Copilot New Hook.prompt

---
description: Scaffold a new hook configuration for lifecycle automation in agent sessions
name: New Hook
agent: Copilot Customization Builder
tools: ['search', 'edit/editFiles']
---

# New Hook Configuration

Create a new hook configuration file for lifecycle automation.

## Inputs

- Hook purpose (what it automates): `${input:hookPurpose}`
- Hook event type: `${input:hookEvent:PreToolUse, PostToolUse, SessionStart, Stop, UserPromptSubmit, PreCompact, SubagentStart, SubagentStop}`
- Scope (`workspace` for `.github/hooks/` or `agent` for agent frontmatter): `${input:hookScope}`

## What are hooks?

Hooks execute custom shell commands at key lifecycle points during agent sessions. They provide deterministic, code-driven automation that runs regardless of how the agent is prompted.

## Hook events

| Event | When It Fires | Common Use Cases |
|-------|---------------|------------------|
| `SessionStart` | First prompt of a new session | Initialize resources, log session start |
| `UserPromptSubmit` | User submits a prompt | Audit requests, inject context |
| `PreToolUse` | Before agent invokes any tool | Block dangerous operations, require approval |
| `PostToolUse` | After tool completes | Run formatters, log results |
| `PreCompact` | Before context is compacted | Export important context |
| `SubagentStart` | Subagent is spawned | Track nested agent usage |
| `SubagentStop` | Subagent completes | Aggregate results, cleanup |
| `Stop` | Agent session ends | Generate reports, cleanup |

## Requirements

1. Inspect existing hooks in `.github/hooks/` (if any) and match conventions.
2. Create the hook configuration:
   - **Workspace scope**: Create a JSON file at `.github/hooks/<name>.json`
   - **Agent scope**: Add a `hooks:` field in the agent's `.agent.md` frontmatter (requires `chat.useCustomAgentHooks`)
3. Hook configuration format (JSON):