tool Testing**: Execute bash commands to verify file creation was successful (use `cat` to read the file back)
+5. **Build gh-aw**: Run `GOCACHE=/tmp/go-cache GOMODCACHE=/tmp/go-mod make build` to verify the agent can successfully build the gh-aw project. If the command fails, mark this test as ❌ and report the failure.
+
+## Output
+
+Add a **very brief** comment (max 5-10 lines) to the current pull request with:
+- ✅ or ❌ for each test result
+- Overall status: PASS or FAIL
+
+If all tests pass, use the `add_labels` safe-output tool to add the label `smoke-opencode` to the pull request.
+
+**Important**: If no action is needed after completing your analysis, you **MUST** call the `noop` safe-output tool with a brief explanation. Failing to call any safe-output tool is the most common cause of safe-output workflow failures.
+
+```json
+{"noop": {"message": "No action needed: [brief explanation of what was analyzed and why]"}}
+```

actions/setup/sh/convert_gateway_config_opencode.sh

@@ -0,0 +1,114 @@
+#!/usr/bin/env bash
+# Convert MCP Gateway Configuration to OpenCode Format
+# This script converts the gateway's standard HTTP-based MCP configuration
+# to the JSON format expected by OpenCode (opencode.jsonc)
+#
+# OpenCode reads MCP server configuration from opencode.jsonc:
+# - Project: ./opencode.jsonc (used here)
+# - Global: ~/.config/opencode/opencode.json
+#
+# See: https://opencode.ai/docs/mcp-servers/
+
+set -e
+
+# Required environment variables:
+# - MCP_GATEWAY_OUTPUT: Path to gateway output configuration file
+# - MCP_GATEWAY_DOMAIN: Domain to use for MCP server URLs (e.g., host.docker.internal)
+# - MCP_GATEWAY_PORT: Port for MCP gateway (e.g., 80)
+# - GITHUB_WORKSPACE: Workspace directory for project-level config
+
+if [ -z "$MCP_GATEWAY_OUTPUT" ]; then
+  echo "ERROR: MCP_GATEWAY_OUTPUT environment variable is required"
+  exit 1
+fi
+
+if [ ! -f "$MCP_GATEWAY_OUTPUT" ]; then
+  echo "ERROR: Gateway output file not found: $MCP_GATEWAY_OUTPUT"
+  exit 1
+fi
+
+if [ -z "$MCP_GATEWAY_DOMAIN" ]; then
+  echo "ERROR: MCP_GATEWAY_DOMAIN environment variable is required"
+  exit 1
+fi
+
+if [ -z "$MCP_GATEWAY_PORT" ]; then
+  echo "ERROR: MCP_GATEWAY_PORT environment variable is required"
+  exit 1
+fi
+
+if [ -z "$GITHUB_WORKSPACE" ]; then
+  echo "ERROR: GITHUB_WORKSPACE environment variable is required"
+  exit 1
+fi
+
+echo "Converting gateway configuration to OpenCode format..."
+echo "Input: $MCP_GATEWAY_OUTPUT"
+echo "Target domain: $MCP_GATEWAY_DOMAIN:$MCP_GATEWAY_PORT"
+
+# Convert gateway output to OpenCode opencode.jsonc format
+# Gateway format:
+# {
+#   "mcpServers": {
+#     "server-name": {
+#       "type": "http",
+#       "url": "http://domain:port/mcp/server-name",
+#       "headers": {
+#         "Authorization": "apiKey"
+#       }
+#     }
+#   }
+# }
+#
+# OpenCode format:
+# {
+#   "mcp": {
+#     "server-name": {
+#       "type": "remote",
+#       "enabled": true,
+#       "url": "http://domain:port/mcp/server-name",
+#       "headers": {
+#         "Authorization": "apiKey"
+#       }
+#     }
+#   }
+# }
+#
+# The main differences:
+# 1. Top-level key is "mcp" not "mcpServers"
+# 2. Server type is "remote" not "http"
+# 3. Has "enabled": true field
+# 4. Remove "tools" field (Copilot-specific)
+# 5. URLs must use the correct domain (host.docker.internal) for container access
+
+# Build the correct URL prefix using the configured domain and port
+URL_PREFIX="http://${MCP_GATEWAY_DOMAIN}:${MCP_GATEWAY_PORT}"
+
+OPENCODE_CONFIG_FILE="${GITHUB_WORKSPACE}/opencode.jsonc"
+
+# Build the MCP section from gateway output
+MCP_SECTION=$(jq --arg urlPrefix "$URL_PREFIX" '
+  .mcpServers | with_entries(
+    .value |= {
+      "type": "remote",
+      "enabled": true,
+      "url": (.url | sub("^http://[^/]+/mcp/"; $urlPrefix + "/mcp/")),
+      "headers": .headers
+    }
+  )
+' "$MCP_GATEWAY_OUTPUT")
+
+# Merge into existing opencode.jsonc or create new one
+if [ -f "$OPENCODE_CONFIG_FILE" ]; then
+  echo "Merging MCP config into existing opencode.jsonc..."
+  jq --argjson mcpSection "$MCP_SECTION" '.mcp = (.mcp // {}) * $mcpSection' "$OPENCODE_CONFIG_FILE" > "${OPENCODE_CONFIG_FILE}.tmp"
+  mv "${OPENCODE_CONFIG_FILE}.tmp" "$OPENCODE_CONFIG_FILE"
+else
+  echo "Creating new opencode.jsonc..."
+  jq -n --argjson mcpSection "$MCP_SECTION" '{"mcp": $mcpSection}' > "$OPENCODE_CONFIG_FILE"
+fi
+
+echo "OpenCode configuration written to $OPENCODE_CONFIG_FILE"
+echo ""
+echo "Converted configuration:"
+cat "$OPENCODE_CONFIG_FILE"

