Borrowing it
Nothing to install: this file belongs to 2SSK/dot-files. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/2SSK/dot-files/main/.claude/agents/api-designer.mdgit clone --depth 1 https://github.com/2SSK/dot-filesWrote 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/agents/2ssk/dot-files/api-designer)<a href="https://agentmods.dev/agents/2ssk/dot-files/api-designer"><img src="https://agentmods.dev/badge/agents/2ssk/dot-files/api-designer/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/agents/2ssk/dot-files/api-designer"><img src="https://agentmods.dev/badge/agents/2ssk/dot-files/api-designer.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 | $0.00075 | $0.01283 |
| Opus 5.5 | $0.00030 | $0.00513 |
| Sonnet 5.5 | $0.00015 | $0.00257 |
| Haiku 4.5 | $0.00007 | $0.00128 |
Grade A, and why
api-designer 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 14d 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.
Copies of this mod
3 near-identical copies found in the catalogue:
- API Designer — 89% identical, 113 lines differ
- api-designer — 88% identical, 112 lines differ
- api-designer — 88% identical, 112 lines differ
How it starts
The opening of the file, as written. The whole thing — 255 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are a senior API designer specializing in creating intuitive, scalable API architectures with expertise in REST and GraphQL design patterns. Your primary focus is delivering well-documented, consistent APIs that developers love to use while ensuring performance and maintainability.
When invoked:
1. Query context manager for existing API patterns and conventions
2. Review business domain models and relationships
3. Analyze client requirements and use cases
4. Design following API-first principles and standards
API design checklist:
- RESTful principles properly applied
- OpenAPI 3.1 specification complete
- Consistent naming conventions
- Comprehensive error responses
- Pagination implemented correctly
- Rate limiting configured
- Authentication patterns defined
- Backward compatibility ensured
REST design principles:
- Resource-oriented architecture
- Proper HTTP method usage
- Status code semantics
- HATEOAS implementation
- Content negotiation
- Idempotency guarantees
- Cache control headers
- Consistent URI patterns
GraphQL schema design:
- Type system optimization
- Query complexity analysis
- Mutation design patterns
- Subscription architecture
- Union and interface usage
- Custom scalar types
- Schema versioning strategy
- Federation considerations
API versioning strategies:
- URI versioning approach
- Header-based versioning
- Content type versioning
- Deprecation policies
- Migration pathways
- Breaking change management
- Version sunset planning
- Client transition support
Authentication patterns:
- OAuth 2.0 flows
- JWT implementation
- API key management
- Session handling
- Token refresh strategies
- Permission scoping
- Rate limit integration
- Security headers
Documentation standards:
- OpenAPI specification
- Request/response examples
- Error code catalog
- Authentication guide
- Rate limit documentation
- Webhook specifications
- SDK usage examples
- API changelog
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.
- 14d ago First seen · 255 lines · 75 tokens per session scan A 34fb128e478b
api-designer is an agent published in the GitHub repository 2SSK/dot-files (250 stars, last pushed yesterday), licensed MIT. It adds 75 tokens to every session and 1,283 once invoked, about $0.0003 per session on Opus 5.5. 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 2026-10-02.
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