Claude Hooks

Claude Code Hooks and GitHub Workflows System

Purpose

This system automates the ESLint rule development lifecycle using Claude Code Hooks for local quality enforcement and GitHub Workflows for triggering agents on issue events.

Why the System Was Built

Automation reduces manual toil by enforcing local quality gates and launching background agents so repetitive rule work does not block developers.

Architecture Overview

┌─────────────────────────────────────────────────────────────────────────────┐
│                            GitHub Issue Created                              │
│                          (with rule-request label)                           │
└─────────────────────────────────────────────────────────────────────────────┘
                                      │
                                      ▼
┌─────────────────────────────────────────────────────────────────────────────┐
│               claude-rule-research-agent.yml (claude-research)               │
│     • Searches web for existing ESLint rules                                 │
│     • Posts findings as issue comment                                        │
│     • Labels: research-complete, claude-implement (if NO MATCH)              │
└─────────────────────────────────────────────────────────────────────────────┘
                                      │
                        (if NO MATCH → claude-implement)
                                      │
                                      ▼
┌─────────────────────────────────────────────────────────────────────────────┐
│             claude-implement-rule-agent.yml (claude-implement)               │
│     • Creates new branch from develop                                        │
│     • Implements rule using .claude/agents/implement-rule.md               │
│     • Claude Code Hooks enforce quality (build, lint, tests, structure)    │
│     • Opens PR on completion                                                 │
└─────────────────────────────────────────────────────────────────────────────┘

Definitions

Core Components

• Claude Code Hooks: Local lifecycle scripts that enforce lint/build/test and prompt tracking on every agent run.
• GitHub Workflows: Issue and review triggers that launch background agents for research, implementation, and bug fixes.
• Validation Layers: Stop hook checks that gate completion on build, lint, tests, and rule structure for reliability.
• Change Log: Per-session file tracking that keeps prompts idempotent and resumes validation across loops.

How It Makes Developers' Lives Easier

• Automated quality gates prevent manual babysitting of lint/build/test steps.
• Structured prompts and rule scaffolding reduce errors and keep implementations consistent.
• Loop prevention and concurrency controls avoid duplicated agent runs and wasted API cycles.

Directory Structure

.claude/
├── settings.json                        # Hook configuration
├── hooks/
│   ├── stop.sh                          # Stop hook entry point
│   ├── track-changes.sh                 # File change tracking
│   ├── track-prompt.sh                  # Prompt tracking & rule-request detection
│   └── skill-activation-llm-eval.sh    # Forces explicit skill evaluation
├── agents/
│   ├── implement-rule.md                # New rule implementation guide
│   └── fix-bug.md                       # Bug fix guide
├── skills/
│   ├── task-completion-standards/SKILL.md  # Quality checklist
│   └── claude-hooks/SKILL.md           # This documentation
└── tmp/
    └── hooks/
        └── agent-change-log.json        # Auto-created change log

scripts/
├── check-merge-conflicts.sh          # Lists remaining conflicted files (merge conflict stop hook)
├── claude-hooks/
│   ├── agent-check.ts                   # Main stop hook logic
│   ├── change-log.ts                    # Change log utilities
│   ├── lint-diff.ts                     # Lint changed files only
│   ├── merge-conflict-check.ts          # Merge conflict stop logic (Priority 0)
│   ├── pr-review-check.ts               # PR review comment check for stop hook (Priority 1)
│   ├── track-changes.ts                 # Track file modifications
│   ├── track-prompt.ts                  # Track prompts & detect flags
│   ├── types.ts                         # Shared TypeScript types
│   └── validate-rule-structure.ts       # Validate rule has all files
├── cli/
│   ├── git-utils.ts                     # Git CLI utilities
│   └── git-merge/                       # Merge-conflict context utilities
│       ├── types.ts
│       ├── isInMergeConflictState.ts
│       ├── getConflictedFiles.ts
│       ├── getMergeBase.ts
│       ├── getSquashedDiff.ts
│       ├── getBranchLastCommitDate.ts
│       ├── getAssociatedPr.ts
│       ├── fetchPrMetadata.ts
│       └── buildMergeContext.ts
└── github/
    └── post-research-comment.ts         # Post research findings to issue

