Hook Valid Event Types

Hook event keys in .gemini/settings.json MUST use recognized hook event type names (11 events). Unrecognized event names are silently ignored, so a typo means the hook never fires. Antigravity keeps the Hooks surface from Gemini CLI; the event-type set here is inherited pending published Antigravity hook docs.

Antipatterns

• Camel-case typos. Writing event names with wrong capitalization. The agent silently ignores unrecognized keys.
• Cross-agent event names. Using event names from another agent (e.g., Claude's PreToolUse instead of the .gemini/settings.json convention).
• Deprecated event names. Using event names from older versions that have been renamed or removed.

Pass / Fail

Pass

{
  "hooks": {
    "SessionStart": [{ "type": "command", "command": "echo hook" }]
  }
}

Fail

{
  "hooks": {
    "onToolUse": [{ "type": "command", "command": "echo hook" }]
  }
}

Limitations

Checks that at least one recognized event type is present. Does not detect misspelled event names if a valid one also exists. The event-type set is inherited from Gemini CLI pending accessible Antigravity hook documentation.