Borrowing it
Nothing to install: this file belongs to septract/acl2-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.
curl -O https://raw.githubusercontent.com/septract/acl2-mcp/main/CLAUDE.mdgit clone --depth 1 https://github.com/septract/acl2-mcpWrote 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.
[](https://agentmods.dev/instructions/septract/acl2-mcp/claude-md)<a href="https://agentmods.dev/instructions/septract/acl2-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/septract/acl2-mcp/claude-md.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00986 | $0.00986 |
| Opus 5 | $0.00493 | $0.00493 |
| Sonnet 5 | $0.00197 | $0.00197 |
| Haiku 4.5 | $0.00099 | $0.00099 |
Grade A, and why
acl2-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 6d 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.
How it starts
The opening of the file, as written. The whole thing — 126 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLAUDE.md
This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
Project Overview
This is an MCP (Model Context Protocol) server that provides tools for interacting with the ACL2 theorem prover. The server enables AI assistants to work with ACL2 through 15 different tools, supporting both one-off execution and persistent sessions for incremental development.
Architecture
Core Components
- acl2_mcp/server.py: Main server implementation containing:
- Tool definitions and handlers (
list_tools(),call_tool()) - ACL2 execution functions (
run_acl2(),run_acl2_file()) - Session management (
SessionManager,ACL2Session) - Security validation functions (timeout, file path, identifiers, etc.)
- Tool definitions and handlers (
Execution Modes
-
One-off execution (default): Each tool call creates a fresh ACL2 process
- Code written to temp
.lispfile - ACL2 process started with code as input
- Output captured and returned
- Resources cleaned up
- Code written to temp
-
Persistent sessions: Long-running ACL2 processes for incremental work
- Managed by
SessionManager(singleton:session_manager) - Each session has stdin/stdout pipes for bidirectional communication
- Sessions maintain ACL2 world state across commands
- Auto-cleanup after 30 minutes inactivity
- Max 50 concurrent sessions
- Managed by
Session Communication
Sessions use a marker-based protocol to detect command completion:
- Commands sent via stdin
- Cryptographically random marker sent after each command:
___MARKER_{uuid}_{uuid}___ - Reads stdout until marker appears or timeout
- True total timeout (not per-line) prevents DoS
Security Features
Security validation is extensive (see SECURITY.md):
- Input validation: code length (1MB max), timeout (1-300s), file paths, identifiers
- Path traversal prevention: all paths resolved to absolute
- Command injection prevention: ACL2 strings escaped, identifiers validated
- DoS prevention: session limits, timeout enforcement, checkpoint limits
- No internal error details leaked to clients
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.
- 6d ago First seen · 126 lines · 986 tokens per session scan A 89f314fc0a43
acl2-mcp CLAUDE.md is an instructions file published in the GitHub repository septract/acl2-mcp (5 stars, last pushed 11mo ago), licensed BSD-3-Clause. It adds 986 tokens to every session, about $0.0049 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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