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 hoangatg/ai-agent-toolkit --skill fastapi-progit clone --depth 1 https://github.com/hoangatg/ai-agent-toolkitWrote 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/hoangatg/ai-agent-toolkit/fastapi-pro)<a href="https://agentmods.dev/skills/hoangatg/ai-agent-toolkit/fastapi-pro"><img src="https://agentmods.dev/badge/skills/hoangatg/ai-agent-toolkit/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 | $0.00797 |
| Opus 5 | $0.00017 | $0.00398 |
| Sonnet 5 | $0.00007 | $0.00159 |
| Haiku 4.5 | $0.00003 | $0.00080 |
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 3d 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.
How it starts
The opening of the file, as written. The whole thing — 116 lines — stays where its author put it; the contents beside it link to each section on GitHub.
FastAPI Pro
Modern Python APIs — fast to write, fast to run.
1. Architecture Decisions
When to Use FastAPI
| Factor | FastAPI | Django | Flask |
|---|---|---|---|
| Performance | ✅ Async, fast | ❌ Sync by default | ❌ Sync |
| Type safety | ✅ Pydantic built-in | ⚠️ Add-on | ❌ Manual |
| Auto docs | ✅ Swagger + ReDoc | ❌ Add-on | ❌ Add-on |
| Learning curve | Low-Medium | Medium-High | Low |
| Ecosystem | Growing | Mature | Mature |
2. Project Structure
app/
├── main.py # FastAPI app, startup
├── api/
│ ├── routes/ # Route handlers
│ └── deps.py # Dependencies
├── core/
│ ├── config.py # Settings (pydantic-settings)
│ └── security.py # Auth logic
├── models/ # SQLAlchemy/DB models
├── schemas/ # Pydantic schemas
├── services/ # Business logic
└── tests/
3. Pydantic v2 Patterns
| Feature | Usage |
|---|---|
| BaseModel | Request/response schemas |
| Field validators | Custom validation logic |
| model_validator | Cross-field validation |
| Settings | Environment config with .env |
| Computed fields | Derived values |
| Strict mode | No type coercion |
4. Dependency Injection
DI Patterns
| Pattern | Use Case |
|---|---|
| Function deps | DB session, current user |
| Class deps | Configurable, stateful |
| Yield deps | Resource cleanup (DB, files) |
| Nested deps | Composition (auth → user → permissions) |
Principles
| Principle | Application |
|---|---|
| Single responsibility | One dep, one concern |
| Testable | Override deps in tests |
| Cacheable | use_cache=True for expensive |
| Async-friendly | Use async def for IO deps |
5. Async Patterns
| Pattern | When |
|---|---|
| async def | IO-bound routes (DB, HTTP calls) |
| def (sync) | CPU-bound, blocking libraries |
| Background tasks | Fire-and-forget after response |
| asyncio.gather | Parallel async operations |
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.
- 3d ago First seen · 116 lines · 35 tokens per session scan A d48ea35a576c
fastapi-pro is a skill published in the GitHub repository hoangatg/ai-agent-toolkit (1 stars, last pushed 5mo ago), licensed MIT. It adds 35 tokens to every session and 797 once invoked, about $0.0002 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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