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.
git clone --depth 1 https://github.com/beel-collab/presets.devWrote 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/rules/beel-collab/presets.dev/fastapi-rules)<a href="https://agentmods.dev/rules/beel-collab/presets.dev/fastapi-rules"><img src="https://agentmods.dev/badge/rules/beel-collab/presets.dev/fastapi-rules/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.
<a href="https://agentmods.dev/rules/beel-collab/presets.dev/fastapi-rules"><img src="https://agentmods.dev/badge/rules/beel-collab/presets.dev/fastapi-rules.svg" alt="Reviewed on agentmods" width="80" 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 | $0.00000 | $0.01135 |
| Opus 5.5 | $0.00000 | $0.00454 |
| Sonnet 5.5 | $0.00000 | $0.00227 |
| Haiku 4.5 | $0.00000 | $0.00113 |
Grade A, and why
fastapi-rules 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 today.
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 — 105 lines — stays where its author put it; the contents beside it link to each section on GitHub.
FastAPI Rules for Cursor: Pydantic Models, Dependencies and Async
Install
Install the native export at .cursor/rules/fastapi-rules.mdc.
Copy that export, not this catalog file. Catalog fields such as tools and author are for presets.dev.
Install one skill file per name. Cursor, GitHub Copilot, Codex, Antigravity CLI, and Devin can all read .agents/skills, so a second copy with the same name collides.
FastAPI Rules for Cursor: Pydantic Models, Dependencies and Async
File-scoped Cursor rule for FastAPI. It attaches when a matching file is in context.
Updated for FastAPI 0.162.5, Nov 2026
Do not upgrade dependencies or the framework version unless the task asks.
Project shape
Routers are split by resource. A route function is thin: it takes dependencies, calls a function that does the work, and returns a response model. Settings, the lifespan, and the database session live where the app already creates them. Do not build a new global client at import time.
Models
Every request body and every response has a Pydantic model. The response model is a subset. A field the client must not see, such as a password hash or an internal flag, is not on the response model. Do not response_model_exclude as the only protection if you can omit the field.
Validate constraints on the model: length, bounds, and enums. Do not re-check them with a pile of if statements that drift from the schema. Extra fields are ignored or rejected the way the project already configured. Do not pass dict(body) into an ORM create. Copy the fields you intend to write.
Dependencies and auth
Auth is a dependency that returns the current user or raises. A route that writes declares that dependency. Do not trust a user id in the path or body. Load the row and check the owner.
Database sessions are yielded from a dependency and closed in finally. A long-lived session stored on app.state without a scope is a bug. Lifespan replaces the old startup event in new code. Do not add @app.on_event("startup") beside a lifespan.
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.
- today First seen · 105 lines · 0 tokens per session scan A dd7dcdd364c9
fastapi-rules is a cursor rule published in the GitHub repository beel-collab/presets.dev (3 stars, last pushed yesterday), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,135 tokens. 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 2026-11-13.
fastapi-rules compared with cursor rules from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| fastapi-rulesbeel-collab/presets.dev | Cursor rule | 3 | yesterday | MIT | A | 0 | Cursor |
| python-conventionseliornl/rolemule | Cursor rule | 38 | today | MIT | A | 1,307 | Claude Code, Cursor |
| best-practicesofershap/fastapi-best-practices | Cursor rule | 1 | 8mo ago | MIT | A | 189 | Cursor |
| fastapiBilal140202/the-lord-of-the-skills | Cursor rule | 6 | 2mo ago | MIT | A | 0 | Cursor |
| backend-pythonjustinz12xd/HACKATON-TAWS | Cursor rule | 2 | 4mo ago | none | A | 0 | Cursor |
| ponytailDietrichGebert/ponytail | Cursor rule | 190k | 15d ago | MIT | A | 604 | Cursor |
| angular-20angular/angular | Cursor rule | 101k | today | MIT | A | 0 | Cursor |