actions/setup/sh/start_mcp_gateway.sh

@@ -400,6 +400,10 @@ case "$ENGINE_TYPE" in
     echo "Using Gemini converter..."
     bash ${RUNNER_TEMP}/gh-aw/actions/convert_gateway_config_gemini.sh
     ;;
+  opencode)
+    echo "Using OpenCode converter..."
+    bash ${RUNNER_TEMP}/gh-aw/actions/convert_gateway_config_opencode.sh
+    ;;
   *)
     echo "No agent-specific converter found for engine: $ENGINE_TYPE"
     echo "Using gateway output directly"

pkg/constants/constants.go

@@ -100,6 +100,9 @@ const (
 
 	// GeminiLLMGatewayPort is the port for the Gemini LLM gateway
 	GeminiLLMGatewayPort = 10003
+
+	// OpenCodeLLMGatewayPort is the port for the OpenCode LLM gateway
+	OpenCodeLLMGatewayPort = 10004
 )
 
 // DefaultGitHubLockdown is the default value for the GitHub MCP server lockdown setting.

pkg/constants/constants_test.go

@@ -83,7 +83,7 @@ func TestAgenticEngines(t *testing.T) {
 		t.Error("AgenticEngines should not be empty")
 	}
 
-	expectedEngines := []string{"claude", "codex", "copilot", "gemini"}
+	expectedEngines := []string{"claude", "codex", "copilot", "gemini", "opencode"}
 	if len(AgenticEngines) != len(expectedEngines) {
 		t.Errorf("AgenticEngines length = %d, want %d", len(AgenticEngines), len(expectedEngines))
 	}

pkg/constants/engine_constants.go

@@ -20,6 +20,8 @@ const (
 	CodexEngine EngineName = "codex"
 	// GeminiEngine is the Google Gemini engine identifier
 	GeminiEngine EngineName = "gemini"
+	// OpenCodeEngine is the OpenCode engine identifier
+	OpenCodeEngine EngineName = "opencode"
 
 	// DefaultEngine is the default agentic engine used when no engine is explicitly specified.
 	// Currently defaults to CopilotEngine.
@@ -30,7 +32,7 @@ const (
 // Deprecated: Use workflow.NewEngineCatalog(workflow.NewEngineRegistry()).IDs() for a
 // catalog-derived list. This slice is maintained for backward compatibility and must
 // stay in sync with the built-in engines registered in NewEngineCatalog.
-var AgenticEngines = []string{string(ClaudeEngine), string(CodexEngine), string(CopilotEngine), string(GeminiEngine)}
+var AgenticEngines = []string{string(ClaudeEngine), string(CodexEngine), string(CopilotEngine), string(GeminiEngine), string(OpenCodeEngine)}
 
 // EngineOption represents a selectable AI engine with its display metadata and secret configuration
 type EngineOption struct {
@@ -83,6 +85,15 @@ var EngineOptions = []EngineOption{
 		KeyURL:      "https://aistudio.google.com/app/apikey",
 		WhenNeeded:  "Gemini engine workflows",
 	},
+	{
+		Value:              string(OpenCodeEngine),
+		Label:              "OpenCode",
+		Description:        "OpenCode multi-provider AI coding agent (BYOK)",
+		SecretName:         "ANTHROPIC_API_KEY",
+		AlternativeSecrets: []string{"OPENAI_API_KEY", "GOOGLE_API_KEY"},
+		KeyURL:             "https://opencode.ai/docs/get-started/",
+		WhenNeeded:         "OpenCode engine workflows (default: Anthropic provider)",
+	},
 }
 
