anthropic-skill-creator

name anthropic-skill-creator description Design, review, and improve Claude/Codex skills based on Anthropic's "The Complete Guide to Building Skills for Claude". Use when creating a new skill, rewriting SKILL.md frontmatter and workflows, fixing under-triggering or over-triggering, designing scripts/references/assets, building test cases, or preparing a skill for upload/distribution. Create Skills Build skills that trigger correctly, execute reliably, and stay concise. Core Principles Use progressive disclosure: Frontmatter ( name , description ) for trigger selection. SKILL.md body for core workflow. references/ for deep details loaded only when needed. Keep skills composable: avoid assumptions that this is the only active skill. Prefer deterministic scripts for fragile validation logic. Workflow Define 2-3 concrete use cases. Draft trigger-strong frontmatter. Design reusable resources ( scripts/ , references/ , assets/ ). Write actionable instructions and error handling. Run triggering/functional/performance tests. Iterate based on under-trigger/over-trigger signals. 1) Define Use Cases Capture for each use case: User phrasing (what they actually say) Intended result Multi-step workflow and required tools (built-in and/or MCP) Failure points that need guardrails If use cases are vague, ask targeted follow-up questions before authoring. 2) Frontmatter Design (Most Important) Write only what is needed to trigger correctly. Required fields: name : kebab-case, matches folder name description : include BOTH What the skill does When to use it (trigger phrases/context/file types) Description formula: [What it does] + [When to use it] + [Key capabilities] Good pattern: "Processes PDF legal documents for contract review. Use when users ask for clause extraction, risk flags, or redline summaries from .pdf contracts." Bad pattern: "Helps with projects." Precision controls: Add negative triggers to reduce over-triggering. Mention relevant file types when applicable. Keep wording aligned with real user phrases from use cases. 3) Resource Plan scripts/ : deterministic checks/transforms used repeatedly references/ : large docs, domain logic, variant-specific guidance assets/ : templates and artifacts used in outputs Rules: Keep SKILL.md compact; link to references/ . Avoid extra docs in skill folder ( README.md , changelog, etc.). 4) Instruction Writing Write imperative, testable steps. Include: Clear step order and dependencies Validation checkpoints Common errors with concrete fixes Example user inputs and expected outputs For critical checks, prefer scripts over prose-only checks. 5) Test Protocol Run these three test groups. A. Triggering Tests Should trigger on obvious requests Should trigger on paraphrased requests Should NOT trigger on unrelated requests Target benchmark: Trigger on ~90% of relevant prompts in a 10-20 prompt suite B. Functional Tests Validate: Correct outputs Tool/API call success Error handling paths Edge cases C. Performance Comparison Compare with vs without skill: Number of clarification turns Failed tool/API calls Token usage End-to-end completion quality 6) Iteration Rules Under-triggering signals: Skill does not load when expected Users keep manually invoking it Fix: Add clearer trigger phrases and technical terms to description . Over-triggering signals: Skill loads for unrelated requests Fix: Add negative triggers and tighten scope language. Execution issues: Inconsistent outputs, retries, user corrections Fix: Tighten instructions, add explicit validations, and script critical checks. Troubleshooting Quick Guide Upload fails with missing SKILL.md : file must be exactly SKILL.md . Invalid frontmatter: verify YAML delimiters --- and valid syntax. Invalid skill name: use lowercase kebab-case. Skill not followed: move critical instructions to top and make them concrete. Slow behavior: move long content to references/ ; reduce enabled skills. Packaging Validate and package before distribution: # Scaffold a new skill directory bash scripts/new_skill.sh <skill-name> quick_validate.py and package_skill.py are not bundled in this skill. Use synapse skills show <name> to verify frontmatter, and synapse skills deploy <name> to distribute. References references/checklist.md references/prompt-templates.md references/patterns.md references/source.md : source PDF and extracted principles references/trigger-examples.md : trigger/non-trigger examples for description tuning references/failure-remedies.md : failure patterns and minimum effective fixes