python-standards

A set of Python coding rules for secscan-mcp, a server that scans code for security issues. It covers typing, formatting, filesystem paths, subprocesses, and secret redaction.

In plain words
What is it for?
Use it when adding or changing Python APIs, security-scanner adapters, filesystem scanning, or subprocess code in secscan-mcp.
Why use it?
It gives contributors consistent patterns and reduces risks such as exposed secrets, unsafe subprocesses, and failed checks.

Cursor rule for Cursor

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/openjkai/secscan_mcp/python-standards
Clone the repo
git clone --depth 1 https://github.com/openjkai/secscan_mcp

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 232 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 $0.00000 $0.00232
Opus 5 $0.00000 $0.00116
Sonnet 5 $0.00000 $0.00046
Haiku 4.5 $0.00000 $0.00023

Measured yesterday against content hash d8d5140c3bb1, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

python-standards scanned grade A with 1 finding 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 yesterday.

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.

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

proc = subprocess.run(
.cursor/rules/python-standards.mdc · 31 lines

What it actually says

Python standards

  • Python 3.11+; type-annotate all public APIs; mypy strict passes on src/
  • Line length 100; Ruff format + lint (make format, make lint)
  • Use pathlib.Path for filesystem paths; validate and resolve scan targets
  • Never log or return full secret values — redact in normalized findings
  • Engine adapters: is_installed() -> bool, run(path) -> list[Finding], parse JSON/stdout defensively
  • Subprocess: timeouts, capture stderr on failure, no shell=True
  • Prefer stdlib + existing deps (mcp, pyyaml); avoid new deps without reason
# ✅ subprocess with timeout
proc = subprocess.run(
    cmd,
    cwd=root,
    capture_output=True,
    text=True,
    timeout=timeout_s,
    check=False,
)

# ❌ never echo raw secrets
finding.code_snippet = redact_secret(raw_line)
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. yesterday First seen · 31 lines · 0 tokens per session scan A d8d5140c3bb1

Subscribe to this mod's changes

python-standards is a cursor rule published in the GitHub repository openjkai/secscan_mcp (0 stars, last pushed 1mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 232 tokens. A static security scan graded it A with 1 finding (runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.