Hook Observer - Claude Code Plugin

A collection of Useful Claude Code tools and plugins by Tom Chen. For now it only contains the Hook Observer plugin.

中文

Hook Observer

A Claude Code plugin that captures all 22 hook events and logs them to ~/.claude/hook-observer-data/events.jsonl.

Useful for debugging hooks when developing plugins, keeping history, and learning how Claude Code works under the hood.

To view these events in a real-time web app, use my CC Friend (Claude Code Friend).

Install

claude plugin marketplace add cc-friend/claude-code-plugins
claude plugin install hook-observer@cc-friend

Architecture

Once installed, every Claude Code hook event is logged to ~/.claude/hook-observer-data/events.jsonl as JSONL (one JSON object per line), enriched with _observer metadata (event ID, timestamp).

Claude Code hook event (JSON via stdin)
        |
        v
scripts/hook-handler.js    Enriches with metadata, appends to JSONL
        |
        v
~/.claude/hook-observer-data/events.jsonl

• hook-handler.js: universal logger for 21 events. Reads JSON from stdin, enriches with _observer metadata (event_id, timestamp), appends to JSONL file. Exits 0 immediately.
• worktree-handler.js: WorktreeCreate passthrough. Logs the event, then runs git worktree add and prints the path to stdout.

All hooks run with async: true (except WorktreeCreate) so they never slow down Claude Code.

Supported Events

Category	Event	Description
Session	SessionStart	Session begins or resumes
Session	UserPromptSubmit	User submits a prompt
Session	SessionEnd	Session terminates
Tool	PreToolUse	Before a tool call executes
Tool	PostToolUse	After a tool call succeeds
Tool	PostToolUseFailure	After a tool call fails
Tool	PermissionRequest	Permission dialog appears
Stop	Stop	Claude finishes responding
Stop	StopFailure	Turn ends due to API error
Agent	SubagentStart	Subagent is spawned
Agent	SubagentStop	Subagent finishes
Agent	TeammateIdle	Teammate about to go idle
Task	TaskCompleted	Task marked as completed
Task	WorktreeCreate	Worktree being created
Task	WorktreeRemove	Worktree being removed
Config	InstructionsLoaded	CLAUDE.md file loaded
Config	ConfigChange	Settings file changed
Config	PreCompact	Before context compaction
Config	PostCompact	After compaction completes
MCP	Elicitation	MCP server requests input
MCP	ElicitationResult	User responds to MCP input
Notification	Notification	Claude Code sends notification

Uninstallation

claude plugin uninstall hook-observer

Development

claude --plugin-dir /path/to/claude-code-plugins/hook-observer

This loads the plugin for a single session without installing it (uninstallation would not be necessary).

License

MIT