Hooks

Full language page — every event, condition, action, their params, the templating variables, and verified examples: Hooks.

Always quote YAML "on" (bare on: is YAML boolean true). Condition and action params are inline (siblings of type), not nested under params:.

Events that fire: turn_start (user_prompt), turn_end, stop (pre_finish), tool_start (pre_tool_use), tool_end (post_tool_use), session_start, session_end, pre_compact, error, approval_request.

Declared but not emitted in this build (a hook on them compiles with warning DGT-W0006 and never fires): agent_spawn, agent_complete (multi-agent not implemented), activation (declared-only, unrouted).

yaml

runtime:
  hooks:
    - id: auto-compact
      "on": turn_end
      condition:
        type: context_pressure
        threshold: 0.80
      action:
        type: compact_context
      cooldown: 60