Automated summary
A guide for developing Claude Code hooks, shell scripts that execute automatically in response to tool calls, notifications, session events, and more.
Strengths
- Enables automation of workflows like linting, formatting, notifications, and custom validations.
- Supports a wide range of events (PreToolUse, PostToolUse, SessionStart, etc.).
- Provides environment variables for flexible integration with the project.
- Recommends prompt-based hooks for complex, context-aware logic.
Limitations
- Requires a good understanding of event types and execution order.
- Command hooks are limited to simple deterministic checks.
- Manual handling of timeouts and error states is necessary.
When you need to enforce policies, automate repetitive tasks, or integrate external tools into Claude Code workflows.
For simple one-off customizations, directly instructing the agent in the prompt is more straightforward.
Security analysis
SafeThe skill is purely a documentation guide for developing hooks. It does not instruct any code execution or dangerous operations.
No concerns found
How this analysis is madeExamples
Create a hook that runs eslint on any JavaScript file before it is used by Claude. Use PreToolUse event and only trigger when the tool is reading or writing a .js file.I want a hook that loads a summary of the current project from a README file every time a new session starts. Use the SessionStart event and store context in an environment variable.My PostToolUse hook that logs tool calls isn't firing. Check my hook configuration and help me debug the event listener setup.name: hook-development description: "[Utility] Guide for developing Claude Code hooks - shell commands that execute automatically in response to tool calls and notifications. Use this when users want to create, debug, or optimize hooks for automating workflows like linting, formatting, notifications, or custom validations. Supports PreToolUse, PostToolUse, Stop, SubagentStop, SessionStart, SessionEnd, UserPromptSubmit, PreCompact, Notification events."
Hook Development for Claude Code Plugins
Overview
Hooks are event-driven automation scripts that execute in response to Claude Code events. Use hooks to validate operations, enforce policies, add context, and integrate external tools into workflows.
Hook Types
Prompt-Based Hooks (Recommended)
Use LLM-driven decision making for context-aware validation.
Command Hooks
Execute bash commands for deterministic checks.
Hook Events
| Event | When | Use For | |-------|------|---------| | PreToolUse | Before tool | Validation, modification | | PostToolUse | After tool | Feedback, logging | | UserPromptSubmit | User input | Context, validation | | Stop | Agent stopping | Completeness check | | SubagentStop | Subagent done | Task validation | | SessionStart | Session begins | Context loading | | SessionEnd | Session ends | Cleanup, logging | | PreCompact | Before compact | Preserve context | | Notification | User notified | Logging, reactions |
Environment Variables
$CLAUDE_PROJECT_DIR- Project root path$CLAUDE_PLUGIN_ROOT- Plugin directory$CLAUDE_ENV_FILE- SessionStart only: persist env vars here
Best Practices
- Use prompt-based hooks for complex logic
- Use ${CLAUDE_PLUGIN_ROOT} for portability
- Validate all inputs in command hooks
- Set appropriate timeouts
From the file to a first result
The download contains exactly the content displayed on this page. This copy may differ from the latest version in the source repository.
View the source and supporting filesThis download contains SKILL.md only. Any scripts, references, templates and dependencies are not included. Get the required files from the source, preserving their directory structure, before continuing.
1. Download the file
Download SKILL.mdFrom the root of a test project, save the file as .skill-downloads/hook-development-for-claude-code-mm5t8a3g/SKILL.md, or use the command below. This folder is for inspecting the skill before installation.
Command for macOS/Linux or WSL: requires a POSIX shell and curl. On Windows without WSL, use the download button and create the folder manually.
mkdir -p '.skill-downloads/hook-development-for-claude-code-mm5t8a3g' && curl --fail --show-error --location 'https://skills-guides.com/api/skills/hook-development-for-claude-code-mm5t8a3g/download' --output '.skill-downloads/hook-development-for-claude-code-mm5t8a3g/SKILL.md.part' && mv '.skill-downloads/hook-development-for-claude-code-mm5t8a3g/SKILL.md.part' '.skill-downloads/hook-development-for-claude-code-mm5t8a3g/SKILL.md'2. Check prerequisites
Read SKILL.md before using it. If it references scripts or external services, inspect them and prepare the required access in your test environment.
No recognized prerequisites section in this file. This does not mean it is self-contained: libraries, tools and access requirements may be mentioned elsewhere in the content or source repository.
The platforms on this page are catalog indications. The paths below follow tool documentation; they do not prove this skill has been run in those tools. No minimum tool version is confirmed for this listing.
3. Load the skill
After inspection, copy the complete folder into your project using one of the commands below, then open a new tool session. The command stops if a folder with the same name already exists: compare the files before replacing it.
Claude Code
test -f '.skill-downloads/hook-development-for-claude-code-mm5t8a3g/SKILL.md' && test -s '.skill-downloads/hook-development-for-claude-code-mm5t8a3g/SKILL.md' && mkdir -p '.claude/skills' && test ! -e '.claude/skills/hook-development' && cp -R '.skill-downloads/hook-development-for-claude-code-mm5t8a3g' '.claude/skills/hook-development'OpenSkills
OpenSkills must already be installed. The local install/read procedure is checked with OpenSkills 1.5.0, which requires Node.js ≥ 20.6.0. Catalog slugs are not resolved automatically.
Official OpenSkills installationopenskills install './.skill-downloads/hook-development-for-claude-code-mm5t8a3g'openskills read 'hook-development-for-claude-code-mm5t8a3g'Reading should display the installed file content and its base directory. It does not run the skill or install its dependencies.
For an agent that reads AGENTS.md, then sync the index. This command changes AGENTS.md: review the diff before using it.
openskills syncManual method or another tool: attach SKILL.md to a conversation, or open it in an agent that can read files. Include any required supporting resources. No universal folder is recognized by every tool.
4. Try a first task
Use a short, synthetic input: an API endpoint, a small document or an interface brief. In a new conversation, attach the file or give the agent its path, then adapt this request:
Read .skill-downloads/hook-development-for-claude-code-mm5t8a3g/SKILL.md and apply its instructions to this example: [describe a test input]. Identify any missing files, dependencies or access. Produce the result requested by the skill without inventing data or running unreviewed scripts.Expected result: output matching the skill instructions, or a precise list of missing prerequisites. A read confirmation alone does not validate a first use. If an external resource is unavailable, that path remains untested.
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