Borrowing it
Nothing to install: this file belongs to MDGrey33/claude_mind. 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/MDGrey33/claude_mind/main/.claude/skills/api-design/SKILL.mdgit clone --depth 1 https://github.com/MDGrey33/claude_mindWrote 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/mdgrey33/claude_mind/api-design)<a href="https://agentmods.dev/skills/mdgrey33/claude_mind/api-design"><img src="https://agentmods.dev/badge/skills/mdgrey33/claude_mind/api-design/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/mdgrey33/claude_mind/api-design"><img src="https://agentmods.dev/badge/skills/mdgrey33/claude_mind/api-design.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 | $0.00019 | $0.00789 |
| Opus 5.5 | $0.00008 | $0.00316 |
| Sonnet 5.5 | $0.00004 | $0.00158 |
| Haiku 4.5 | $0.00002 | $0.00079 |
Grade A, and why
api-design 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 2mo 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 — 151 lines — stays where its author put it; the contents beside it link to each section on GitHub.
API Design Skill
Design clean, consistent, and developer-friendly APIs.
When to Use
- Designing new API endpoints
- Refactoring existing APIs
- Creating API documentation
- Reviewing API contracts
- Planning API versioning
RESTful Principles
- Resource-based URLs -
/users,/orders - HTTP methods for actions - GET, POST, PUT, DELETE
- Stateless - No server-side sessions
- Consistent responses - Same format everywhere
- Proper status codes - 2xx, 4xx, 5xx
URL Patterns
GET /api/v1/users # List users
POST /api/v1/users # Create user
GET /api/v1/users/:id # Get user
PUT /api/v1/users/:id # Update user
DELETE /api/v1/users/:id # Delete user
GET /api/v1/users/:id/orders # Nested resource
Response Format
Success Response
{
"data": { ... },
"meta": {
"timestamp": "2025-01-01T00:00:00Z"
}
}
List Response (with pagination)
{
"data": [ ... ],
"meta": {
"page": 1,
"per_page": 20,
"total": 100,
"total_pages": 5
}
}
Error Response
{
"error": {
"code": "VALIDATION_ERROR",
"message": "Validation failed",
"details": [
{ "field": "email", "message": "Invalid email format" }
]
}
}
Status Codes
| Code | Use Case |
|---|---|
| 200 | Success |
| 201 | Created |
| 204 | No Content (DELETE) |
| 400 | Bad Request (validation) |
| 401 | Unauthorized |
| 403 | Forbidden |
| 404 | Not Found |
| 409 | Conflict |
| 429 | Rate Limited |
| 500 | Internal Error |
Pagination
Always paginate list endpoints:
GET /api/v1/users?page=1&per_page=20
GET /api/v1/users?cursor=abc123&limit=20
Filtering & Sorting
GET /api/v1/users?status=active
GET /api/v1/users?sort=created_at&order=desc
GET /api/v1/users?search=john
Rate Limiting
Include headers:
X-RateLimit-Limit: 100
X-RateLimit-Remaining: 95
X-RateLimit-Reset: 1609459200
Versioning
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.
- 2mo ago First seen · 151 lines · 19 tokens per session scan A a366cf882146
api-design is a skill published in the GitHub repository MDGrey33/claude_mind (2 stars, last pushed 10mo ago), licensed MIT. It adds 19 tokens to every session and 789 once invoked, about $0.0001 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 2026-08-31.
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