fastapi

A Python framework for building web APIs, which are interfaces that let programs communicate over HTTP. It supports request validation, automatic API documentation, asynchronous code, reusable dependencies, and common authentication methods.

In plain words
What is it for?
Use it to build REST APIs, validate JSON requests and responses, generate interactive documentation, handle asynchronous requests, and add authentication.
Why use it?
It reduces the amount of code needed to define, validate, document, and secure API endpoints.

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/cn-big-cabbage/github-skill-distiller/fastapi
Any agent
npx skills add CN-big-cabbage/github-skill-distiller --skill fastapi
Clone the repo
git clone --depth 1 https://github.com/CN-big-cabbage/github-skill-distiller

Made for: Claude Code, Codex.

Per session 14 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,538 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 $0.00014 $0.01538
Opus 5 $0.00007 $0.00769
Sonnet 5 $0.00003 $0.00308
Haiku 4.5 $0.00001 $0.00154

Measured 2d ago against content hash b52aaf10f253, 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.

cases/fastapi/SKILL.md · 167 lines

How it starts

The opening of the file, as written. The whole thing — 167 lines — stays where its author put it; the contents beside it link to each section on GitHub.

FastAPI 高性能 Python Web API 框架

技能概述

本技能帮助开发者使用 FastAPI 构建现代化、高性能的 Web API,支持以下场景:

  • REST API 开发: 快速构建符合 OpenAPI 标准的 RESTful 接口
  • 数据验证: 基于 Pydantic 的自动请求/响应数据验证
  • 自动文档: 自动生成 Swagger UI 和 ReDoc 交互式 API 文档
  • 异步支持: 原生支持 async/await,处理高并发场景
  • 依赖注入: 强大的依赖注入系统,简化认证、数据库连接等公共逻辑
  • 安全认证: 内置 OAuth2、JWT、API Key 等认证方案

技术基础: FastAPI 构建于 Starlette(Web 框架层)和 Pydantic(数据验证层)之上,性能接近 NodeJS 和 Go。

架构概览

FastAPI 应用架构
├── app/
│   ├── main.py              # 应用入口,注册路由和中间件
│   ├── dependencies.py      # 公共依赖(认证、数据库会话等)
│   ├── models/              # Pydantic 数据模型
│   │   ├── __init__.py
│   │   └── user.py
│   ├── routers/             # 路由模块(按业务划分)
│   │   ├── __init__.py
│   │   ├── users.py
│   │   └── items.py
│   ├── crud/                # 数据库操作层
│   │   ├── __init__.py
│   │   └── user.py
│   └── core/                # 核心配置
│       ├── config.py
│       └── security.py

核心概念

概念 说明
路径操作 使用 @app.get/post/put/delete 装饰器定义 API 端点
路径参数 URL 中的变量,如 /items/{item_id}
查询参数 URL 查询字符串,如 /items?skip=0&limit=10
请求体 通过 Pydantic 模型接收 JSON 数据
依赖注入 通过 Depends() 注入可复用的依赖函数
中间件 处理每个请求/响应的通用逻辑
路由器 APIRouter 将路由按模块组织,类似 Flask Blueprint

使用流程

AI 助手将引导你完成以下步骤:

  1. 安装 FastAPI 及依赖(uvicorn、pydantic 等)
  2. 创建应用入口文件 main.py
  3. 定义 Pydantic 数据模型
  4. 编写路径操作函数(路由处理器)
  5. 配置依赖注入和中间件
  6. 启动开发服务器并验证 API 文档

关键章节导航

AI 助手能力

当你向 AI 描述需求时,AI 会:

  • 自动生成 路由处理函数和 Pydantic 数据模型
  • 自动配置 依赖注入(数据库会话、用户认证)
  • 自动搭建 项目骨架结构(models、routers、crud 分层)
  • 自动实现 JWT 认证和 OAuth2 安全方案
  • 自动集成 SQLAlchemy/SQLModel 数据库操作
  • 自动编写 测试用例(pytest + httpx)
  • 自动处理 CORS 配置和自定义中间件

核心功能

  • ✅ 基于 Python 类型提示的自动数据验证
  • ✅ 自动生成 OpenAPI/Swagger 交互式文档
  • ✅ 原生 async/await 异步支持
  • ✅ 强大的依赖注入系统
  • ✅ 内置安全认证(OAuth2、JWT、API Key、HTTP Basic)
  • ✅ 支持 WebSocket 实时通信
  • ✅ 支持 GraphQL(通过 Strawberry 集成)
  • ✅ 支持后台任务(BackgroundTasks)
  • ✅ 支持文件上传和静态文件服务
  • ✅ 支持中间件和 CORS 配置

Read the full file on GitHub · 167 lines

Files

What ships with it

4 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 · 167 lines · 14 tokens per session scan A b52aaf10f253

Subscribe to this mod's changes

fastapi is a skill published in the GitHub repository CN-big-cabbage/github-skill-distiller (4 stars, last pushed 2mo ago), licensed MIT. It adds 14 tokens to every session and 1,538 once invoked, about $0.0001 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.