claude-hook-advisor 0.2.1

# Hooks Guide Analysis: Implemented vs Opportunities

**Date:** November 10, 2025
**Purpose:** Compare claude-hook-advisor implementation against official Claude Code Hooks Guide

## Executive Summary

claude-hook-advisor implements **3 of 9** available hook types with a focused use case: command mapping and directory aliasing. The official hooks guide reveals **6 additional hook types** and **multiple use cases** not yet explored. This analysis identifies concrete opportunities to expand the tool's capabilities.

---

## Hook Types: Coverage Matrix

| Hook Type | Status | Current Use | Opportunity |
|-----------|--------|-------------|-------------|
| **PreToolUse** | ✅ Implemented | Command mapping/blocking | ✓ Expand to other tools beyond Bash |
| **PostToolUse** | ✅ Implemented | Basic execution tracking | ✓ Add code formatting, analytics |
| **UserPromptSubmit** | ✅ Implemented | Directory aliasing | ✓ Add learning from user feedback |
| **Notification** | ❌ Not implemented | N/A | Desktop alerts, custom notifications |
| **Stop** | ❌ Not implemented | N/A | Session cleanup, analytics export |
| **SubagentStop** | ❌ Not implemented | N/A | Subagent task tracking |
| **PreCompact** | ❌ Not implemented | N/A | Conversation history optimization |
| **SessionStart** | ❌ Not implemented | N/A | Environment validation, setup |
| **SessionEnd** | ❌ Not implemented | N/A | Statistics summary, cleanup |

**Coverage:** 3/9 hooks (33%)

---

## Use Cases: Official Guide vs Implementation

### Currently Implemented ✅

#### 1. Command Mapping (PreToolUse)
**Implementation:**
```rust
// src/hooks.rs:69-104
fn handle_pre_tool_use(config: &Config, hook_input: &HookInput, replace_mode: bool)
```
- Maps commands (npm → bun, curl → wget)
- Start-of-line regex matching prevents false positives
- Block or replace mode support
- Cached regex compilation for performance

**Alignment with Guide:** Strong - Matches "Custom permissions" use case

#### 2. Directory Aliasing (UserPromptSubmit)
**Implementation:**
```rust
// src/hooks.rs:118-141
fn handle_user_prompt_submit(config: &Config, hook_input: &HookInput)
```
- Detects semantic directory references in user prompts
- Resolves aliases to canonical paths
- Security: path canonicalization prevents traversal attacks

**Alignment with Guide:** Novel - Not explicitly mentioned in guide (innovation!)

#### 3. Execution Tracking (PostToolUse)
**Implementation:**
```rust
// src/hooks.rs:155-180
fn handle_post_tool_use(_config: &Config, hook_input: &HookInput)
```
- Basic success/failure logging
- Exit code tracking

**Alignment with Guide:** Minimal - Guide suggests richer analytics

---

### Opportunities from Hooks Guide 🎯

#### 1. **Automatic Code Formatting** (PostToolUse)
**Official Guide Example:**
> "Automatically formats TypeScript files using Prettier after file edits"

**Implementation Opportunity:**
```toml
[formatting]
"*.ts" = "prettier --write"
"*.tsx" = "prettier --write"
"*.rs" = "rustfmt"
"*.py" = "black"
"*.go" = "gofmt -w"
"*.md" = "prettier --write"
```

**Value:**
- Zero-effort code consistency
- Follows official guide's primary use case
- Integrates with existing PostToolUse handler

**Implementation Estimate:** Medium (2-3 days)
- Add `[formatting]` section to TOML config
- Detect file edits in PostToolUse via tool_name (Edit, Write, NotebookEdit)
- Execute formatter commands conditionally
- Handle formatter failures gracefully

---

#### 2. **Custom Notifications** (Notification Hook)
**Official Guide Example:**
> "Desktop alerts via notify-send when Claude awaits input"

**Implementation Opportunity:**
```toml
[notifications]
enable_desktop = true
command = "notify-send"
on_user_input_required = true
on_approval_required = true
on_error = true
```

**Value:**
- User attention when Claude needs input
- Follows official guide's notification pattern
- Works for desktop environments (Linux/macOS)

