OpenCode Claude Hooks

Claude Code hooks compatibility for OpenCode

This OpenCode plugin enables you to use your existing Claude Code hook configurations with OpenCode, providing ~80% compatibility for drop-in migration.

Features

• ✅ Drop-in compatibility - Use your existing .claude/settings.json files
• ✅ All major hooks supported - SessionStart, SessionEnd, PreToolUse, PostToolUse, etc.
• ✅ Command and prompt-based hooks - Run shell scripts or use LLM-based decisions
• ✅ Multiple config locations - Project and global configurations
• ✅ Tool pattern matching - Target specific tools with regex patterns

Installation

npm install opencode-claude-hooks
# or
bun add opencode-claude-hooks

Add to your OpenCode configuration (~/.config/opencode/opencode.json):

{
  "$schema": "https://opencode.ai/config.json",
  "plugin": [
    "opencode-claude-hooks"
  ]
}

Configuration

The plugin loads hook configurations from these locations (in priority order):

Claude Code locations (for compatibility):

1. .claude/settings.local.json (project, not committed)
2. .claude/settings.json (project)
3. ~/.claude/settings.json (user global)

OpenCode locations: 4. .opencode/hooks.json (project) 5. ~/.config/opencode/hooks.json (user global)

All configurations are merged, with earlier files taking precedence.

Hook Configuration Format

{
  "hooks": {
    "PreToolUse": [
      {
        "matcher": "Bash",
        "hooks": [
          {
            "type": "command",
            "command": "bash ./scripts/validate-command.sh",
            "timeout": 5000
          }
        ]
      }
    ],
    "SessionStart": [
      {
        "hooks": [
          {
            "type": "command",
            "command": "echo 'Session started!'"
          }
        ]
      }
    ]
  }
}

Supported Hooks

Claude Code Hook	OpenCode Event	Compatibility
SessionStart	session.created	✅ Full
SessionEnd	session.deleted	✅ Full
PreToolUse	tool.execute.before	✅ Full
PostToolUse	tool.execute.after	✅ Full
PostToolUseFailure	tool.execute.after (error)	✅ Full
PermissionRequest	permission.asked	⚠️ Partial
SubagentStart	tool.execute.before (Task)	⚠️ Partial
SubagentStop	tool.execute.after (Task)	⚠️ Partial
PreCompact	experimental.session.compacting	⚠️ Partial
UserPromptSubmit	message.updated (user)	⚠️ Partial
Stop	session.idle	⚠️ Partial
Notification	tui.toast.show	⚠️ Partial
Setup	N/A	❌ Not supported

Hook Types

Command Hooks

Execute shell commands with stdin/stdout:

{
  "type": "command",
  "command": "bash ./my-hook.sh",
  "timeout": 5000
}

Input via stdin:

{
  "session_id": "abc123",
  "transcript_path": "/path/to/transcript.jsonl",
  "cwd": "/project/directory",
  "permission_mode": "default",
  "hook_event_name": "PreToolUse",
  "tool_name": "Bash",
  "tool_input": { "command": "ls" }
}

Exit codes:

• 0 - Success, continue
• 2 - Block/deny the action
• Other - Non-blocking error

JSON output (optional):

{
  "hookSpecificOutput": {
    "hookEventName": "PreToolUse",
    "permissionDecision": "deny",
    "permissionDecisionReason": "Dangerous command detected"
  }
}

Prompt-Based Hooks

Use LLM to make decisions:

{
  "type": "prompt",
  "prompt": "Check if this bash command is safe to execute"
}

Tool Pattern Matching

Use the matcher field to target specific tools:

• "*" or "" - Matches all tools
• "Bash" - Exact match
• "Edit|Write" - Regex pattern (matches Edit OR Write)
• "Read.*" - Regex with wildcards

Examples

See the examples/ directory for complete hook examples:

• session-start.sh - Log session starts with timestamp
• block-dangerous-bash.sh - Block dangerous bash commands
• pre-tool-use-logger.sh - Log all tool executions
• notify-on-write.sh - macOS notification when files are written

Environment Variables

Hooks receive these environment variables:

• CLAUDE_PROJECT_DIR - Project root directory
• OPENCODE_COMPAT - Set to "true" (indicates OpenCode environment)

Limitations

1. Setup hook - No equivalent in OpenCode
2. MCP tools - May not trigger plugin hooks
3. Timing differences - Stop and PreCompact semantics differ slightly
4. Permission model - OpenCode's permission system works differently

Development

# Install dependencies
bun install

# Build
bun run build

# Type check
bun run typecheck

# Test hooks locally
bun run examples/test-runner.ts

License

MIT

Contributing

Contributions welcome! Please open an issue or PR.

Related

• Claude Code
• OpenCode
• OpenCode Plugin API