fastapi-blocking-operations

fastapi-blocking-operations is a cursor rule for Cursor from paulpham157/paul-s-cursor-rules. It costs 0 tokens per session (72 once invoked), scanned A, original, MIT.

A rule set for FastAPI route files that encourages asynchronous work and limits operations that block a Python server.

In plain words
What is it for?
Use it when creating FastAPI routers, route handlers, dependencies, and database or external API operations.
Why use it?
It helps prevent slow or stuck routes when handling database work or calls to external services.

Cursor rule for Cursor

Written for Cursor: a Cursor rule (.mdc).

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 rules/paulpham157/paul-s-cursor-rules/fastapi-blocking-operations
Clone the repo
git clone --depth 1 https://github.com/paulpham157/paul-s-cursor-rules

Made for: Cursor.

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-blocking-operations

README.md
[![agentmods](https://agentmods.dev/badge/rules/paulpham157/paul-s-cursor-rules/fastapi-blocking-operations.svg)](https://agentmods.dev/rules/paulpham157/paul-s-cursor-rules/fastapi-blocking-operations)
Your own site
<a href="https://agentmods.dev/rules/paulpham157/paul-s-cursor-rules/fastapi-blocking-operations"><img src="https://agentmods.dev/badge/rules/paulpham157/paul-s-cursor-rules/fastapi-blocking-operations.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 72 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 $0.00000 $0.00072
Opus 5 $0.00000 $0.00036
Sonnet 5 $0.00000 $0.00014
Haiku 4.5 $0.00000 $0.00007

Measured 2d ago against content hash 3871b53578cd, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

fastapi-blocking-operations 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.

Origin

Copies of this mod

2 near-identical copies found in the catalogue:

1/framework_rules/rules/cursorrules-file-cursor-ai-python-fastapi-api/fastapi-blocking-operations.mdc · 8 lines

What it actually says


description: Limits blocking operations in routes, favoring asynchronous and non-blocking flows. globs: **/routers/*.py

  • Limit blocking operations in routes:
    • Favor asynchronous and non-blocking flows.
    • Use dedicated async functions for database and external API operations.
    • Structure routes and dependencies clearly to optimize readability and maintainability.
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 · 8 lines · 72 tokens per session scan A 3871b53578cd

Subscribe to this mod's changes

fastapi-blocking-operations is a cursor rule published in the GitHub repository paulpham157/paul-s-cursor-rules (27 stars, last pushed 1y ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 72 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 2026-09-03.