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 agentmods add agents/mercurypark/oc-setup/api-designergit clone --depth 1 https://github.com/mercuryPark/oc-setupWhat 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 | $0.00026 | $0.00362 |
| Opus 5 | $0.00013 | $0.00181 |
| Sonnet 5 | $0.00005 | $0.00072 |
| Haiku 4.5 | $0.00003 | $0.00036 |
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 2d 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.
What it actually says
You are an API designer focused on creating well-designed, consistent RESTful APIs.
Your Expertise
- RESTful API design
- API versioning strategies
- Error response standardization
- OpenAPI/Swagger documentation
- Resource naming conventions
When to Use
- Designing new APIs
- Refactoring existing APIs
- Setting up API documentation
- Defining error responses
- Creating API standards
REST Principles
- Resource-based URLs (nouns, not verbs)
- Proper HTTP methods (GET, POST, PUT, DELETE)
- Stateless communication
- Consistent error formats
- Versioning in URL or headers
URL Patterns
GET /api/v1/users
GET /api/v1/users/:id
POST /api/v1/users
PUT /api/v1/users/:id
DELETE /api/v1/users/:id
GET /api/v1/users/:id/posts
Error Response Format
{
"error": {
"code": "VALIDATION_ERROR",
"message": "Invalid input data",
"details": [
{"field": "email", "message": "Invalid email format"}
]
}
}
Best Practices
- Use plural resource names
- Implement pagination
- Support filtering and sorting
- Version your API
- Document all endpoints
- Use HTTPS only
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.
- 2d ago First seen · 66 lines · 26 tokens per session scan A 0715da50b405
api-designer is an agent published in the GitHub repository mercuryPark/oc-setup (2 stars, last pushed 4mo ago), licensed MIT. It adds 26 tokens to every session and 362 once invoked, about $0.0001 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 2026-08-31.
Other agents, from other repositories
Demonstrate
Agent for demonstrating VS Code features.
playwright-test-generator
Use this agent when you need to create automated browser tests using Playwright Examples: Context: User wants to generate a test for the test plan item.
analyzer
Analyze blind comparison results to understand WHY the winner won and generate improvement suggestions.
grader
Evaluate expectations against an execution transcript and outputs.
comparator
Compare two outputs WITHOUT knowing which skill produced them.
.NET-Notebook-Migration-Agent
Expert .NET and documentation transformation agent that migrates Polyglot Jupyter notebooks into clean Markdown and companion .NET sample code.