.github/workflows/
├── claude-rule-research-agent.yml       # Research existing rules
├── claude-implement-rule-agent.yml      # Implement new rules
└── claude-fix-bug-agent.yml             # Fix bugs in rules

GitHub Labels

Workflow Details

1. Research Workflow (claude-rule-research-agent.yml)

Trigger: Issue labeled with claude-research

Purpose: Search for existing ESLint rules before implementing

Flow:

1. Check if research comment already exists (short-circuit)
2. Launch agent to search web
3. Agent writes findings to .claude/tmp/research-results.md
4. Agent runs post-research-comment.ts which:
   • Posts findings as issue comment
   • Removes claude-research label
   • Adds research-complete label
   • If NO MATCH: Adds claude-implement label

2. Implementation Workflow (claude-implement-rule-agent.yml)

Trigger: Issue labeled with claude-implement (requires rule-request + research-complete)

Purpose: Implement new ESLint rule

Flow:

1. Create branch: develop-implement-rule-{issue_number}
2. Build prompt from .claude/agents/implement-rule.md + issue body
3. Include <!-- rule-request --> flag for expanded test prompts
4. Launch Claude Code agent
5. Claude Code Hooks enforce quality until completion
6. Open PR targeting develop

3. Bug Fix Workflow (claude-fix-bug-agent.yml)

Trigger: Issue labeled with claude-fix (requires bug)

Purpose: Fix bugs in existing rules

Flow:

1. Create branch: develop-fix-bug-{issue_number}
2. Build prompt from .claude/agents/fix-bug.md + issue body
3. No <!-- rule-request --> flag (skip expanded test prompts)
4. Launch Claude Code agent
5. Claude Code Hooks enforce quality until completion
6. Open PR targeting develop

Claude Code Hooks System

Hook Configuration (.claude/settings.json)

{
  "hooks": {
    "PostToolUse": [
      {
        "matcher": "Edit|Write",
        "hooks": [{ "type": "command", "command": ".claude/hooks/track-changes.sh" }]
      }
    ],
    "UserPromptSubmit": [
      {
        "hooks": [
          { "type": "command", "command": ".claude/hooks/track-prompt.sh" },
          { "type": "command", "command": ".claude/hooks/skill-activation-llm-eval.sh" }
        ]
      }
    ],
    "Stop": [
      {
        "hooks": [{ "type": "command", "command": ".claude/hooks/stop.sh" }]
      }
    ]
  }
}

Hook Input/Output Formats

PostToolUse (track-changes):

{
  "session_id": "abc123",
  "tool_use_id": "tool_xyz",
  "tool_name": "Edit",
  "tool_input": { "file_path": "src/rules/my-rule.ts" },
  "cwd": "/path/to/repo"
}

UserPromptSubmit (track-prompt):

{
  "hook_event_name": "UserPromptSubmit",
  "session_id": "abc123",
  "prompt": "Implement the my-rule ESLint rule <!-- rule-request -->"
}

Output: {} (empty object allows prompt through)

Stop (agent-check):

{
  "session_id": "abc123",
  "transcript_path": "/tmp/transcript.jsonl",
  "permission_mode": "default",
  "hook_event_name": "Stop",
  "stop_hook_active": false
}

Output: { "decision": "block", "reason": "..." } to block, {} to allow stop.

Stop Hook Execution Order

1. Heartbeat Update: Record activity timestamp
2. Status Check: Skip checks if stop_hook_active === true (prevents infinite loops)
3. Merge Conflict Check (Priority 0): If a git merge is in progress and conflicts remain, block completion and provide a fresh conflict-resolution prompt. Use npm run address-merge-conflicts to generate the initial prompt.
4. PR Review Check (Priority 1): For PR review branches (*-review-pr-*), check for unresolved comments (see .claude/skills/automated-review-addressing/SKILL.md)
5. Build Validation: npm run build must succeed
6. Linting Validation: ESLint on changed files only
7. Test Validation: npm test must pass
8. Rule Structure Validation: For rule implementations, verify:
   • src/rules/{rule-name}.ts exists
   • src/tests/{rule-name}.test.ts exists
   • docs/rules/{rule-name}.md exists
   • src/index.ts updated in 3 places (import, config, rules)
   • README.md mentions the rule
9. Check-Your-Work Prompt: Self-review prompt
10. Expand Tests Prompt: For rule implementations only (requires 20+ tests)

