What is rei-checker-mcp CLAUDE.md?

A project instruction file for a checker that verifies whether designs or specifications follow set rules. It says decisions must not be made by an AI language model and that uncertain cases must be reported as uncertain.

Guiding development of the rei-checker-mcp project and documenting its design principles and decision process.

It gives coding agents clear rules for handling verification results, especially when the checker cannot decide reliably.

How fc0web/rei-checker-mcp configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to fc0web/rei-checker-mcp. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/fc0web/rei-checker-mcp/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/fc0web/rei-checker-mcp

Made for: Claude Code.

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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/fc0web/rei-checker-mcp/claude-md/github.svg)](https://agentmods.dev/instructions/fc0web/rei-checker-mcp/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/fc0web/rei-checker-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/fc0web/rei-checker-mcp/claude-md/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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/fc0web/rei-checker-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/fc0web/rei-checker-mcp/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 4,304 This file is loaded in full into every session.

When invoked 4,304 The same file — it is already loaded in full.

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.

Model	Per session	Once invoked
Fable 5.1	$0.04304	$0.04304
Opus 5.5	$0.01722	$0.01722
Sonnet 5.5	$0.00861	$0.00861
Haiku 4.5	$0.00430	$0.00430

Measured 1mo ago against content hash 9c0f76e74370, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

rei-checker-mcp 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 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.

CLAUDE.md · 241 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.

1mo ago Changed · +57 lines · +1,151 tokens per session 9c0f76e74370
2mo ago First seen · 184 lines · 3,153 tokens per session scan A 85f120a67a26

Subscribe to this mod's changes

rei-checker-mcp CLAUDE.md is an instructions file published in the GitHub repository fc0web/rei-checker-mcp (0 stars, last pushed 1mo ago), with no licence file. It adds 4,304 tokens to every session, about $0.0172 per session on Opus 5.5. 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.

rei-checker-mcp CLAUDE.md next to 6 instructions from other repositories
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rei-checker-mcp: Instructions file for Claude Code