update-hook

name	update-hook
description	Create, update, or manage universal-ai-config hook templates. Handles finding existing hooks, deciding whether to create or modify, and writing the template.

Manage Hook Templates

Hooks are lifecycle automation that triggers on specific events during AI sessions. They use JSON format (not markdown).

Finding Existing Hooks

List files in <%= hookTemplatePath() %>/ to discover existing hook templates (.json files). Read them to understand what events are already handled.

Note: Hooks from multiple files are merged by event name during generation. You can organize hooks by concern (e.g. linting.json, security.json).

Additional Template Directories

This project may have additional template directories configured via additionalTemplateDirs. To find them, search the project root for all config files matching universal-ai-config.* (e.g. universal-ai-config.config.ts, universal-ai-config.overrides.config.ts, and any other variants) and read the additionalTemplateDirs field from each. If the user asks to update a template that doesn't exist in the main templates directory, or explicitly refers to shared/global/external templates:

1. Read all universal-ai-config.* config files in the project root to find additionalTemplateDirs paths
2. Search those directories for the relevant hook file
3. IMPORTANT: Before editing any file outside the main <%= config.templatesDir %>/ directory, ask the user for explicit confirmation — these are shared templates that may affect other projects

Deciding What to Do

• Create new file: for an entirely new concern or automation area
• Update existing file: modify handlers or add events to an existing hook file
• Merge strategy: since hooks merge by event, you can split hooks across files for better organization without conflicts
• Delete: remove a hook file when the automation is no longer needed

Creating a New Hook

1. Create a .json file in <%= hookTemplatePath() %>/ with a descriptive name (e.g. linting.json)
2. Use the standard hook JSON structure

JSON Structure

{
  "hooks": {
    "eventName": [
      {
        "command": "path/to/script.sh",
        "matcher": "ToolName",
        "timeout": 30,
        "description": "What this hook does"
      }
    ]
  }
}

Events, Handler Fields, and Per-Target Overrides

See the Hooks section in <%= instructionPath('uac-template-guide') %> for the complete reference: all 13 universal event names, handler fields (command, matcher, timeout, description), event name mappings per target, and per-target override syntax.

Use camelCase event names (e.g. sessionStart, preToolUse, postToolUse). The CLI maps them to each target's format and silently drops unsupported events.

Example

{
  "hooks": {
    "postToolUse": [
      {
        "matcher": "Write|Edit",
        "command": "./scripts/format-file.sh",
        "timeout": 60,
        "description": "Auto-format files after edits"
      }
    ],
    "sessionStart": [
      {
        "command": "echo 'Session started at $(date)'",
        "description": "Log session start"
      }
    ]
  }
}

After Changes

Run uac generate to regenerate target-specific config files and verify the output.

Reminder: Always edit templates in <%= hookTemplatePath() %>/ — never edit generated target-specific files directly.