**Implementation Estimate:** Small (1-2 days)
- Add Notification hook handler
- Detect notification types from hook input
- Execute configurable notification commands
- Cross-platform support (notify-send, osascript, toast)

---

#### 3. **Session Lifecycle Management** (SessionStart/SessionEnd)
**Official Guide Coverage:**
> "SessionStart: Activates when sessions begin or resume"
> "SessionEnd: Executes when sessions terminate"

**Implementation Opportunity:**

**SessionStart:**
```toml
[session_start]
validate_environment = true
check_git_status = true
load_project_context = true
commands = [
    "git fetch --quiet",
    "echo 'Session started at $(date)'",
]
```

**SessionEnd:**
```toml
[session_end]
export_analytics = true
cleanup_temp_files = true
commands = [
    "echo 'Session ended at $(date)'",
    "echo 'Commands executed: {command_count}'",
]
```

**Value:**
- Environment validation before Claude starts
- Session statistics and cleanup
- Project context loading

**Implementation Estimate:** Medium (3-4 days)
- Add SessionStart handler for environment checks
- Add SessionEnd handler for analytics export
- Track session-level metrics (command counts, suggestions)
- Implement statistics summary formatting

---

#### 4. **Enhanced Command Logging** (PostToolUse)
**Official Guide Example:**
> "Uses jq to extract and log bash commands to a text file"

**Current Gap:** Basic console output only

**Implementation Opportunity:**
```toml
[logging]
enabled = true
log_file = "~/.claude-hook-advisor/command-history.jsonl"
include_exit_codes = true
include_timestamps = true
include_session_id = true
```

**Value:**
- Audit trail for compliance
- Debugging command issues
- Analytics for command success rates
- Follows official guide pattern

**Implementation Estimate:** Small (1-2 days)
- Add structured logging to PostToolUse
- JSONL format for easy parsing
- Optional log rotation
- Privacy controls (filter sensitive commands)

---

#### 5. **File Protection** (PreToolUse)
**Official Guide Example:**
> "Blocks edits to sensitive files like .env and .git/"

**Current Gap:** Only handles Bash commands

**Implementation Opportunity:**
```toml
[file_protection]
enabled = true
protected_paths = [
    ".env",
    ".env.*",
    ".git/**",
    "secrets/**",
    "credentials.json",
]
block_message = "This file is protected. Use --force-edit to override."
```

**Value:**
- Prevents accidental credential leaks
- Follows official guide's security pattern
- Extends PreToolUse to Edit/Write tools

**Implementation Estimate:** Medium (2-3 days)
- Extend PreToolUse to handle Edit/Write/NotebookEdit tools
- Pattern matching for protected paths
- Override mechanism for intentional edits
- Audit logging of protection violations

---

#### 6. **Markdown Code Block Enhancement** (PostToolUse)
**Official Guide Example:**
> "Python script detects programming languages in code blocks and adds appropriate tags"

**Implementation Opportunity:**
```toml
[markdown_enhancement]
enabled = true
auto_detect_language = true
add_syntax_highlighting = true
```

**Value:**
- Automatic language detection in code blocks
- Improves markdown documentation quality
- Follows official guide pattern

**Implementation Estimate:** Medium (2-3 days)
- Detect markdown file edits in PostToolUse
- Use language detection library (linguist, tree-sitter)
- Update code blocks with language tags
- Handle edge cases (already-tagged blocks)

---

#### 7. **Subagent Task Tracking** (SubagentStop)
**Official Guide Coverage:**
> "Executes when subagent tasks complete"

**Implementation Opportunity:**
```toml
[subagent_tracking]
enabled = true
log_completion = true
track_success_rate = true
notify_on_failure = true
```

**Value:**
- Track subagent effectiveness
- Debug complex multi-agent tasks
- Analytics for agent performance

**Implementation Estimate:** Medium (2-3 days)
- Add SubagentStop hook handler
- Track subagent task metadata
- Success rate analytics
- Optional notifications on failures

---

#### 8. **Pre-Compact Optimization** (PreCompact)
**Official Guide Coverage:**
> "Runs before compact operations"

**Implementation Opportunity:**
```toml
[compact_optimization]
enabled = true
preserve_important_context = true
mark_key_decisions = true
```