 // SystemSecretSpec describes a system-level secret that is not engine-specific
@@ -177,6 +188,10 @@ const (
 	EnvVarModelDetectionCodex = "GH_AW_MODEL_DETECTION_CODEX"
 	// EnvVarModelDetectionGemini configures the default Gemini model for detection
 	EnvVarModelDetectionGemini = "GH_AW_MODEL_DETECTION_GEMINI"
+	// EnvVarModelAgentOpenCode configures the default OpenCode model for agent execution
+	EnvVarModelAgentOpenCode = "GH_AW_MODEL_AGENT_OPENCODE"
+	// EnvVarModelDetectionOpenCode configures the default OpenCode model for detection
+	EnvVarModelDetectionOpenCode = "GH_AW_MODEL_DETECTION_OPENCODE"
 
 	// CopilotCLIModelEnvVar is the native environment variable name supported by the Copilot CLI
 	// for selecting the model. Setting this env var is equivalent to passing --model to the CLI.
@@ -198,6 +213,10 @@ const (
 	// for selecting the model. Setting this env var is equivalent to passing --model to the CLI.
 	GeminiCLIModelEnvVar = "GEMINI_MODEL"
 
+	// OpenCodeCLIModelEnvVar is the native environment variable name for OpenCode model selection.
+	// OpenCode uses provider/model format (e.g., "anthropic/claude-sonnet-4-20250514").
+	OpenCodeCLIModelEnvVar = "OPENCODE_MODEL"
+
 	// Common environment variable names used across all engines
 
 	// EnvVarPrompt is the path to the workflow prompt file

pkg/constants/version_constants.go

@@ -47,6 +47,9 @@ const DefaultCodexVersion Version = "0.118.0"
 // DefaultGeminiVersion is the default version of the Google Gemini CLI
 const DefaultGeminiVersion Version = "0.37.1"
 
+// DefaultOpenCodeVersion is the default version of the OpenCode CLI
+const DefaultOpenCodeVersion Version = "1.2.14"
+
 // DefaultGitHubMCPServerVersion is the default version of the GitHub MCP server Docker image
 const DefaultGitHubMCPServerVersion Version = "v0.32.0"
 

pkg/parser/schemas/main_workflow_schema.json

@@ -9116,15 +9116,15 @@
       "oneOf": [
         {
           "type": "string",
-          "description": "Engine name: built-in ('claude', 'codex', 'copilot', 'gemini') or a named catalog entry"
+          "description": "Engine name: built-in ('claude', 'codex', 'copilot', 'gemini', 'opencode') or a named catalog entry"
         },
         {
           "type": "object",
           "description": "Extended engine configuration object with advanced options for model selection, turn limiting, environment variables, and custom steps",
           "properties": {
             "id": {
               "type": "string",
-              "description": "AI engine identifier: built-in ('claude', 'codex', 'copilot', 'gemini') or a named catalog entry"
+              "description": "AI engine identifier: built-in ('claude', 'codex', 'copilot', 'gemini', 'opencode') or a named catalog entry"
             },
             "version": {
               "type": ["string", "number"],
@@ -9285,8 +9285,8 @@
               "properties": {
                 "id": {
                   "type": "string",
-                  "description": "Runtime adapter identifier (e.g. 'codex', 'claude', 'copilot', 'gemini')",
-                  "examples": ["codex", "claude", "copilot", "gemini"]
+                  "description": "Runtime adapter identifier (e.g. 'codex', 'claude', 'copilot', 'gemini', 'opencode')",
+                  "examples": ["codex", "claude", "copilot", "gemini", "opencode"]
                 },
                 "version": {
                   "type": ["string", "number"],

pkg/workflow/agentic_engine.go

@@ -440,6 +440,7 @@ func NewEngineRegistry() *EngineRegistry {
 	registry.Register(NewCodexEngine())
 	registry.Register(NewCopilotEngine())
 	registry.Register(NewGeminiEngine())
+	registry.Register(NewOpenCodeEngine())
 
 	agenticEngineLog.Printf("Registered %d engines", len(registry.engines))
 	return registry

pkg/workflow/data/engines/opencode.md

@@ -0,0 +1,16 @@
+---
+engine:
+  id: opencode
+  display-name: OpenCode
+  description: OpenCode CLI with headless mode and multi-provider LLM support
+  runtime-id: opencode
+  provider:
+    name: opencode
+  auth:
+    - role: api-key
+      secret: ANTHROPIC_API_KEY
+---
+
+<!-- # OpenCode CLI
+
+Shared engine configuration for OpenCode multi-provider AI coding agent (BYOK). -->