Claude Hooks¶

What it is¶

Claude hooks are community patterns and scripts that run around Claude Code sessions to add policy checks, notifications, automation, and guardrails. They act as "middleware" for agentic coding.

What problem it solves¶

They let teams enforce workflow behavior outside the model prompt itself, which is often more reliable for guardrails and repetitive operational glue. They bridge the gap between an autonomous agent and the deterministic requirements of a production CI/CD pipeline or security policy.

Where it fits in the stack¶

Development & Ops / Workflow Guardrails. Hooks sit around the coding-agent loop (Pre-execution and Post-execution) rather than inside the generated output.

Typical use cases¶

Pre-Commit Linting: Automatically running eslint or prettier before the agent considers a task "done".
Security Scanning: Checking for leaked secrets in the code generated by the agent.
Workflow Notifications: Sending a Slack message when the agent finishes a long-running refactor.

Strengths¶

Reliability: Deterministic enforcement of rules (unlike prompts).
Automation: Reduces the "babysitting" required for autonomous agents.
Observability: Hooks provide clear logs of what happened before and after agent actions.

Limitations¶

Complexity: Setting up a robust hook system requires additional DevOps effort.
Maintenance: Hooks can break if the agent's CLI interface changes or if the repo structure evolves.

When to use it¶

When you need repeatable, deterministic guardrails around agent execution.
When integrating agents into a shared team environment with strict standards.
When you want to automate the "feedback loop" (e.g., auto-running tests after a change).

When not to use it¶

When prompt instructions are sufficient and simplicity matters more.
In very early-stage exploration where strict rules might hinder the agent's creativity.

Technical examples¶

Pre-Execution Policy Check¶

A simple Python script to check if the repository is in a "clean" state before allowing Claude to work.

import subprocess
import sys

def check_git_status():
    status = subprocess.check_output(["git", "status", "--porcelain"]).decode("utf-8")
    if status:
        print("Error: Repository has uncommitted changes. Please clean up before starting Claude.")
        sys.exit(1)

if __name__ == "__main__":
    check_git_status()
    print("Pre-check passed: Repo is clean.")

Post-Execution Test Runner¶

A Bash hook that runs tests and reports back to the agent (or a log file).

#!/bin/bash

# Run the test suite
npm test > test_output.log 2>&1

if [ $? -eq 0 ]; then
    echo "Tests passed successfully."
else
    echo "Tests failed. See test_output.log for details."
    # Optionally: trigger an alert or a re-prompt
fi

Practical Implementation¶

Most hooks are implemented as wrapper scripts around the claude CLI:

# Example 'claude-safe' alias
alias claude-safe='python3 pre-hook.py && claude && bash post-hook.sh'

Automation: Slack Notification on Completion¶

A post-execution hook to notify the team via Slack webhook.

import os
import requests

def notify_slack(message):
    webhook_url = os.environ.get("SLACK_WEBHOOK_URL")
    if not webhook_url:
        return
    payload = {"text": message}
    requests.post(webhook_url, json=payload)

if __name__ == "__main__":
    notify_slack("Claude Code session completed in repo: " + os.getcwd())

Sources / References¶

Contribution Metadata¶

Last reviewed: 2026-05-15
Confidence: high