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.
git clone --depth 1 https://github.com/Luxvil/ai-coding-rulesWrote 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/rules/luxvil/ai-coding-rules/74-api-design)<a href="https://agentmods.dev/rules/luxvil/ai-coding-rules/74-api-design"><img src="https://agentmods.dev/badge/rules/luxvil/ai-coding-rules/74-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/rules/luxvil/ai-coding-rules/74-api-design"><img src="https://agentmods.dev/badge/rules/luxvil/ai-coding-rules/74-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 | $0.00000 | $0.00345 |
| Opus 5.5 | $0.00000 | $0.00138 |
| Sonnet 5.5 | $0.00000 | $0.00069 |
| Haiku 4.5 | $0.00000 | $0.00034 |
Grade A, and why
74-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 1mo 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 74-api-design — 0 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.
What it actually says
API Design Rules
RESTful Conventions
- GET: Retrieve resources (idempotent)
- POST: Create resources
- PUT: Replace resources (idempotent)
- PATCH: Partial update
- DELETE: Remove resources (idempotent)
URL Design
- Use nouns for resources:
/users,/orders - Use hyphens for readability:
/order-items - Nest for relationships:
/users/:id/orders - Version your API:
/v1/users
Request/Response
// Consistent error shape
interface ApiError {
code: string; // "USER_NOT_FOUND"
message: string; // User-friendly message
details?: unknown; // Additional context
}
// Paginated response
interface PaginatedResponse<T> {
data: T[];
meta: {
total: number;
page: number;
limit: number;
};
}
Status Codes
- 200: Success
- 201: Created
- 204: No Content (DELETE)
- 400: Bad Request (validation)
- 401: Unauthorized (authn)
- 403: Forbidden (authz)
- 404: Not Found
- 422: Unprocessable Entity
- 500: Internal Server Error
Best Practices
- Validate inputs at the boundary
- Use rate limiting
- Add request IDs for tracing
- Document with OpenAPI/Swagger
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.
- 1mo ago First seen · 59 lines · 0 tokens per session scan A ab46bc58c363
74-api-design is a cursor rule published in the GitHub repository Luxvil/ai-coding-rules (3 stars, last pushed 22d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 345 tokens. A static security scan graded it A with 0 findings. It is 100% identical to 74-api-design, differing in 0 lines, and is treated as a copy.
Other cursor rules, from other repositories
exam-answer-format
Guidelines for writing exam-style answers in a practical, conversational style with definitions first followed by real-world examples.
lecture-reference-linking
Guidelines for including course materials lists and inline references when writing exam answers or documentation that references course materials.
short-answer-version
Guidelines for creating short/concise versions of detailed answers.
documentation-formatting
Guidelines for formatting markdown documentation to improve readability and scannability.
mermaid-diagrams
Guidelines for adding Mermaid diagrams to exam answers and documentation with automatic SVG generation support.
human-writing-style
Rules for writing naturally and authentically - avoid robotic AI tone in documentation, code comments, error messages, and explanations. Write like a human colleague, not a customer service bot.