**Value:**
- Preserve critical context during compaction
- Optimize conversation history
- Reduce token waste

**Implementation Estimate:** Small-Medium (2-3 days)
- Add PreCompact hook handler
- Identify important context markers
- Suggest preservation strategies to Claude
- Track compaction statistics

---

## Priority Recommendations

### High Priority (Immediate Value)

1. **Automatic Code Formatting** (PostToolUse)
   - Aligns with primary guide use case
   - High user value
   - Leverages existing PostToolUse infrastructure
   - **Effort:** Medium | **Impact:** High

2. **Custom Notifications** (Notification Hook)
   - Explicit guide example
   - Improves user experience
   - Low implementation complexity
   - **Effort:** Small | **Impact:** Medium

3. **Enhanced Command Logging** (PostToolUse)
   - Explicit guide example
   - Compliance/debugging value
   - Extends existing functionality
   - **Effort:** Small | **Impact:** Medium

### Medium Priority (Workflow Enhancement)

4. **Session Lifecycle Management** (SessionStart/SessionEnd)
   - Official guide coverage
   - Professional workflow benefits
   - Foundation for analytics
   - **Effort:** Medium | **Impact:** Medium

5. **File Protection** (PreToolUse Extension)
   - Explicit guide example
   - Security value
   - Natural PreToolUse extension
   - **Effort:** Medium | **Impact:** Medium

### Lower Priority (Advanced Features)

6. **Markdown Code Block Enhancement** (PostToolUse)
   - Guide example
   - Niche use case
   - Requires external dependencies
   - **Effort:** Medium | **Impact:** Low-Medium

7. **Subagent Task Tracking** (SubagentStop)
   - New hook type
   - Advanced use case
   - Less common workflow
   - **Effort:** Medium | **Impact:** Low

8. **Pre-Compact Optimization** (PreCompact)
   - Experimental/advanced
   - Unclear value proposition
   - Complex implementation
   - **Effort:** Medium | **Impact:** Low

---

## Implementation Roadmap

### Phase 1: Core Use Cases (Weeks 1-2)
- [ ] Automatic code formatting (PostToolUse)
- [ ] Custom notifications (Notification hook)
- [ ] Enhanced command logging (PostToolUse)

**Deliverable:** v0.3.0 with official guide alignment

### Phase 2: Lifecycle & Security (Weeks 3-4)
- [ ] Session lifecycle management (SessionStart/SessionEnd)
- [ ] File protection (PreToolUse extension)

**Deliverable:** v0.4.0 with professional workflow features

### Phase 3: Advanced Features (Weeks 5-6)
- [ ] Markdown enhancement (PostToolUse)
- [ ] Subagent tracking (SubagentStop)
- [ ] Pre-compact optimization (PreCompact)

**Deliverable:** v0.5.0 with full hook coverage

---

## Technical Considerations

### Architecture Impact

**Current Structure:**
```rust
pub fn run_as_hook(config_path: &str, replace_mode: bool) -> Result<()> {
    match hook_input.hook_event_name.as_str() {
        "PreToolUse" => handle_pre_tool_use(...),
        "UserPromptSubmit" => handle_user_prompt_submit(...),
        "PostToolUse" => handle_post_tool_use(...),
        _ => eprintln!("Warning: Unknown hook event type"),
    }
}
```

**Needed Additions:**
```rust
match hook_input.hook_event_name.as_str() {
    "PreToolUse" => handle_pre_tool_use(...),
    "PostToolUse" => handle_post_tool_use(...),
    "UserPromptSubmit" => handle_user_prompt_submit(...),
    "Notification" => handle_notification(...),        // NEW
    "Stop" => handle_stop(...),                        // NEW
    "SubagentStop" => handle_subagent_stop(...),       // NEW
    "PreCompact" => handle_pre_compact(...),           // NEW
    "SessionStart" => handle_session_start(...),       // NEW
    "SessionEnd" => handle_session_end(...),           // NEW
    _ => eprintln!("Warning: Unknown hook event type"),
}
```

