fastapi

A Python framework for building web APIs, with tools for request validation, database access, dependencies, and login security.

In plain words
What is it for?
Use it to build REST APIs, define Pydantic data models, add dependency injection, and configure OAuth2 or JWT authentication.
Why use it?
It helps avoid piecing together common API behavior yourself and gives you documented patterns for handling inputs, errors, and authentication.

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/itechmeat/llm-code/fastapi
Any agent
npx skills add itechmeat/llm-code --skill fastapi
Clone the repo
git clone --depth 1 https://github.com/itechmeat/llm-code

Made for: Claude Code, Codex.

Per session 66 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,070 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 $0.00066 $0.02070
Opus 5 $0.00033 $0.01035
Sonnet 5 $0.00013 $0.00414
Haiku 4.5 $0.00007 $0.00207

Measured 2d ago against content hash cc9dd37f5c27, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

fastapi 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.

skills/fastapi/SKILL.md · 194 lines

How it starts

The opening of the file, as written. The whole thing — 194 lines — stays where its author put it; the contents beside it link to each section on GitHub.

FastAPI

This skill provides comprehensive guidance for building APIs with FastAPI.

Quick Navigation

Topic Reference
Getting started references/first-steps.md
Path parameters references/path-parameters.md
Query parameters references/query-parameters.md
Request body references/request-body.md
Validation references/validation.md
Body advanced references/body-advanced.md
Cookies/Headers references/cookies-headers.md
Pydantic models references/models.md
Forms/Files references/forms-files.md
Error handling references/error-handling.md
Path config references/path-config.md
Dependencies references/dependencies.md
Security references/security.md
Middleware references/middleware.md
CORS references/cors.md
Database references/sql-databases.md
Project structure references/bigger-applications.md
Background tasks references/background-tasks.md
Metadata/Docs references/metadata-docs.md
Testing references/testing.md
Advanced responses references/responses-advanced.md
WebSockets references/websockets.md
Templates references/templates.md
Settings/Env vars references/settings.md
Lifespan events references/lifespan.md
OpenAPI advanced references/openapi-advanced.md

When to Use

  • Creating REST APIs with Python
  • Adding endpoints with automatic validation
  • Implementing OAuth2/JWT authentication
  • Working with Pydantic models
  • Adding dependency injection
  • Configuring CORS, middleware
  • Uploading files, handling forms
  • Testing API endpoints

Read the full file on GitHub · 194 lines

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 · 194 lines · 66 tokens per session scan A cc9dd37f5c27

Subscribe to this mod's changes

fastapi is a skill published in the GitHub repository itechmeat/llm-code (22 stars, last pushed 1mo ago), licensed MIT. It adds 66 tokens to every session and 2,070 once invoked, about $0.0003 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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