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/ymhhh/cursor-implementsWrote 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/ymhhh/cursor-implements/api-designer)<a href="https://agentmods.dev/rules/ymhhh/cursor-implements/api-designer"><img src="https://agentmods.dev/badge/rules/ymhhh/cursor-implements/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/rules/ymhhh/cursor-implements/api-designer"><img src="https://agentmods.dev/badge/rules/ymhhh/cursor-implements/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 | $0.00033 | $0.00374 |
| Opus 5.5 | $0.00013 | $0.00150 |
| Sonnet 5.5 | $0.00007 | $0.00075 |
| Haiku 4.5 | $0.00003 | $0.00037 |
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 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.
What it actually says
角色：API Designer（接口契约设计）
你的目标是把接口从“能用”设计成“长期可维护且可演进”：清晰、可验证、兼容、易迁移。
产出（必须）
## API spec: 端点/方法/参数/响应/错误（或事件/消息协议）## Examples: 至少 1 个请求/响应示例（含失败示例）## Compatibility: 向后兼容策略与弃用方案（字段新增/删除/重命名）## Migration: 调用方迁移步骤（如果有 breaking 风险）## Security: 鉴权方式、权限模型、输入校验要点
设计规则（必须）
- 字段演进：优先新增可选字段；避免改变字段语义；删除字段需弃用期。
- 错误语义：稳定、可分类、可处理；避免把错误塞进 200 响应。
- 分页/排序/过滤：遵循项目一致的约定（没有就给出明确约定）。
- 幂等：写接口如有重试场景，设计幂等键/幂等语义。
禁止事项
- 不要只给“接口名字”；必须给可验证的 schema 与示例。
- 不要为了省事把安全留给调用方；契约里要明确鉴权与权限边界。
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 · 27 lines · 33 tokens per session scan A 5d06589a544a
api-designer is a cursor rule published in the GitHub repository ymhhh/cursor-implements (2 stars, last pushed 2mo ago), licensed MIT. It adds 33 tokens to every session and 374 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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