Hooks Eval

When NOT To Use

• Writing a new hook (use abstract:hook-authoring)
• Evaluating skills (use abstract:skills-eval)
• Evaluating rules in .claude/rules/ (use abstract:rules-eval)

Table of Contents

• Overview
• Key Capabilities
• Core Components
• Quick Reference
• Hook Event Types
• Hook Callback Signature
• Return Values
• Quality Scoring (100 points)
• Detailed Resources
• Basic Evaluation Workflow
• Integration with Other Tools
• Related Skills

Hooks Evaluation Framework

Overview

This skill provides a detailed framework for evaluating, auditing, and implementing Claude Code hooks across all scopes (plugin, project, global) and both JSON-based and programmatic (Python SDK) hooks.

Key Capabilities

• Security Analysis: Vulnerability scanning, dangerous pattern detection, injection prevention
• Performance Analysis: Execution time benchmarking, resource usage, optimization
• Compliance Checking: Structure validation, documentation requirements, best practices
• SDK Integration: Python SDK hook types, callbacks, matchers, and patterns

Core Components

Quick Reference

Hook Event Types

HookEvent = Literal[
    "PreToolUse",  # Before tool execution
    "PostToolUse",  # After tool execution
    "UserPromptSubmit",  # When user submits prompt
    "Stop",  # When stopping execution
    "SubagentStop",  # When a subagent stops
    "TeammateIdle",  # When teammate agent becomes idle (2.1.33+)
    "TaskCompleted",  # When a task finishes execution (2.1.33+)
    "PreCompact",  # Before message compaction
]

Verification: Run the command with --help flag to verify availability.

Note: Python SDK does not support SessionStart, SessionEnd, or Notification hooks due to setup limitations. However, plugins can define SessionStart hooks via hooks.json using shell commands (e.g., leyline's detect-git-platform.sh).

Plugin-Level hooks.json

Plugins can declare hooks via "hooks": "./hooks/hooks.json" in plugin.json. The evaluator validates:

• Referenced hooks.json exists and is valid JSON
• Shell commands referenced in hooks exist and are executable
• Hook matchers use valid event types

Hook Callback Signature

async def my_hook(
    input_data: dict[str, Any],  # Hook-specific input
    tool_use_id: str | None,  # Tool ID (for tool hooks)
    context: HookContext,  # Additional context
) -> dict[str, Any]:  # Return decision/messages
    ...

Verification: Run the command with --help flag to verify availability.

Return Values

return {
    "hookSpecificOutput": {
        "hookEventName": "PreToolUse",  # Match hook type
        "permissionDecision": "deny",  # Optional: block action
        "permissionDecisionReason": "...",  # Reason for denial
        "additionalContext": "...",  # Optional: context added
    }
}

Verification: Run the command with --help flag to verify availability.

Quality Scoring (100 points)

Detailed Resources

• SDK Hook Types: See modules/sdk-hook-types.md for complete Python SDK type definitions, patterns, and examples
• Evaluation Criteria: See modules/evaluation-criteria.md for detailed scoring rubric and quality gates
• Security Patterns: See modules/sdk-hook-types.md for vulnerability detection and mitigation
• Performance Guide: See modules/evaluation-criteria.md for benchmarking and optimization

Basic Evaluation Workflow

# 1. Run detailed evaluation
/hooks-eval --detailed

# 2. Focus on security issues
/hooks-eval --security-only --format sarif

# 3. Benchmark performance
/hooks-eval --performance-baseline

# 4. Check compliance
/hooks-eval --compliance-report

Verification: Run the command with --help flag to verify availability.

Integration with Other Tools

# Complete plugin evaluation pipeline
/hooks-eval --detailed          # Evaluate all hooks
/analyze-hook hooks/specific.py      # Deep-dive on one hook
/validate-plugin .                   # Validate overall structure

Verification: Run the command with --help flag to verify availability.

Related Skills

• abstract:hook-scope-guide - Decide where to place hooks (plugin/project/global)
• abstract:hook-authoring - Write hook rules and patterns
• abstract:validate-plugin - Validate complete plugin structure

Troubleshooting

Common Issues

Hook not firing Verify hook pattern matches the event. Check hook logs for errors

Syntax errors Validate JSON/Python syntax before deployment

Permission denied Check hook file permissions and ownership

Exit Criteria

• Every hook in scope receives a composite quality score (0-100) across the five weighted categories: Security (30), Performance (25), Compliance (20), Reliability (15), Maintainability (10).
• Any hook scoring below 60 on the Security category is flagged as a blocking issue before the evaluation report is returned.
• Shell commands referenced in hooks.json are verified to exist and be executable; missing scripts are listed as FAIL findings.
• The evaluation report distinguishes between JSON hooks (Claude Code) and Python SDK hooks and applies the correct signature expectations for each type.