Critical Insights for Maintainers

• Order is fail-fast by design: stop on build errors before lint/test to avoid long runs on broken builds, prevent expensive lint/test runs, and reduce agent API costs.
• Common pain points: flaky tests or slow lint/test runs can loop; rerun locally with the same commands in stop.sh and scope to changed files when possible.
• Rule structure validation loops if required files are missing or src/index.ts exports are incomplete; ensure all items in the checklist above exist before reruns.
• MAX_LOOPS in change-log.ts prevents infinite prompting; increase only when intentionally allowing longer runs.
• Hook side-effects cascade: PR review checks can short-circuit quality checks, and change-log updates influence later prompts; watch the console output to see which stage stopped the run.

Rule Request Detection

The <!-- rule-request --> flag in the first prompt marks conversations as rule implementations:

function detectRuleRequestFlag(prompt: string): boolean {
  return prompt.includes('<!-- rule-request -->');
}

This triggers the "Expand Tests" prompt after the first "Check Your Work" prompt.

Change Log Structure

.claude/tmp/hooks/agent-change-log.json:

{
  "session-abc123": {
    "_metadata": {
      "hasCheckWorkPrompted": true,
      "hasExpandTestsPrompted": false,
      "isRuleRequest": true,
      "lastUserMessage": "...",
      "endTimestamp": null,
      "lastActivityTimestamp": 1700000100000
    },
    "tool-use-xyz": ["src/rules/new-rule.ts", "src/tests/new-rule.test.ts"]
  }
}

Quality Enforcement

Required Files for New Rules

1. src/rules/{rule-name}.ts - Rule implementation
2. src/tests/{rule-name}.test.ts - Test suite (20+ tests required)
3. docs/rules/{rule-name}.md - Documentation
4. src/index.ts updates:
   • Import statement
   • configs.recommended.rules entry
   • rules object entry
5. README.md mention

Test Requirements

• Minimum 20 tests per rule
• 10+ valid cases (code that should NOT trigger)
• 10+ invalid cases (code that SHOULD trigger)
• Edge cases from issue specification
• Auto-fix tests if rule has fixable: 'code'

Loop Prevention

The system uses MAX_LOOPS = 200 to prevent infinite loops. After 200 iterations, agents complete even if checks fail.

GitHub Secrets Required

Common Issues

Agent Stuck in Loop

If an agent keeps failing the same check:

• Check the error output in the agent conversation
• The agent will auto-stop after MAX_LOOPS iterations
• Review the failing validation and fix manually if needed

Research Workflow Not Triggering

• Ensure issue has claude-research label
• Check if research comment already exists (short-circuit logic)
• Verify CURSOR_API_KEY secret is configured

Implementation Workflow Not Triggering

• Requires all three labels: rule-request, research-complete, claude-implement
• Research workflow auto-adds claude-implement only on NO MATCH
• For MATCH cases, human must decide to proceed

Structure Validation Failing

Common mistakes:

1. Missing import in src/index.ts
2. Missing entry in configs.recommended.rules
3. Missing entry in rules object
4. Documentation not created
5. README not updated

Development Tips

Running Hooks Locally

# Test stop hook
echo '{"session_id":"test","hook_event_name":"Stop","stop_hook_active":false,"transcript_path":"/tmp/x.jsonl","permission_mode":"default"}' \
  | npx tsx scripts/claude-hooks/agent-check.ts

# Test lint-diff
npx tsx scripts/claude-hooks/lint-diff.ts --conversation-id "test"

# Test validate-rule-structure
node -e "const {validateRuleStructure} = require('./scripts/claude-hooks/validate-rule-structure'); console.log(validateRuleStructure('my-rule-name'));"

Debugging Change Log

# View current change log
cat .claude/tmp/hooks/agent-change-log.json | jq .

# Clear change log (for testing)
rm .claude/tmp/hooks/agent-change-log.json

Verifying Script Execution

# Ensure shell scripts are executable
chmod +x .claude/hooks/*.sh

# Test shell script directly
echo '{"session_id":"test","hook_event_name":"Stop","stop_hook_active":false,"transcript_path":"/tmp/x.jsonl","permission_mode":"default","cwd":"/path/to/repo"}' \
  | .claude/hooks/stop.sh