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 rules/mn-lizard-team/aiyu-multi-agent/api-design-rulesgit clone --depth 1 https://github.com/MN-Lizard-Team/aiyu-multi-agentWrote 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/mn-lizard-team/aiyu-multi-agent/api-design-rules)<a href="https://agentmods.dev/rules/mn-lizard-team/aiyu-multi-agent/api-design-rules"><img src="https://agentmods.dev/badge/rules/mn-lizard-team/aiyu-multi-agent/api-design-rules.svg" alt="Measured on agentmods" 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 | $0.01150 |
| Opus 5 | $0.00000 | $0.00575 |
| Sonnet 5 | $0.00000 | $0.00230 |
| Haiku 4.5 | $0.00000 | $0.00115 |
Grade A, and why
api-design-rules 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 3d 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 — 187 lines — stays where its author put it; the contents beside it link to each section on GitHub.
API Design Rules — Aiyu Agent Kit
APIs are contracts. Design them to last, document them to be useful.
🔴 CRITICAL: API Fundamentals
RESTful Resource Naming
✅ GOOD ❌ BAD
GET /api/users GET /api/getUsers
POST /api/users POST /api/createUser
GET /api/users/:id GET /api/user?id=123
PUT /api/users/:id POST /api/updateUser
DELETE /api/users/:id POST /api/deleteUser
GET /api/users/:id/orders GET /api/getUserOrders?uid=123
Rules:
- Nouns, not verbs — HTTP method provides the verb
- Plural for collections —
/usersnot/user - Nested resources for relationships —
/users/:id/orders - Kebab-case for multi-word —
/user-profilesnot/userProfiles
HTTP Methods
| Method | Purpose | Idempotent | Safe |
|---|---|---|---|
| GET | Read resource | Yes | Yes |
| POST | Create resource | No | No |
| PUT | Replace resource | Yes | No |
| PATCH | Partial update | No | No |
| DELETE | Remove resource | Yes | No |
Status Codes
| Code | Meaning | Use Case |
|---|---|---|
| 200 | OK | Successful GET, PUT, PATCH |
| 201 | Created | Successful POST |
| 204 | No Content | Successful DELETE |
| 400 | Bad Request | Invalid input |
| 401 | Unauthorized | Missing/invalid auth |
| 403 | Forbidden | Insufficient permissions |
| 404 | Not Found | Resource doesn't exist |
| 409 | Conflict | Duplicate resource |
| 422 | Unprocessable Entity | Validation failure |
| 429 | Too Many Requests | Rate limit exceeded |
| 500 | Internal Error | Server failure |
🟡 HIGH: Request/Response Design
Consistent Response Format
// Success
{
"data": {
"id": "usr_123",
"email": "[email protected]",
"name": "John Doe"
},
"meta": {
"request_id": "req_abc123"
}
}
// Collection
{
"data": [...],
"meta": {
"total": 150,
"page": 1,
"per_page": 20,
"total_pages": 8
}
}
// Error
{
"error": {
"code": "VALIDATION_ERROR",
"message": "Invalid email format",
"details": [
{"field": "email", "message": "Must be a valid email address"}
]
},
"meta": {
"request_id": "req_abc123"
}
}
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.
- 3d ago First seen · 187 lines · 0 tokens per session scan A 8258cb0df463
api-design-rules is a cursor rule published in the GitHub repository MN-Lizard-Team/aiyu-multi-agent (7 stars, last pushed 3mo ago), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 1,150 tokens. 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 2026-09-03.
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