fastapi-docs

A reference guide for answering questions about FastAPI, a Python framework for building web APIs. It points to the official FastAPI documentation.

In plain words
What is it for?
Explaining or configuring routes, input validation, authentication, middleware, databases, tests, WebSockets, deployment, and automatic API documentation.
Why use it?
It reduces errors caused by relying on old knowledge or assuming FastAPI works like Flask or Django.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/cookiemonsterdev/agents-skills/fastapi-docs
Any agent
npx skills add cookieMonsterDev/agents-skills --skill fastapi-docs
Clone the repo
git clone --depth 1 https://github.com/cookieMonsterDev/agents-skills

Made for: Claude Code, Codex.

Per session 87 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,189 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00087 $0.01189
Opus 5 $0.00044 $0.00594
Sonnet 5 $0.00017 $0.00238
Haiku 4.5 $0.00009 $0.00119

Measured 2d ago against content hash 16b7c04c8ba5, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

fastapi-docs 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 2d 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.

docs-skills/fastapi-docs/SKILL.md · 104 lines

How it starts

The opening of the file, as written. The whole thing — 104 lines — stays where its author put it; the contents beside it link to each section on GitHub.

FastAPI questions are easy to answer from stale memory or Flask/Django assumptions. Use this skill to ground answers in the official FastAPI documentation and return the closest authoritative page instead of generic Python web advice.

When to Use

Use this skill when the request is about:

  • FastAPI concepts, path operations, routing, and application structure
  • Request parameters, body models, response models, and validation with Pydantic
  • Dependencies (Depends, Security), sub-dependencies, and dependency injection
  • Authentication, OAuth2, JWT, HTTP Basic, and security utilities
  • Middleware, CORS, exception handlers, and custom responses
  • Background tasks, lifespan events, WebSockets, and streaming/SSE
  • SQL databases, testing with TestClient, and deployment with Uvicorn
  • OpenAPI schema, Swagger UI, ReDoc, and API metadata
  • Advanced topics: mounts, proxies, templates, static files, and async tests

Do not use this skill for:

  • Django ORM, admin, or URLconf patterns. Use django-docs instead.
  • Flask blueprints, WSGI context, or Jinja-first apps. Use flask-docs instead.
  • Starlette internals unless the question is about FastAPI's documented Starlette integration.
  • Pydantic-only questions with no FastAPI context unless the docs page is linked from FastAPI guides.

Workflow

1. Classify the request

Decide which bucket the question belongs to before searching:

  • Getting started, installation, and first steps
  • Tutorial: parameters, bodies, validation, and responses
  • Dependencies and security
  • Middleware, CORS, and error handling
  • Databases, testing, and deployment
  • Advanced: WebSockets, lifespan, mounts, proxies, templates
  • API reference (FastAPI, APIRouter, Depends, etc.)
  • How-to recipes and migration guides

If you need a quick starting point, load references/topic-map.md and jump to the closest section.

2. Search official FastAPI docs first

  • Treat fastapi.tiangolo.com as the source of truth for FastAPI.
  • Prefer pages under https://fastapi.tiangolo.com/.
  • Search with the user's exact terms plus focused FastAPI phrases such as Depends, APIRouter, response_model, HTTPException, lifespan, or TestClient.
  • When multiple pages are plausible, compare 2-3 candidate pages and pick the one that most directly answers the user's question.
  • For Pydantic v2 migration questions, check the Pydantic v1 to v2 recipe before answering from older patterns.

Read the full file on GitHub · 104 lines

Files

What ships with it

2 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.

Changes

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.

  1. 2d ago First seen · 104 lines · 87 tokens per session scan A 16b7c04c8ba5

Subscribe to this mod's changes

fastapi-docs is a skill published in the GitHub repository cookieMonsterDev/agents-skills (4 stars, last pushed 13d ago), licensed MIT. It adds 87 tokens to every session and 1,189 once invoked, about $0.0004 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 2026-08-31.

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