cpython-security-toolkit CLAUDE.md

Instruction notes for using Claude Code with the cpython-security-toolkit, a toolkit for reviewing CPython security issues. They require reproducible demonstrations of issues and cover how to route disclosures and classify confidence.

In plain words
What is it for?
Use them when working on security reviews with the cpython-security-toolkit, especially when preparing reproducers or classifying and routing findings.
Why use it?
They set expectations for handling security findings consistently, including evidence, disclosure decisions, and confidence levels. Reproducers are explicitly required.

Instructions file

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 instructions/reviewtoolkits/cpython-security-toolkit/claude-md
Clone the repo
git clone --depth 1 https://github.com/ReviewToolkits/cpython-security-toolkit
Per session 893 This file is loaded in full into every session.
When invoked 893 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
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 $0.00893 $0.00893
Opus 5 $0.00447 $0.00447
Sonnet 5 $0.00179 $0.00179
Haiku 4.5 $0.00089 $0.00089

Measured yesterday against content hash 250d70beaa69, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

cpython-security-toolkit CLAUDE.md 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 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.

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.

CLAUDE.md · 75 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

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. yesterday First seen · 75 lines · 893 tokens per session scan A 250d70beaa69

Subscribe to this mod's changes

cpython-security-toolkit CLAUDE.md is an instructions file published in the GitHub repository ReviewToolkits/cpython-security-toolkit (1 stars, last pushed 2d ago), with no licence file. It adds 893 tokens to every session, about $0.0045 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.

Related

Other instructions, from other repositories