hooks-builder

hooks-builder is a skill for Claude Code from mike-coulbourn/claude-vibes. It costs 65 tokens per session (3,295 once invoked), scanned B, original, MIT.

A guide for creating event-driven hooks in Claude Code. Hooks are scripts or rules that run when events such as tool use, session start, or prompt submission occur.

In plain words
What is it for?
Use it to configure pre- and post-tool checks, permission controls, input validation, security rules, notifications, and session automation in settings.json.
Why use it?
It explains how to check or control agent actions at specific points in a session. This can enforce policies, reject unsafe tool calls, and run follow-up processing automatically.

Skill for Claude Code

Written for Claude Code: $CLAUDE_PROJECT_DIR variable. Also seen: reads .claude/ paths; mentions subagents; names the AskUserQuestion tool.

Runs only inside its plugin — its command needs a path that Claude Code sets for a plugin’s own hooks and for nothing else. Install the plugin, not this.

Part of the claude-vibes plugin — 24 skills shipped together

Good fit Use it to configure pre- and post-tool checks, permission controls, input validation, security rules, notifications, and session automation in settings.json.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code
/plugin marketplace add mike-coulbourn/claude-vibes
Claude Code
/plugin install claude-vibes

Made for: Claude Code.

Or install claude-vibes, the plugin that ships this one along with the rest of its 24 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for hooks-builder

README.md
[![agentmods](https://agentmods.dev/badge/skills/mike-coulbourn/claude-vibes/hooks-builder/github.svg)](https://agentmods.dev/skills/mike-coulbourn/claude-vibes/hooks-builder)
Your own site
<a href="https://agentmods.dev/skills/mike-coulbourn/claude-vibes/hooks-builder"><img src="https://agentmods.dev/badge/skills/mike-coulbourn/claude-vibes/hooks-builder/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for hooks-builder

Your own site · 80×15
<a href="https://agentmods.dev/skills/mike-coulbourn/claude-vibes/hooks-builder"><img src="https://agentmods.dev/badge/skills/mike-coulbourn/claude-vibes/hooks-builder.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 65 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,295 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 3 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00065 $0.03295
Opus 5 $0.00032 $0.01648
Sonnet 5 $0.00013 $0.00659
Haiku 4.5 $0.00006 $0.00330

Measured 10d ago against content hash cfe088d36f25, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade B, and why

hooks-builder scanned grade B with 3 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Asks for rootlowPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

- [ ] No sudo or privilege escalation

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

Reads agent configuration directorieslowAgent snooping

.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.

~/.claude/settings.json → Personal hooks (all projects)

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

Recursive force deletemediumDestructive command

rm -rf with a variable or a broad path is one typo away from removing the wrong tree.

- Malicious inputs: `{"tool_input": {"file_path": "; rm -rf /"}}`

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

plugins/vibes/skills/hooks-builder/SKILL.md · 509 lines

How it starts

The opening of the file, as written. The whole thing — 509 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Hooks Builder

A comprehensive guide for creating Claude Code hooks — event-driven automation that monitors and controls Claude's actions.

Quick Reference

The 10 Hook Events

Event When It Fires Can Block? Supports Matchers?
PreToolUse Before tool executes YES YES (tool names)
PermissionRequest Permission dialog shown YES YES (tool names)
PostToolUse After tool succeeds No YES (tool names)
Notification Claude sends notification No YES
UserPromptSubmit User submits prompt YES No
Stop Claude finishes responding Can force continue No
SubagentStop Subagent finishes Can force continue No
PreCompact Before context compaction No YES (manual/auto)
SessionStart Session begins No YES (startup/resume/clear/compact)
SessionEnd Session ends No No

Exit Code Semantics

Exit Code Meaning Effect
0 Success stdout parsed as JSON for control
2 Blocking error VETO — stderr shown to Claude
Other Non-blocking error stderr logged in debug mode

Configuration Locations

~/.claude/settings.json          → Personal hooks (all projects)
.claude/settings.json            → Project hooks (team, committed)
.claude/settings.local.json      → Local overrides (not committed)

Essential Environment Variables

Variable Description
$CLAUDE_PROJECT_DIR Project root directory
$CLAUDE_CODE_REMOTE Remote/local indicator
$CLAUDE_ENV_FILE Environment persistence path (SessionStart)
$CLAUDE_PLUGIN_ROOT Plugin directory (plugin hooks)

Key Commands

/hooks              # View active hooks
claude --debug      # Enable debug logging
chmod +x script.sh  # Make script executable

6-Phase Workflow

Phase 1: Requirements Gathering

Read the full file on GitHub · 509 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 10d ago First seen · 509 lines · 65 tokens per session scan B cfe088d36f25

Subscribe to this mod's changes

hooks-builder is a skill published in the GitHub repository mike-coulbourn/claude-vibes (39 stars, last pushed 8mo ago), licensed MIT. It adds 65 tokens to every session and 3,295 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it B with 3 findings (asks for root, reads agent configuration directories, recursive force delete). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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