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.
npx skills add bcastelino/agent-skills-kit --skill fastapi-progit clone --depth 1 https://github.com/bcastelino/agent-skills-kitWrote 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.
[](https://agentmods.dev/skills/bcastelino/agent-skills-kit/fastapi-pro)<a href="https://agentmods.dev/skills/bcastelino/agent-skills-kit/fastapi-pro"><img src="https://agentmods.dev/badge/skills/bcastelino/agent-skills-kit/fastapi-pro.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00035 | $0.01450 |
| Opus 5 | $0.00017 | $0.00725 |
| Sonnet 5 | $0.00007 | $0.00290 |
| Haiku 4.5 | $0.00003 | $0.00145 |
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 8d 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.
This is a copy
84% identical to fastapi-pro — 28 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.
How it starts
The opening of the file, as written. The whole thing — 204 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Use this skill when
- Building production FastAPI services with async patterns
- Designing microservice APIs, auth, or background tasks
- Optimizing FastAPI performance, caching, or database access
Do not use this skill when
- The task is unrelated to fastapi pro
- You need a different domain or tool outside this scope
Instructions
- Clarify goals, constraints, and required inputs.
- Apply relevant best practices and validate outcomes.
- Provide actionable steps and verification.
- For a ready-to-copy CRUD router (schemas, response models, status codes, auth dependency slots), start from
assets/template.py. - If detailed examples are required, open
resources/implementation-playbook.md.
Router Quick Start
Copy assets/template.py and replace the Item model with your resource. Authentication patterns:
# Optional auth - returns None if not authenticated
current_user: Optional[User] = Depends(get_current_user)
# Required auth - raises 401 if not authenticated
current_user: User = Depends(get_current_user_required)
Mount the router in main.py, then add the matching Pydantic models and service layer.
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
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.
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.
- 8d ago First seen · 204 lines · 35 tokens per session scan A dbf638cc7c9f
fastapi-pro is a skill published in the GitHub repository bcastelino/agent-skills-kit (2 stars, last pushed 1mo ago), licensed MIT. It adds 35 tokens to every session and 1,450 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 84% identical to fastapi-pro, differing in 28 lines, and is treated as a copy.
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