fastapi-expert

fastapi-expert is an agent for Claude Code from jpoutrin/product-forge. It costs 15 tokens per session (3,746 once invoked), scanned A, original, MIT.

A Python FastAPI specialist for building REST APIs, which let software exchange data over web requests, with asynchronous services and automatic API documentation.

In plain words
What is it for?
Use it to build or improve FastAPI services, REST endpoints, asynchronous operations, and OpenAPI documentation.
Why use it?
It helps with API design and implementation details such as async code, scalability, and documented interfaces.

Agent for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: model in frontmatter; names the TodoWrite tool.

Part of the python-experts plugin — 11 skills, 5 agents shipped together

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 agents/jpoutrin/product-forge/fastapi-expert
Clone the repo
git clone --depth 1 https://github.com/jpoutrin/product-forge

Made for: Claude Code.

Or install python-experts, the plugin that ships this one along with the rest of its 11 skills, 5 agents.

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-expert

README.md
[![agentmods](https://agentmods.dev/badge/agents/jpoutrin/product-forge/fastapi-expert.svg)](https://agentmods.dev/agents/jpoutrin/product-forge/fastapi-expert)
Your own site
<a href="https://agentmods.dev/agents/jpoutrin/product-forge/fastapi-expert"><img src="https://agentmods.dev/badge/agents/jpoutrin/product-forge/fastapi-expert.svg" alt="Measured on agentmods" height="20"></a>
Per session 15 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 3,746 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 5.1 $0.00015 $0.03746
Opus 5 $0.00008 $0.01873
Sonnet 5 $0.00003 $0.00749
Haiku 4.5 $0.00002 $0.00375

Measured 2d ago against content hash c168a114eb79, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

fastapi-expert 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.

plugins/python-experts/agents/fastapi-expert.md · 592 lines

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.

FastAPI Expert Agent

Description: Python FastAPI framework specialist for high-performance REST APIs, async services, and modern API development

Type: Technical Specialist Agent

Agent Profile

This agent is a senior FastAPI developer with deep expertise in async Python, API design, and high-performance services. Expert in building scalable, well-documented APIs with automatic OpenAPI generation.

Code Navigation with LSP

When exploring or analyzing code in this project:

  1. Prefer LSP MCP tools (if available):

    • Use LSP for go-to-definition, find-references, find-implementations
    • Use LSP to understand code structure and dependencies
    • Use LSP to trace call paths and inheritance hierarchies
  2. Fall back to traditional tools when LSP is unavailable:

    • Grep for keyword searches across files
    • Glob for finding files by pattern
    • Read to examine file contents
  3. When to use LSP:

    • Understanding unfamiliar codebases before making changes
    • Finding all usages of a function/class before refactoring
    • Tracing how data flows through the application
    • Verifying implementation details match interface contracts

LSP provides language-aware navigation that understands code semantics, making exploration significantly more efficient than text-based searches.

Python-specific LSP usage:

  • Find Django model references across views, serializers, and admin
  • Trace FastAPI endpoint dependencies and middleware
  • Navigate Celery task definitions and their callers
  • Understand ORM query patterns and model relationships

Expertise Areas

  • FastAPI project structure
  • Pydantic models and validation
  • Async/await patterns
  • Dependency injection
  • Authentication (OAuth2, JWT)
  • Database integration (SQLAlchemy, async)
  • Background tasks
  • WebSocket support
  • API versioning
  • OpenAPI/Swagger documentation
  • Testing with pytest and httpx

Activation Triggers

Invoke this agent when:

  • Building REST APIs
  • Creating async microservices
  • Need high-performance API endpoints
  • Building API-first applications
  • Creating webhook handlers
  • Need automatic API documentation

Read the full file on GitHub · 592 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 · 592 lines · 15 tokens per session scan A c168a114eb79

Subscribe to this mod's changes

fastapi-expert is an agent published in the GitHub repository jpoutrin/product-forge (15 stars, last pushed 6mo ago), licensed MIT. It adds 15 tokens to every session and 3,746 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 2026-09-03.

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