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 skills add nimadorostkar/Claude-Skills-collection --skill api-designgit clone --depth 1 https://github.com/nimadorostkar/Claude-Skills-collectionWrote 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/nimadorostkar/claude-skills-collection/api-design)<a href="https://agentmods.dev/skills/nimadorostkar/claude-skills-collection/api-design"><img src="https://agentmods.dev/badge/skills/nimadorostkar/claude-skills-collection/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/nimadorostkar/claude-skills-collection/api-design"><img src="https://agentmods.dev/badge/skills/nimadorostkar/claude-skills-collection/api-design.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Data Exfiltration · line 84 Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
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 | $0.00044 | $0.01049 |
| Opus 5 | $0.00022 | $0.00524 |
| Sonnet 5 | $0.00009 | $0.00210 |
| Haiku 4.5 | $0.00004 | $0.00105 |
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 11d 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 — 99 lines — stays where its author put it; the contents beside it link to each section on GitHub.
API Design
Purpose
Design HTTP APIs that clients can use correctly without reading your source code, and that you can evolve without breaking them.
When to Use
- Designing a new API or a new endpoint on an existing one.
- Reviewing an API before it becomes public and therefore permanent.
- Introducing versioning, pagination, or idempotency to an API that lacks them.
- Writing or auditing an OpenAPI specification.
Capabilities
- Resource and URL modeling.
- Status-code semantics and consistent error payloads (RFC 9457 problem details).
- Pagination strategies and their trade-offs.
- Idempotency for unsafe methods.
- Versioning and deprecation without breaking clients.
- OpenAPI specification as the source of truth.
Inputs
- The domain operations the API must expose.
- Client types: first-party, third-party, mobile, machine.
- Expected volume, page sizes, and latency requirements.
Outputs
- An OpenAPI 3.1 specification.
- Consistent error and pagination formats across every endpoint.
- A documented versioning and deprecation policy.
Workflow
- Model resources, not procedures —
POST /orders/{id}/refundsrather thanPOST /refundOrder. When an operation genuinely is not a resource, it is fine to say so, but check first. - Fix the status codes — 200 for a body, 201 with a
Locationfor creation, 202 for accepted-but-not-done, 400 for malformed, 401 versus 403 correctly, 409 for conflict, 422 for semantically invalid, 429 withRetry-After. - Standardize errors — One shape, every endpoint. RFC 9457 problem details, with a machine-readable
typeand field-level detail. - Choose pagination deliberately — Cursor-based for anything that mutates or is large. Offset only for small, static datasets.
- Make unsafe methods idempotent — Accept an
Idempotency-Keyheader on POST; return the original response on replay. - Version from day one — Even if the first version is the only one. Retrofitting a version is far worse than carrying one.
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.
- 11d ago First seen · 99 lines · 44 tokens per session scan A 4fe00c56ce3b
api-design is a skill published in the GitHub repository nimadorostkar/Claude-Skills-collection (26 stars, last pushed 23d ago), licensed MIT. It adds 44 tokens to every session and 1,049 once invoked, about $0.0002 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 2026-08-30.
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