python

A set of rules for writing simple, readable Python code, including common style practices, type hints, and clear output. It also covers gradual implementation and basic patterns for async database work with asyncpg.

In plain words
What is it for?
Use it when building or reviewing Python features, especially FastMCP-style tools that access databases asynchronously and need readable results and clear error messages.
Why use it?
It gives a project consistent expectations for structure, naming, imports, validation, database errors, and user-facing results. This reduces unnecessary complexity and makes the code easier to maintain.

Cursor rule

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/netanelbollag/simple-psql-mcp/python
Clone the repo
git clone --depth 1 https://github.com/NetanelBollag/simple-psql-mcp
Per session 187 This file is loaded in full into every session.
When invoked 187 The same file — it is already loaded in full.
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 $0.00187 $0.00187
Opus 5 $0.00093 $0.00093
Sonnet 5 $0.00037 $0.00037
Haiku 4.5 $0.00019 $0.00019

Measured 2d ago against content hash 891a3eec4ceb, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

python 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.

rules/python.mdc · 38 lines

What it actually says

Keep it simple and readable

  • Write clear, concise code with descriptive variable names
  • Add docstrings to explain purpose of functions and classes
  • Avoid complicated patterns or over-engineering

Follow Python best practices

  • Use type hints consistently
  • Follow PEP 8 style guidelines
  • Organize imports properly (standard library first, then third-party, then local)
  • Use async/await for database operations
  • Functions should be small
  • Use helper functions to re-use code

Implement features gradually

  • Start with basic structure following FastMCP patterns
  • Keep database connections simple using asyncpg
  • Implement proper error handling for database operations
  • Add validation checks for user inputs

Make the output human-friendly

  • Format query results in an easy-to-read way
  • Provide clear error messages
  • Structure schema information logically
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 · 38 lines · 187 tokens per session scan A 891a3eec4ceb

Subscribe to this mod's changes

python is a cursor rule published in the GitHub repository NetanelBollag/simple-psql-mcp (32 stars, last pushed 1y ago), licensed MIT. It adds 187 tokens to every session, about $0.0009 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 2026-08-30.