generate-agent-skills

name	generate-agent-skills
description	Architects, generates, and validates Agent Skills. Enforces specification and best practices. Used any time an agent skill must be created or updated.
compatibility	python3
allowed-tools	python3 ls grep cat mkdir
metadata	{"author":"canonical/platform-engineering","version":"1.0.0"}

Agent Skill Architect Workflow

This skill guides you through creating high-quality Agent Skills following a proven 6-step process.

---

🚨 CRITICAL WORKFLOW REQUIREMENTS 🚨

Before you begin, understand these NON-NEGOTIABLE rules:

1. You MUST run scripts/scaffold_skill.py in Step 3.
   Manual file creation is PROHIBITED. The scaffolding script ensures consistency.

2. You MUST use the generated templates.
   After scaffolding, templates exist in references/. Use them as your foundation.

3. You MUST run scripts/validate_skill.py in Step 5.
   Validation catches errors before they propagate.

4. You MUST follow all 6 steps in order.
   Skipping steps leads to non-compliant or broken skills.

If you bypass scaffolding scripts, you have FAILED this workflow.

---

Step 1: Understanding the Skill

Before scaffolding, clearly understand how the skill will be used through concrete examples.

For New Skills:

Ask the user clarifying questions to understand:

• What functionality should the skill support?
• What are example queries that should trigger this skill?
• What outputs or actions should result?
• Are there existing workflows or tools to integrate?

Example questions:

• "Can you give some examples of how this skill would be used?"
• "What would a user say that should trigger this skill?"
• "What existing scripts or documentation should be included?"

For Existing Skills:

If working with an existing skill, analyze:

• Current SKILL.md structure and content
• Existing scripts, references, and assets
• What's working well vs. what needs improvement

Conclude this step when: You have a clear sense of the skill's functionality and triggering scenarios.

---

Step 2: Planning Reusable Contents

Analyze the concrete examples from Step 1 to identify what reusable resources would help.

⚠️ Critical Decision: Script vs. Checklist

Before planning scripts, ask: "Is this task primarily analysis or computation?"

Analysis tasks (reading, synthesizing, pattern recognition): → Use checklists or reference docs for LLM to follow → Examples: Repository analysis, code review, documentation synthesis

Computation tasks (math, APIs, precise transformations): → Use scripts for deterministic execution → Examples: Schema validation, API calls, file format conversion

Real example from this session:

• ❌ Initially planned analyze_repo.py script
• ✅ Corrected to analysis_checklist.md reference
• Why: Repository analysis = LLM strength (reading, pattern detection, synthesis)

See references/BEST_PRACTICES.md §6 for detailed decision flowchart.

---

Ask for each example:

1. How would I execute this task from scratch?
2. What scripts, references, or assets would make this repeatable?
3. Is this analysis (LLM) or computation (script)?

Resource Types:

scripts/ - For deterministic operations only:

• ✅ Math/computation (calculations, aggregations)
• ✅ External interactions (API calls, database queries)
• ✅ Precise transformations (file format conversion, schema validation)
• ✅ Repetitive generation (boilerplate rendering)
• ❌ Analysis tasks (use checklists instead)
• ❌ Pattern recognition (LLM excels at this)

references/ - For LLM-driven analysis and knowledge:

• ✅ Checklists for systematic analysis (e.g., repository discovery)
• ✅ Pattern libraries (e.g., positive constraint conversions)
• ✅ API documentation (endpoints, parameters)
• ✅ Domain knowledge (company policies, industry standards)
• ✅ Decision trees and workflows

assets/ - For files used in output:

• ✅ Templates (documents, slides, boilerplate code)
• ✅ Images (logos, icons, diagrams)
• ✅ Fonts (typography files)
• ✅ Seed data (sample datasets, fixtures)

Output: A list of specific files to create with correct categorization (script vs reference)

---

Step 3: Skill Scaffolding

⚠️ MANDATORY STEP - DO NOT SKIP ⚠️

You MUST execute the scaffolding script. Manual file creation is PROHIBITED.

Command:

python3 scripts/scaffold_skill.py --name <skill-name>

Options:

• Default mode: Creates SKILL.md + example files in scripts/, references/, assets/
• Simple mode: Use --simple flag for minimal structure (SKILL.md only)

The script will:

• ✅ Validate naming conventions (lowercase, hyphens, alphanumeric)
• ✅ Create skill directory in .github/skills/
• ✅ Generate SKILL.md with structuring guidance
• ✅ Create example files to demonstrate resource organization

Note: The script auto-detects .github/skills from git root. Naming must match regex: ^[a-z0-9][a-z0-9-]*[a-z0-9]$

---

✅ Verification Checkpoint

After running the scaffolding script, confirm these files exist:

ls -la .github/skills/<skill-name>/

Expected output:

• SKILL.md (with "Structuring This Skill" guidance section)
• scripts/example.py (placeholder script)
• references/example_reference.md (placeholder reference)
• assets/README.md (if using default mode)

🛑 STOP CONDITIONS:

• If SKILL.md does NOT exist → Scaffolding failed, do NOT proceed
• If you created files manually → You have violated the workflow, DELETE and re-run script
• If the script reported errors → Fix errors before proceeding to Step 4

---

Step 4: Content Generation

Populate the skill with actual content.

4.1: Implement Reusable Resources First

Start with scripts/, references/, and assets/ identified in Step 2.

