Comprehensive lifecycle hook patterns for Claude Code workflows. Use when configuring PreToolUse, PostToolUse, UserPromptSubmit, Stop, or SubagentStop hooks. Covers hook matchers, command hooks, prompt hooks, validation, metrics, auto-formatting, and security patterns. Trigger keywords - "hooks", "PreToolUse", "PostToolUse", "lifecycle", "tool matcher", "hook template", "auto-format", "security hook", "validation hook".
View on GitHubFebruary 5, 2026
Select agents to install to:
npx add-skill https://github.com/MadAppGang/claude-code/blob/main/plugins/multimodel/skills/hooks-system/SKILL.md -a claude-code --skill hooks-systemInstallation paths:
.claude/skills/hooks-system/# Hooks System **Version:** 1.0.0 **Purpose:** Lifecycle hook patterns for validation, automation, security, and metrics in Claude Code workflows **Status:** Production Ready ## Overview Hooks are lifecycle callbacks that execute at specific points in the Claude Code workflow. They enable: - **Validation** (block dangerous operations before execution) - **Automation** (auto-format code after file changes) - **Security** (enforce safety policies on commands and tools) - **Metrics** (track tool usage, performance, costs) - **Quality Control** (run tests after implementation changes) - **Context Injection** (load project-specific context at session start) Hooks transform Claude Code from a reactive assistant into a **proactive, policy-enforced development environment**. --- ## Hook Types Reference Claude Code provides 7 hook types that fire at different lifecycle stages: | Hook Type | When It Fires | Receives | Can Modify | Use Cases | |-----------|---------------|----------|------------|-----------| | **PreToolUse** | Before tool execution | Tool name, input | Tool input, can block | Validation, security checks, permission gates | | **PostToolUse** | After tool completion | Tool name, input, output | Nothing (read-only) | Auto-format, metrics, notifications | | **UserPromptSubmit** | User submits prompt | Prompt text | Nothing (read-only) | Complexity analysis, model routing, context injection | | **SessionStart** | Session begins | Session metadata | Nothing (read-only) | Load project context, initialize environment | | **Stop** | Main session stops | Session metadata | Nothing (read-only) | Completion validation, cleanup, final reports | | **SubagentStop** | Sub-agent (Task) completes | Task metadata, output | Nothing (read-only) | Task metrics, result validation | | **Notification** | System notification | Notification data | Nothing (read-only) | Alert logging, external integrations | | **PermissionRequest** | Tool needs permission | Tool name, action | No