### Configuration Schema Evolution

**Current:**
```toml
[commands]
npm = "bun"

[semantic_directories]
docs = "~/Documents/Documentation"
```

**Proposed Extensions:**
```toml
[commands]
npm = "bun"

[semantic_directories]
docs = "~/Documents/Documentation"

[formatting]
"*.rs" = "rustfmt"

[notifications]
enable_desktop = true

[logging]
log_file = "~/.claude-hook-advisor/command-history.jsonl"

[file_protection]
protected_paths = [".env", ".git/**"]

[session_start]
validate_environment = true

[session_end]
export_analytics = true

[subagent_tracking]
enabled = true

[compact_optimization]
enabled = true

[markdown_enhancement]
enabled = true
```

### Backward Compatibility

**Strategy:**
- All new sections optional (use `#[serde(default)]`)
- Existing configs continue working unchanged
- Feature flags for gradual rollout
- Comprehensive migration guide

---

## Security Considerations

From the official guide:
> "You must consider the security implication of hooks as you add them, because hooks run automatically during the agent loop with your current environment's credentials."

**For New Features:**

1. **File Protection:**
   - Prevent credential leakage
   - Audit all protection overrides
   - Default to paranoid security

2. **Command Logging:**
   - Sanitize sensitive data (passwords, tokens)
   - Configurable filtering
   - Secure log file permissions (0600)

3. **Notifications:**
   - Avoid exposing sensitive content in notifications
   - User control over notification verbosity
   - Respect privacy preferences

4. **Session Lifecycle:**
   - Validate environment safely
   - No automatic credential access
   - User approval for sensitive operations

---

## Documentation Gaps

### What the Guide Covers Well:
- Hook event types and timing
- Primary use cases with examples
- Security warnings
- Configuration structure

### What the Guide Could Expand:
- Detailed JSON schema for each hook type
- Tool name enumeration (Bash, Edit, Write, etc.)
- Cross-platform considerations
- Performance best practices
- Error handling patterns

### Opportunities for claude-hook-advisor Docs:
- Become reference implementation
- Provide comprehensive examples
- Document hook interaction patterns
- Share performance benchmarks

---

## Competitive Analysis

**Similar Tools:**
- Shell aliases (static, no AI integration)
- Git hooks (narrow scope)
- Package manager configs (tool-specific)

**claude-hook-advisor Advantages:**
- Dynamic, AI-aware command mapping
- Multi-hook integration
- Natural language directory references
- Extensible architecture

**Differentiation Opportunities:**
1. **Only tool with full 9-hook coverage** (after implementation)
2. **Reference implementation** for Claude Code hooks guide
3. **Comprehensive example collection** for hook patterns
4. **Production-ready** with security, performance, testing

---

## Community & Contribution

### Potential Contributions:

1. **Hook Pattern Library:**
   - Community-contributed hook configurations
   - Best practices collection
   - Domain-specific profiles (web dev, ML, DevOps)

2. **Integration Examples:**
   - CI/CD pipeline hooks
   - Team collaboration patterns
   - Security compliance templates

3. **Educational Content:**
   - Tutorial series for each hook type
   - Video demonstrations
   - Conference talks/blog posts

---

## Success Metrics

### Quantitative:
- Hook coverage: 33% → 100% (9/9 hooks)
- Use case coverage: 2 → 7 (guide-aligned features)
- GitHub stars: Track adoption
- crates.io downloads: Track usage

### Qualitative:
- User testimonials
- Feature requests (guide vs custom)
- Documentation clarity feedback
- Community contributions

---

## Conclusion

claude-hook-advisor has a **strong foundation** with 3/9 hooks implemented for a focused use case. The official hooks guide reveals **significant expansion opportunities** across 6 additional hook types and 5 primary use cases.

**Key Takeaways:**

1. **Strong Current Implementation:** Command mapping and directory aliasing are well-executed with proper security and performance considerations.

2. **Clear Roadmap:** Official guide provides explicit examples (code formatting, notifications, logging, file protection) ready for implementation.

3. **Innovation Potential:** Directory aliasing demonstrates innovation beyond the guide—continue exploring unique use cases.

4. **Strategic Position:** Could become **the reference implementation** for Claude Code hooks if expanded to full coverage.

**Recommended Next Step:** Implement **Automatic Code Formatting** (PostToolUse) as it aligns with the guide's primary use case, provides immediate user value, and leverages existing infrastructure.

---

**Generated by:** Claude Code Hooks Guide Analysis
**Repository:** https://github.com/sirmews/claude-hook-advisor
**Documentation:** https://code.claude.com/docs/en/hooks-guide.md