For scripts:

• Replace scripts/example.py with actual implementation
• Test by running: python3 scripts/<script_name>.py
• Ensure error messages are descriptive (print to stderr)

For references:

• Replace references/example_reference.md with actual docs
• Keep SKILL.md lean - move details here
• For large files (>100 lines), add Table of Contents

For assets:

• Add actual template files, images, fonts
• Replace or delete assets/README.md
• Use descriptive filenames

Important: Delete any example files you don't need!

4.2: Write SKILL.md Content

Follow the structuring guidance embedded in the generated SKILL.md template.

Choose your structure pattern:

• Workflow-Based: Sequential processes (see references/workflows.md)
• Task-Based: Tool collections with different operations
• Reference/Guidelines: Standards, specifications, coding rules
• Capabilities-Based: Integrated systems with multiple features

Key elements:

1. Frontmatter (YAML):

   • name: Must match directory name exactly
   • description: High-entropy, keyword-rich, 3rd person
     • Include WHEN to use this skill (triggers)
     • Include WHAT the skill does (capabilities)
     • Example: "Processes PDF documents for form filling, text extraction, and merging. Use when working with PDF files or when user requests document manipulation tasks."

2. Body (Markdown):

   • Use imperative/infinitive form ("Run the script", not "You should run")
   • Reference scripts/references explicitly by path
   • Consult references/BEST_PRACTICES.md for the "Freedom Scale"
   • Consult references/output-patterns.md for output formatting

Delete the "Structuring This Skill" section when done - it's guidance only!

4.3: Design Patterns

For multi-step processes: See references/workflows.md

• Sequential workflows (step 1 → step 2 → step 3)
• Conditional workflows (if/then branching)
• Iterative workflows (refinement loops)

For consistent outputs: See references/output-patterns.md

• Strict templates (non-negotiable formats)
• Flexible guidance (adaptable structure)
• Examples-based (show don't tell)
• Validation checklists (quality requirements)

---

Step 5: Validation

⚠️ MANDATORY STEP - DO NOT SKIP ⚠️

Run the validation script to ensure specification compliance.

Command:

python3 scripts/validate_skill.py --path <path-to-skill-root>

Example:

python3 scripts/validate_skill.py --path .github/skills/diagnose-ci-failure

What it checks:

• ✅ Directory naming regex (^[a-z0-9][a-z0-9-]*[a-z0-9]$)
• ✅ SKILL.md exists
• ✅ YAML frontmatter has required fields (name, description)
• ✅ Name in YAML matches directory name
• ⚠️ Advisory: Presence of references/ and scripts/ (warnings only)

If validation fails:

• Read the error output carefully
• Fix critical violations immediately
• Warnings are informational (acceptable for simple skills)

When valid: Proceed to testing!

---

✅ Post-Validation Checklist

Before proceeding to Step 6, confirm:

Workflow Compliance:

• I RAN scripts/scaffold_skill.py (Step 3)
• I USED the generated templates from scaffolding
• I CONSULTED references/TEMPLATES.md and references/BEST_PRACTICES.md (Step 4)
• I RAN scripts/validate_skill.py (Step 5)
• Validation script reported SUCCESS (no critical errors)

Content Quality:

• YAML frontmatter includes name and description
• Description is high-entropy and keyword-rich
• No "Structuring This Skill" guidance section remains in SKILL.md
• Example files (example.py, example_reference.md) are deleted or replaced
• Scripts are in scripts/, references in references/, templates in assets/

🛑 STOP CONDITION: If you did NOT run the scaffolding script or manually created files, STOP and re-do from Step 3.

---

Step 6: Testing and Iteration

After creating the skill, test and refine based on real usage.

Testing Workflow:

1. Test with real examples from Step 1

   • Does the skill trigger on expected queries?
   • Do scripts execute without errors?
   • Is output quality acceptable?

2. Identify friction points:

   • Are instructions clear enough?
   • Are there missing scripts or references?
   • Is context loaded efficiently?

3. Iterate on improvements:

   • Update SKILL.md for clarity
   • Add missing examples or edge cases
   • Optimize script error handling
   • Split large references if needed (progressive disclosure)

4. Re-validate after changes

Common Iteration Patterns:

Problem: Skill isn't triggering when expected Solution: Enhance description with more keywords and trigger scenarios

Problem: Agent struggles with workflow steps Solution: Add decision tree or flowchart; consult references/workflows.md

Problem: Context feels bloated Solution: Move content from SKILL.md to references/; add grep hints

Problem: Scripts fail in edge cases Solution: Add error handling; print descriptive messages to stderr

Problem: Output quality inconsistent Solution: Add templates or validation checklist; see references/output-patterns.md

When to Stop Iterating:

✅ Skill triggers reliably on target queries
✅ Workflows execute without confusion
✅ Output quality meets requirements
✅ No critical errors in testing

---

Knowledge Retrieval

If questions arise during skill creation:

Specification questions (naming, structure, required files): → Read references/SPECIFICATION.md

Best practices (context economy, freedom scale, anti-patterns): → Read references/BEST_PRACTICES.md

Templates and examples (frontmatter, structure patterns): → Read references/TEMPLATES.md

Workflow design (sequential, conditional, iterative): → Read references/workflows.md

Output formatting (templates, examples, validation): → Read references/output-patterns.md

Do not hallucinate answers. Always consult the authoritative sources.