fastapi-pro

fastapi-pro is an agent for Claude Code from PayRequest/claude-plugins. It costs 57 tokens per session (1,236 once invoked), scanned A, a copy of api-scaffolding-fastapi-pro, MIT.

A FastAPI development assistant for building Python web APIs, including asynchronous services, microservices, and WebSocket features. APIs are interfaces that let software exchange data; asynchronous code can handle other work while waiting for operations to finish.

In plain words
What is it for?
Use it to build FastAPI routes, validate and serialise data with Pydantic, connect databases with SQLAlchemy, add authentication or WebSockets, and manage migrations, caching, uploads, and background tasks.
Why use it?
It helps structure and optimise APIs that validate data, access databases, handle many requests, or provide live communication.

Agent for Claude Code

Written for Claude Code: a Claude Code subagent (agents/*.md). Also seen: model in frontmatter.

Good fit Use it to build FastAPI routes, validate and serialise data with Pydantic, connect databases with SQLAlchemy, add authentication or WebSockets, and manage migrations, caching, uploads, and background tasks.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/payrequest/claude-plugins/fastapi-pro
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.

Clone the repo
git clone --depth 1 https://github.com/PayRequest/claude-plugins

Made for: Claude Code.

Wrote 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.

agentmods badge for fastapi-pro

README.md
[![agentmods](https://agentmods.dev/badge/agents/payrequest/claude-plugins/fastapi-pro/github.svg)](https://agentmods.dev/agents/payrequest/claude-plugins/fastapi-pro)
Your own site
<a href="https://agentmods.dev/agents/payrequest/claude-plugins/fastapi-pro"><img src="https://agentmods.dev/badge/agents/payrequest/claude-plugins/fastapi-pro/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.

agentmods 80×15 button for fastapi-pro

Your own site · 80×15
<a href="https://agentmods.dev/agents/payrequest/claude-plugins/fastapi-pro"><img src="https://agentmods.dev/badge/agents/payrequest/claude-plugins/fastapi-pro.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 57 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,236 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 97% copy Near-identical to another mod 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 5.1 $0.00057 $0.01236
Opus 5.5 $0.00023 $0.00494
Sonnet 5.5 $0.00011 $0.00247
Haiku 4.5 $0.00006 $0.00124

Measured 1mo ago against content hash 5c4c59337af8, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

fastapi-pro 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.

Origin

This is a copy

97% identical to api-scaffolding-fastapi-pro — 20 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

agents/fastapi-pro.md · 156 lines

How it starts

The opening of the file, as written. The whole thing — 156 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a FastAPI expert specializing in high-performance, async-first API development with modern Python patterns.

Purpose

Expert FastAPI developer specializing in high-performance, async-first API development. Masters modern Python web development with FastAPI, focusing on production-ready microservices, scalable architectures, and cutting-edge async patterns.

Capabilities

Core FastAPI Expertise

  • FastAPI 0.100+ features including Annotated types and modern dependency injection
  • Async/await patterns for high-concurrency applications
  • Pydantic V2 for data validation and serialization
  • Automatic OpenAPI/Swagger documentation generation
  • WebSocket support for real-time communication
  • Background tasks with BackgroundTasks and task queues
  • File uploads and streaming responses
  • Custom middleware and request/response interceptors

Data Management & ORM

  • SQLAlchemy 2.0+ with async support (asyncpg, aiomysql)
  • Alembic for database migrations
  • Repository pattern and unit of work implementations
  • Database connection pooling and session management
  • MongoDB integration with Motor and Beanie
  • Redis for caching and session storage
  • Query optimization and N+1 query prevention
  • Transaction management and rollback strategies

API Design & Architecture

  • RESTful API design principles
  • GraphQL integration with Strawberry or Graphene
  • Microservices architecture patterns
  • API versioning strategies
  • Rate limiting and throttling
  • Circuit breaker pattern implementation
  • Event-driven architecture with message queues
  • CQRS and Event Sourcing patterns

Authentication & Security

  • OAuth2 with JWT tokens (python-jose, pyjwt)
  • Social authentication (Google, GitHub, etc.)
  • API key authentication
  • Role-based access control (RBAC)
  • Permission-based authorization
  • CORS configuration and security headers
  • Input sanitization and SQL injection prevention
  • Rate limiting per user/IP

Testing & Quality Assurance

  • pytest with pytest-asyncio for async tests
  • TestClient for integration testing
  • Factory pattern with factory_boy or Faker
  • Mock external services with pytest-mock
  • Coverage analysis with pytest-cov
  • Performance testing with Locust
  • Contract testing for microservices
  • Snapshot testing for API responses

Read the full file on GitHub · 156 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. 1mo ago First seen · 156 lines · 57 tokens per session scan A 5c4c59337af8

Subscribe to this mod's changes

fastapi-pro is an agent published in the GitHub repository PayRequest/claude-plugins (11 stars, last pushed 1y ago), licensed MIT. It adds 57 tokens to every session and 1,236 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 97% identical to api-scaffolding-fastapi-pro, differing in 20 lines, and is treated as a copy.

Related

Other agents, from other repositories

backend-engineer

Backend implementation - APIs, databases, Python, business logic, data processing, server-side work.

jpoley/flowspec · 22 tokens

python-architect

Plain Python backend implementer (backend aspect). Replaces the vanilla developer on Python projects without a recognized web framework. Handles module design, CLI tools (argparse/click/typer), data pipelines, external API clients, configuration (pydantic-settings / python-decouple), and library packaging. Do NOT use…

AratKruglik/claude-sdlc · 104 tokens

hermes

Backend specialist — FastAPI, Python, async, TDD (RED→GREEN→REFACTOR), modern Python stdlib, obsolete lib detection. Calls apollo for discovery, sends to themis.

ils15/pantheon-legacy · 44 tokens

error-handlers-integrator

Initializes REST API exception-to-HTTP mapping end-to-end. Invoke with: @error-handlers-integrator.

voro6yov/spec-driven-development · 33 tokens

python-engineer

Hands-on Python 3.12+ engineer. Ships async-first, type-safe, tested code with uv, ruff, FastAPI and Pydantic. TRIGGER WHEN: planning a new Python project, designing architecture, making tech-stack decisions, or implementing features. DO NOT TRIGGER WHEN: the task is writing tests (use testing:test-writer) or isolated…

acaprino/daodan · 87 tokens

drf-api

Django REST Framework specialist. Use PROACTIVELY to build and shape JSON APIs in Django projects — serializers, viewsets, routers, permissions, authentication, pagination, throttling, and filtering. Serializers own field validation; views own permissions.

toffyui/ccteams · 54 tokens