skills-auto-activation

name	skills-auto-activation
description	Use when skills aren't activating reliably - covers official solutions (better descriptions) and custom hook system for deterministic skill activation

<skill_overview> Skills often don't activate despite keywords; make activation reliable through better descriptions, explicit triggers, or custom hooks. </skill_overview>

<rigidity_level> HIGH FREEDOM - Choose solution level based on project needs (Level 1 for simple, Level 3 for complex). Hook implementation is flexible pattern, not rigid process. </rigidity_level>

<quick_reference>

Level	Solution	Effort	Reliability	When to Use
1	Better descriptions + explicit requests	Low	Moderate	Small projects, starting out
2	CLAUDE.md references	Low	Moderate	Document patterns
3	Custom hook system	High	Very High	Large projects, established patterns

XPowers includes: Auto-activation hook at hooks/user-prompt-submit/10-skill-activator.js </quick_reference>

<when_to_use> Use this skill when:

• Skills you created aren't being used automatically
• Need consistent skill activation across sessions
• Large codebases with established patterns
• Manual "/use skill-name" gets tedious

Prerequisites:

• Skills properly configured (name, description, SKILL.md)
• Code execution enabled (Settings > Capabilities)
• Skills toggled on (Settings > Capabilities) </when_to_use>

<the_problem>

What Users Experience

Symptoms:

• Keywords from skill descriptions present → skill not used
• Working on files that should trigger skills → nothing
• Skills exist but sit unused

Community reports:

• GitHub Issue #9954: "Skills not available even if explicitly enabled"
• "Claude knows it should use skills, but it's not reliable"
• Skills activation is "not reliable yet"

Root cause: Skills rely on Claude recognizing relevance (not deterministic) </the_problem>

<solution_levels>

Level 1: Official Solutions (Start Here)

1. Improve Skill Descriptions

❌ Bad:

name: backend-dev
description: Helps with backend development

✅ Good:

name: backend-dev-guidelines
description: Use when creating API routes, controllers, services, or repositories in backend - enforces TypeScript patterns, error handling with Sentry, and Prisma repository pattern

Key elements:

• Specific keywords: "API routes", "controllers", "services"
• When to use: "Use when creating..."
• What it enforces: Patterns, error handling

2. Be Explicit in Requests

Instead of: "How do I create an endpoint?"

Try: "Use my backend-dev-guidelines skill to create an endpoint"

Result: Works, but tedious

3. Check Settings

• Settings > Capabilities > Enable code execution
• Settings > Capabilities > Toggle Skills on
• Team/Enterprise: Check org-level settings

---

Level 2: Skill References (Moderate)

Reference skills in CLAUDE.md:

## When Working on Backend

Before making changes:
1. Check `/skills/backend-dev-guidelines` for patterns
2. Follow repository pattern for database access

The backend-dev-guidelines skill contains complete examples.

Pros: No custom code Cons: Claude still might not check

---

Level 3: Custom Hook System (Advanced)

How it works:

1. UserPromptSubmit hook analyzes prompt before Claude sees it
2. Matches keywords, intent patterns, file paths
3. Injects skill activation reminder into context
4. Claude sees "🎯 USE these skills" before processing

Result: "Night and day difference" - skills consistently used

Architecture

User submits prompt
    ↓
UserPromptSubmit hook intercepts
    ↓
Analyze prompt (keywords, intent, files)
    ↓
Check skill-rules.json for matches
    ↓
Inject activation reminder
    ↓
Claude sees: "🎯 USE these skills: ..."
    ↓
Claude loads and uses relevant skills

Configuration: skill-rules.json

{
  "backend-dev-guidelines": {
    "type": "domain",
    "enforcement": "suggest",
    "priority": "high",
    "promptTriggers": {
      "keywords": ["backend", "controller", "service", "API", "endpoint"],
      "intentPatterns": [
        "(create|add|build).*?(route|endpoint|controller|service)",
        "(how to|pattern).*?(backend|API)"
      ]
    },
    "fileTriggers": {
      "pathPatterns": ["backend/src/**/*.ts", "server/**/*.ts"],
      "contentPatterns": ["express\\.Router", "export.*Controller"]
    }
  },
  "test-driven-development": {
    "type": "process",
    "enforcement": "suggest",
    "priority": "high",
    "promptTriggers": {
      "keywords": ["test", "TDD", "testing"],
      "intentPatterns": [
        "(write|add|create).*?(test|spec)",
        "test.*(first|before|TDD)"
      ]
    },
    "fileTriggers": {
      "pathPatterns": ["**/*.test.ts", "**/*.spec.ts"],
      "contentPatterns": ["describe\\(", "it\\(", "test\\("]
    }
  }
}

Trigger Types

1. Keyword Triggers - Simple string matching (case insensitive)
2. Intent Pattern Triggers - Regex for actions + objects
3. File Path Triggers - Glob patterns for file paths
4. Content Pattern Triggers - Regex in file content

Hook Implementation (High-Level)

#!/usr/bin/env node
// ~/.claude/hooks/user-prompt-submit/skill-activator.js

const fs = require('fs');
const path = require('path');

// Load skill rules
const rules = JSON.parse(fs.readFileSync(
  path.join(process.env.HOME, '.claude/skill-rules.json'), 'utf8'
));

