python-pitfall-scanner

python-pitfall-scanner is an agent for Claude Code from ReviewToolkits/code-review-toolkit. It costs 0 tokens per session (1,735 once invoked), scanned A, original, no licence file.

An agent that scans Python code for mistakes that can produce wrong results without raising an error. Python is a programming language, and these mistakes include problems with defaults, closures, exceptions, hashing, iteration, and asynchronous code.

In plain words
What is it for?
Use it to inspect Python code for common behavior pitfalls such as shared mutable defaults, loop-variable closures, and unsafe asynchronous patterns.
Why use it?
It catches subtle correctness bugs that may pass tests and run normally while quietly doing the wrong thing.

Agent for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: model in frontmatter.

Part of the code-review-toolkit plugin — 8 commands, 18 agents shipped together

Good fit Use it to inspect Python code for common behavior pitfalls such as shared mutable defaults, loop-variable closures, and unsafe asynchronous patterns.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/reviewtoolkits/code-review-toolkit/python-pitfall-scanner
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.

Clone the repo
git clone --depth 1 https://github.com/ReviewToolkits/code-review-toolkit

Made for: Claude Code.

Or install code-review-toolkit, the plugin that ships this one along with the rest of its 8 commands, 18 agents.

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 python-pitfall-scanner

README.md
[![agentmods](https://agentmods.dev/badge/agents/reviewtoolkits/code-review-toolkit/python-pitfall-scanner/github.svg)](https://agentmods.dev/agents/reviewtoolkits/code-review-toolkit/python-pitfall-scanner)
Your own site
<a href="https://agentmods.dev/agents/reviewtoolkits/code-review-toolkit/python-pitfall-scanner"><img src="https://agentmods.dev/badge/agents/reviewtoolkits/code-review-toolkit/python-pitfall-scanner/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.

agentmods 80×15 button for python-pitfall-scanner

Your own site · 80×15
<a href="https://agentmods.dev/agents/reviewtoolkits/code-review-toolkit/python-pitfall-scanner"><img src="https://agentmods.dev/badge/agents/reviewtoolkits/code-review-toolkit/python-pitfall-scanner.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,735 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin unknown 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 $0.01735
Opus 5.5 $0.00000 $0.00694
Sonnet 5.5 $0.00000 $0.00347
Haiku 4.5 $0.00000 $0.00173

Measured 1mo ago against content hash 9e4129674777, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

python-pitfall-scanner 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 1mo 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.

plugins/code-review-toolkit/agents/python-pitfall-scanner.md · 116 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

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. 1mo ago First seen · 116 lines · 0 tokens per session scan A 9e4129674777

Subscribe to this mod's changes

python-pitfall-scanner is an agent published in the GitHub repository ReviewToolkits/code-review-toolkit (6 stars, last pushed 2mo ago), with no licence file. It costs nothing until one of its globs matches a file; then it loads 1,735 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 2026-08-31.

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