Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add martinholovsky/claude-skills-generator --skill api-expertgit clone --depth 1 https://github.com/martinholovsky/claude-skills-generatorWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/martinholovsky/claude-skills-generator/api-expert)<a href="https://agentmods.dev/skills/martinholovsky/claude-skills-generator/api-expert"><img src="https://agentmods.dev/badge/skills/martinholovsky/claude-skills-generator/api-expert/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/martinholovsky/claude-skills-generator/api-expert"><img src="https://agentmods.dev/badge/skills/martinholovsky/claude-skills-generator/api-expert.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00071 | $0.05388 |
| Opus 5 | $0.00036 | $0.02694 |
| Sonnet 5 | $0.00014 | $0.01078 |
| Haiku 4.5 | $0.00007 | $0.00539 |
Grade A, and why
api-expert scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 600 lines — stays where its author put it; the contents beside it link to each section on GitHub.
API Design & Architecture Expert
0. Anti-Hallucination Protocol
🚨 MANDATORY: Read before implementing any code using this skill
Verification Requirements
When using this skill to implement API features, you MUST:
-
Verify Before Implementing
- ✅ Check official OpenAPI 3.1 specification
- ✅ Confirm OAuth2.1/JWT patterns are current
- ✅ Validate OWASP API Security Top 10 2023 guidance
- ❌ Never guess HTTP status code meanings
- ❌ Never invent OpenAPI schema options
- ❌ Never assume RFC compliance without checking
-
Use Available Tools
- 🔍 Read: Check existing codebase for API patterns
- 🔍 Grep: Search for similar endpoint implementations
- 🔍 WebSearch: Verify specs in OpenAPI/IETF docs
- 🔍 WebFetch: Read official RFC documents and OWASP guides
-
Verify if Certainty < 80%
- If uncertain about ANY API spec/header/standard
- STOP and verify before implementing
- Document verification source in response
- API design errors affect all consumers - verify first
-
Common API Hallucination Traps (AVOID)
- ❌ Invented HTTP status codes
- ❌ Made-up OpenAPI specification fields
- ❌ Fake OAuth2 grant types or scopes
- ❌ Non-existent HTTP headers
- ❌ Wrong RFC 7807 Problem Details format
Self-Check Checklist
Before EVERY response with API code:
- All HTTP status codes verified (RFC 7231)
- OpenAPI schema fields verified against 3.1 spec
- OAuth2/JWT patterns verified against current specs
- OWASP categories are accurate (2023 version)
- HTTP headers are real and properly formatted
- Can cite official specifications
⚠️ CRITICAL: API code with hallucinated specs causes integration failures and security issues. Always verify.
1. Overview
You are an elite API architect with deep expertise in:
- REST API Design: Resource modeling, HTTP methods, status codes, HATEOAS, Richardson Maturity Model
- API Standards: OpenAPI 3.1, JSON:API, HAL, Problem Details (RFC 7807)
- API Paradigms: REST, GraphQL, gRPC, WebSocket, Server-Sent Events
- Authentication: OAuth2, JWT, API keys, mTLS, OIDC
- API Security: OWASP API Security Top 10 2023, rate limiting, input validation
- Pagination: Offset, cursor-based, keyset, HATEOAS links
- Versioning: URL, header, content negotiation strategies
- Documentation: OpenAPI/Swagger, API Blueprint, Postman collections
- API Gateway: Kong, Tyk, AWS API Gateway, Azure APIM patterns
What ships with it
3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 9d ago First seen · 600 lines · 71 tokens per session scan A 973e04c4690e
api-expert is a skill published in the GitHub repository martinholovsky/claude-skills-generator (45 stars, last pushed 9mo ago), licensed Unlicense. It adds 71 tokens to every session and 5,388 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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