// Read prompt from stdin
let promptData = '';
process.stdin.on('data', chunk => promptData += chunk);

process.stdin.on('end', () => {
    const prompt = JSON.parse(promptData);

    // Analyze prompt for skill matches
    const activatedSkills = analyzePrompt(prompt.text);

    if (activatedSkills.length > 0) {
        // Inject skill activation reminder
        const context = `
🎯 SKILL ACTIVATION CHECK

Relevant skills for this prompt:
${activatedSkills.map(s => `- **${s.skill}** (${s.priority} priority)`).join('\n')}

Check if these skills should be used before responding.
`;

        console.log(JSON.stringify({
            decision: 'approve',
            additionalContext: context
        }));
    } else {
        console.log(JSON.stringify({ decision: 'approve' }));
    }
});

function analyzePrompt(text) {
    // Match against all skill rules
    // Return list of activated skills with priorities
}

For complete working implementation: See resources/hook-implementation.md

Progressive Enhancement

Phase 1 (Week 1): Basic keyword matching

{"keywords": ["backend", "API", "controller"]}

Phase 2 (Week 2): Add intent patterns

{"intentPatterns": ["(create|add).*?(route|endpoint)"]}

Phase 3 (Week 3): Add file triggers

{"fileTriggers": {"pathPatterns": ["backend/**/*.ts"]}}

Phase 4 (Ongoing): Refine based on observation </solution_levels>

### Before Hook System

• Skills sit unused despite perfect keywords
• Manual "/use skill-name" every time
• Inconsistent patterns across codebase
• Time spent fixing "creative interpretations"

After Hook System

• Skills activate automatically and reliably
• Consistent patterns enforced
• Claude self-checks before showing code
• "Night and day difference"

Real user: "Skills went from 'expensive decorations' to actually useful"

## Hook System Limitations

1. Requires hook system - Not built into Claude Code
2. Maintenance overhead - skill-rules.json needs updates
3. May over-activate - Too many skills overwhelm context
4. Not perfect - Still relies on Claude using activated skills

Considerations

Token usage:

• Activation reminder adds ~50-100 tokens per prompt
• Multiple skills add more tokens
• Use priorities to limit activation

Performance:

• Hook adds ~100-300ms to prompt processing
• Acceptable for quality improvement
• Optimize regex patterns if slow

Maintenance:

• Update rules when adding new skills
• Review activation logs monthly
• Refine patterns based on misses

## Approach 1: MCP Integration

Use Model Context Protocol to provide skills as context.

Pros: Built into Claude system Cons: Still not deterministic, same activation issues

Approach 2: Custom System Prompt

Modify Claude's system prompt to always check certain skills.

Pros: Works without hooks Cons: Limited to Pro plan, can't customize per-project

Approach 3: Manual Discipline

Always explicitly request skill usage.

Pros: No setup required Cons: Tedious, easy to forget, doesn't scale

Approach 4: Skill Consolidation

Combine all guidelines into CLAUDE.md.

Pros: Always loaded Cons: Violates progressive disclosure, wastes tokens

Recommendation: Level 3 (hooks) for large projects, Level 1 for smaller projects

<critical_rules>

Rules That Have No Exceptions

1. Try Level 1 first → Better descriptions and explicit requests before building hooks
2. Observe before building → Watch which prompts should activate skills
3. Start with keywords → Add complexity incrementally (keywords → intent → files)
4. Keep hook fast (<1 second) → Don't block prompt processing
5. Maintain skill-rules.json → Update when skills change

Common Excuses

All of these mean: Try Level 1 first, then decide.

• "Skills should just work automatically" (They should, but don't reliably - workaround needed)
• "Hook system too complex" (Setup takes 2 hours, saves hundreds of hours)
• "I'll manually specify skills" (You'll forget, it gets tedious)
• "Improving descriptions will fix it" (Helps, but not deterministic)
• "This is overkill" (Maybe - start Level 1, upgrade if needed) </critical_rules>

<verification_checklist> Before building hook system:

• Tried improving skill descriptions (Level 1)
• Tried explicit skill requests (Level 1)
• Checked all settings are enabled
• Observed which prompts should activate skills
• Identified patterns in failures
• Project large enough to justify hook overhead
• Have time for 2-hour setup + ongoing maintenance

If Level 1 works: Don't build hook system

If Level 1 insufficient: Build hook system (Level 3) </verification_checklist>

**This skill covers:** Skill activation strategies

Related skills:

• /skill:building-hooks (how to build hook system)
• /skill:using-hyper (when to use skills generally)
• /skill:writing-skills (creating skills that activate well)

This skill enables:

• Consistent enforcement of patterns
• Automatic guideline checking
• Reliable skill usage across sessions

XPowers includes: Auto-activation hook at hooks/user-prompt-submit/10-skill-activator.js

**Detailed implementation:** - [Complete working hook code](resources/hook-implementation.md) - [skill-rules.json examples](resources/skill-rules-examples.md) - [Troubleshooting guide](resources/troubleshooting.md)

Official documentation:

• Anthropic Skills Best Practices
• Claude Code Hooks Guide

When stuck:

• Skills still not activating → Check Settings > Capabilities
• Hook not working → Check ~/.claude/logs/hooks.log
• Over-activation → Reduce keywords, increase priority thresholds
• Under-activation → Add more keywords, broaden intent patterns