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 bobmatnyc/claude-mpm-skills --skill api-design-patternsgit clone --depth 1 https://github.com/bobmatnyc/claude-mpm-skillsWrote 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/bobmatnyc/claude-mpm-skills/api-design-patterns)<a href="https://agentmods.dev/skills/bobmatnyc/claude-mpm-skills/api-design-patterns"><img src="https://agentmods.dev/badge/skills/bobmatnyc/claude-mpm-skills/api-design-patterns/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/bobmatnyc/claude-mpm-skills/api-design-patterns"><img src="https://agentmods.dev/badge/skills/bobmatnyc/claude-mpm-skills/api-design-patterns.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk pass
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 | $0.00029 | $0.05863 |
| Opus 5 | $0.00015 | $0.02932 |
| Sonnet 5 | $0.00006 | $0.01173 |
| Haiku 4.5 | $0.00003 | $0.00586 |
Grade A, and why
api-design-patterns 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 5d 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.
This is a copy
100% identical to api-design-patterns — 2 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 890 lines — stays where its author put it; the contents beside it link to each section on GitHub.
API Design Patterns
Design robust, scalable APIs using proven patterns for REST, GraphQL, and gRPC with proper versioning, authentication, and error handling.
Quick Reference
API Style Selection:
- REST: Resource-based CRUD, simple clients, HTTP-native caching
- GraphQL: Client-driven queries, complex data graphs, real-time subscriptions
- gRPC: High-performance RPC, microservices, strong typing, streaming
Critical Patterns:
- Versioning: URI (
/v1/users), header (Accept: application/vnd.api+json;version=1), content negotiation - Pagination: Offset (simple), cursor (stable), keyset (performant)
- Auth: OAuth2 (delegated), JWT (stateless), API keys (service-to-service)
- Rate limiting: Token bucket, fixed window, sliding window
- Idempotency: Idempotency keys, conditional requests, safe retry
See references/ for deep dives: rest-patterns.md, graphql-patterns.md, grpc-patterns.md, versioning-strategies.md, authentication.md
Core Principles
Universal API Design Standards
Apply these principles across all API styles:
1. Consistency Over Cleverness
- Follow established conventions for your API style
- Use predictable naming patterns (snake_case or camelCase, pick one)
- Maintain consistent error response formats
- Version breaking changes, never surprise clients
2. Design for Evolution
- Plan for versioning from day one
- Use optional fields with sensible defaults
- Deprecate gracefully with sunset dates
- Document breaking vs non-breaking changes
3. Security by Default
- Require authentication unless explicitly public
- Use HTTPS/TLS for all production endpoints
- Implement rate limiting and throttling
- Validate and sanitize all inputs
- Return minimal error details to clients
4. Developer Experience First
- Provide comprehensive documentation (OpenAPI, GraphQL schema)
- Return meaningful error messages with actionable guidance
- Use standard HTTP status codes correctly
- Include request IDs for debugging
- Offer SDKs and code generators
What ships with it
6 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.
- 5d ago First seen · 890 lines · 29 tokens per session scan A 3fbacff1c2bb
api-design-patterns is a skill published in the GitHub repository bobmatnyc/claude-mpm-skills (74 stars, last pushed 1mo ago), licensed MIT. It adds 29 tokens to every session and 5,863 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to api-design-patterns, differing in 2 lines, and is treated as a copy.
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