Hook Valid Event Types

Hook event keys in .claude/settings.json MUST use recognized Claude Code event type names (29 events as of 2026-04-29). Unrecognized event names are silently ignored, so a typo like "PreTooluse" (lowercase u) means the hook never fires.

Antipatterns

• Camel-case typos. Writing "PreTooluse" (lowercase u) or "postToolUse" (lowercase p) instead of the exact PascalCase names. Claude Code silently ignores unrecognized keys.
• Inventing event names. Using names like "onToolUse", "before_tool", or "AfterEdit" that follow familiar conventions but aren't recognized by Claude Code.
• Legacy or deprecated names. Using event names from older Claude Code versions that have since been renamed or removed. The valid set changes across versions.

Pass / Fail

Pass

{
  "hooks": {
    "PreToolUse": [{ "type": "command", "command": "echo pre" }],
    "PostToolUse": [{ "type": "command", "command": "echo post" }],
    "Stop": [{ "type": "command", "command": "./cleanup.sh" }]
  }
}

Fail

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

Limitations

Only checks that at least one recognized event type is present. Does not detect misspelled event names if a valid one also exists.