Hooks

What metraton-gaia runs automatically, and when. A hook is a command Claude Code fires at a fixed moment, without you asking for it.

metraton@metraton

GitHub

Install

$ npx -y skills add metraton/gaia --agent claude-code

Ships with metraton-gaia. Installing the plugin gets these hooks.

What fires, and when

PreToolUse

Runs pre_tool_use.py.

PostToolUse

Runs post_tool_use.py.

SubagentStop

Runs subagent_stop.py.

SessionStart

Fires once when a session begins, and again after a context compaction. It is where a plugin sets up its environment, or restores state the compaction dropped.

Runs session_start.py.

SessionEnd

Runs session_end_hook.py.

PreCompact

Runs pre_compact.py.

PostCompact

Runs post_compact.py.

Stop

Runs stop_hook.py.

TaskCompleted

Runs task_completed.py.

SubagentStart

Runs subagent_start.py.

UserPromptSubmit

Fires before Claude sees each prompt you send. A plugin can use it to inject context, so the same instruction reaches the model every turn instead of only at session start.