Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/j4flmao/agent-skillsnpx agentmods add skills/j4flmao/agent-skills/openapi-documentationWrote 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/j4flmao/agent-skills/openapi-documentation)<a href="https://agentmods.dev/skills/j4flmao/agent-skills/openapi-documentation"><img src="https://agentmods.dev/badge/skills/j4flmao/agent-skills/openapi-documentation/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/j4flmao/agent-skills/openapi-documentation"><img src="https://agentmods.dev/badge/skills/j4flmao/agent-skills/openapi-documentation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 7 findings, up to high
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 →
- high Tool Misuse · line 91 Tool parameters are crafted to achieve unintended or unsafe behavior. Parameter abuse can bypass intended safety checks (e.g. shell=True, --force, dangerous glob patterns).Fix: Validate all tool parameters against an allowlist. Reject dangerous parameter values (shell=True, --force, -rf /) and use safe defaults.
- medium Data Exfiltration · line 111 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.
- medium MCP Rug Pull · line 273 npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.Fix: Pin the version: npx @scope/[email protected]
- medium MCP Rug Pull · line 276 npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.Fix: Pin the version: npx @scope/[email protected]
- medium MCP Rug Pull · line 279 npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.Fix: Pin the version: npx @scope/[email protected]
- medium MCP Rug Pull · line 285 npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.Fix: Pin the version: npx @scope/[email protected]
- medium MCP Rug Pull · line 292 npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.Fix: Pin the version: npx @scope/[email protected]
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 | $0.00103 | $0.04385 |
| Opus 5.5 | $0.00041 | $0.01754 |
| Sonnet 5.5 | $0.00021 | $0.00877 |
| Haiku 4.5 | $0.00010 | $0.00439 |
Grade A, and why
backend-openapi-documentation 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.
How it starts
The opening of the file, as written. The whole thing — 592 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Backend OpenAPI Documentation
Purpose
Drive all API development with an OpenAPI 3.x spec-first workflow: spec defines the contract, code is generated from it, and the spec is versioned alongside the code. The OpenAPI spec is the single source of truth for the API contract.
Agent Protocol
Trigger
Exact user phrases: "OpenAPI", "Swagger", "API documentation", "spec-first", "API spec", "openapi.yaml", "swagger.json", "codegen", "openapi-generator", "API contract first".
Input Context
- Existing API endpoints or resource definitions.
- Chosen OpenAPI version (3.0.x or 3.1.x).
- Code generation target language.
Output Artifact
OpenAPI YAML/JSON spec snippet or full spec file. No file unless requested.
Response Format
Path: {path}
Method: {method}
OperationId: {operationId}
Tags: [{tag}]
Completion Criteria
- Every endpoint has: path, method, operationId, summary, tags.
- Every request/response has a schema.
- All schemas use $ref and are not inline.
- Error responses documented.
- Security schemes defined.
- Spec passes validation (spectral or swagger-cli).
Max Response Length
6 lines per endpoint. Unlimited for full spec.
Architecture Decision Tree
Spec-First vs Code-First
Who owns the API contract?
├── Spec-first (OpenAPI as source of truth)
│ ├── PRO: Contract before implementation, generates client/server code
│ ├── CON: Slower initial development, requires spec discipline
│ └── Use when: Public API, multiple consumers, external integrations
└── Code-first (annotations/comments generate spec)
├── PRO: Faster development, single source (code)
├── CON: Spec is afterthought, easy to forget docs
└── Use when: Internal API, single consumer, rapid prototyping
OpenAPI Version Decision
Do you need JSON Schema full compatibility?
├── Yes → OpenAPI 3.1.x (fully compatible with JSON Schema 2020-12)
│ ├── PRO: $ref anywhere, JSON Schema ecosystem
│ └── CON: Less tooling support, newer standard
└── No → OpenAPI 3.0.x (wider tool support)
├── PRO: Most tools support this (Swagger UI, codegen, Spectral)
└── CON: Limited JSON Schema compatibility
What ships with it
6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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 · 592 lines · 103 tokens per session scan A 3f4286021a3a
backend-openapi-documentation is a skill published in the GitHub repository j4flmao/agent-skills (34 stars, last pushed 11d ago), licensed MIT. It adds 103 tokens to every session and 4,385 once invoked, about $0.0004 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 2026-09-03.
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