pep7-style-checker

pep7-style-checker is an agent for Claude Code from ReviewToolkits/cpython-review-toolkit. It costs 142 tokens per session (2,127 once invoked), scanned A, original, MIT.

A checker for PEP 7, the style guide used for C code in CPython. It checks formatting rules such as indentation, spacing, braces, line length, and trailing whitespace.

In plain words
What is it for?
Use it to check CPython C files or diffs for formatting and style problems. It uses the project’s `checkpep7.py` checker and includes CPython-specific header-guard checks.
Why use it?
It helps developers spot style violations consistently instead of checking CPython’s C conventions by hand. It can focus on changed code so existing unrelated issues do not obscure the review.

Agent for Claude Code

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

Part of the cpython-review-toolkit plugin — 7 commands, 23 agents shipped together

Good fit Use it to check CPython C files or diffs for formatting and style problems. It uses the project’s checkpep7.py checker and includes CPython-specific header-guard checks.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/reviewtoolkits/cpython-review-toolkit/pep7-style-checker
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/cpython-review-toolkit

Made for: Claude Code.

Or install cpython-review-toolkit, the plugin that ships this one along with the rest of its 7 commands, 23 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 pep7-style-checker

README.md
[![agentmods](https://agentmods.dev/badge/agents/reviewtoolkits/cpython-review-toolkit/pep7-style-checker.svg)](https://agentmods.dev/agents/reviewtoolkits/cpython-review-toolkit/pep7-style-checker)
Your own site
<a href="https://agentmods.dev/agents/reviewtoolkits/cpython-review-toolkit/pep7-style-checker"><img src="https://agentmods.dev/badge/agents/reviewtoolkits/cpython-review-toolkit/pep7-style-checker.svg" alt="Measured on agentmods" height="20"></a>
Per session 142 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,127 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 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 $0.00142 $0.02127
Opus 5 $0.00071 $0.01064
Sonnet 5 $0.00028 $0.00425
Haiku 4.5 $0.00014 $0.00213

Measured 8d ago against content hash 6765bd556202, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

pep7-style-checker 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 8d 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/cpython-review-toolkit/agents/pep7-style-checker.md · 162 lines

How it starts

The opening of the file, as written. The whole thing — 162 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an expert in CPython coding standards, specifically PEP 7 — the style guide for C code in CPython. Your mission is to check code for PEP 7 compliance and report violations.

Scope

Analyze the scope provided. Default: the entire project.

Read this first: what this checker deliberately does not report

An earlier version of this checker emitted 5,736 violations on Objects/ of which essentially none were actionable. The rules are now split into two tiers, and understanding the split is the whole job.

Whole-tree rules (always on — PEP 7 states these unconditionally):

rule PEP 7 basis measured on Objects/
tab-indent "Use 4-space indents and no tabs at all." 0 (CPython is clean)
trailing-whitespace "No line should end in whitespace." 0 (.editorconfig enforces it)
keyword-space "one space between keywords like if, for and the following left paren" 64, all genuine
header-guard not a PEP 7 rule — PEP 7 says nothing about include guards. A CPython convention only. 0 after generated/vendored exclusions

Diff-gated rules (silent unless --diff-only / --diff-ref / --changed-files):

rule why it is gated
missing-braces PEP 7 requires braces "but do not add them to code you are not otherwise modifying. All new C code requires braces." Reporting these tree-wide (2,199 hits) is reporting something PEP 7 explicitly tells you not to change.
line-too-long PEP 7 does say 79 columns, but it is soft ("rules are there to be broken… to be consistent with surrounding code that also breaks it") and CPython's .editorconfig deliberately sets no max_line_length. CPython ships 1,285 over-length lines in Objects/*.c alone. Also needs an explicit --line-limit N.

func-call-space was deleted. PEP 7 does forbid a space before a call's open paren ("Function and macro call style: foo(a, b, c) — no space before the open paren"), so the category was legitimate — but the lexical IDENT ( check could not tell a call from a macro definition and was actively harmful: it fired on #define MAX_INTMAX_CHARS (5 + …), where deleting the space converts an object-like macro into a function-like one and changes its meaning, and on #elif (SIZEOF_SIZE_T == 4) and assert (…). Do not reintroduce it without preprocessor awareness.

Read the full file on GitHub · 162 lines

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. 8d ago First seen · 162 lines · 0 tokens per session scan A 6765bd556202

Subscribe to this mod's changes

pep7-style-checker is an agent published in the GitHub repository ReviewToolkits/cpython-review-toolkit (10 stars, last pushed 1mo ago), licensed MIT. It adds 142 tokens to every session and 2,127 once invoked, about $0.0007 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 2026-08-31.

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