ActPlane: Instructions file for Claude Code

CLAUDE.md

ActPlane CLAUDE.md is an instructions file for Claude Code, Codex from eunomia-bpf/ActPlane. It costs 2,201 tokens per session, scanned B, original, MIT.

Repository instructions for ActPlane, an operating-system harness that applies information-flow rules to an AI agent's processes, files, and network activity. It also documents the project's development workflow and tests.

In plain words
What is it for?
It is for guiding changes to ActPlane's policy compiler, eBPF engine, Rust driver, and related build or test work.
Why use it?
It gives the coding agent project-specific rules and explains how the system enforces constraints below the tool layer.

Instructions file for Claude CodeCodex

Written for Codex and Claude Code: runs codex exec, but also the file is CLAUDE.md. Also seen: mentions CLAUDE.md; mentions Claude Code; mentions Codex.

This is eunomia-bpf/ActPlane's own configuration. It tells Claude Code and Codex how to work on ActPlane itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything ActPlane configures →

Reuse

Borrowing it

Nothing to install: this file belongs to eunomia-bpf/ActPlane. 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/eunomia-bpf/ActPlane/master/CLAUDE.md
Clone the repo
git clone --depth 1 https://github.com/eunomia-bpf/ActPlane

Made for: Claude Code, Codex.

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 ActPlane CLAUDE.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/eunomia-bpf/actplane/claude-md.svg)](https://agentmods.dev/instructions/eunomia-bpf/actplane/claude-md)
Your own site
<a href="https://agentmods.dev/instructions/eunomia-bpf/actplane/claude-md"><img src="https://agentmods.dev/badge/instructions/eunomia-bpf/actplane/claude-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 2,201 This file is loaded in full into every session.
When invoked 2,201 The same file — it is already loaded in full.
Security scan B 1 finding. Scan, not verified.
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 $0.02201 $0.02201
Opus 5 $0.01100 $0.01100
Sonnet 5 $0.00440 $0.00440
Haiku 4.5 $0.00220 $0.00220

Measured 6d ago against content hash 66a3ce917f71, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade B, and why

ActPlane CLAUDE.md scanned grade B with 1 finding 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.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

sudo bash script/e2e_examples.sh # live policy match of all 12 examples (E1–E12)
CLAUDE.md · 183 lines

How it starts

The opening of the file, as written. The whole thing — 183 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.

Overview

ActPlane is an OS-level harness for AI agents. It compiles a policy DSL to an in-kernel eBPF engine that performs labeled information-flow control across process / file / network edges and reports only rule matches — each with a human-readable reason (the corrective-feedback payload). It applies policies below the tool layer (at the syscall boundary), so constraints hold across any tool, subprocess, or direct syscall the agent uses. (The mechanism is a labeled, runtime form of information-flow control — unlike classic taint analysis, which is single-bit, usually offline, and aimed at finding vulnerabilities. Code-level identifiers still use tainttaint.h, taint_config, te_* — as the implementation name.)

The repo descends from AgentSight (an eBPF observability framework); the SSL/HTTP analyzer chain, runners, web server, and frontend were removed. What remains is the labeled information-flow engine plus a minimal Rust compiler/driver.

Agent behavioral constraints (ActPlane-applied)

When acting as an agent in this repo, do not run git branch or git worktree — the user does not want new branches or worktrees created right now. Other git operations are allowed (git commit, git add, git status, git log, git push, …). If you think a different branch is needed, ask the user instead of creating one.

git branch and git worktree are also applied below the tool layer by ActPlane itself (actplane.yaml, rule no-git-branch, kill exec "git" "branch"/kill exec "git" "worktree"): they are killed whether invoked via a tool call, bash -c, or a subprocess — a worked example of a real corpus-derived guardrail in the taint DSL.

When an operation fails with EPERM / Operation not permitted, or a tool hook injects an [ActPlane] message, treat it as authoritative kernel feedback. Read .actplane/last-violation.txt if you need the full reason, then follow the suggested path instead of retrying the same operation unchanged.

Read the full file on GitHub · 183 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. 6d ago First seen · 183 lines · 2,201 tokens per session scan B 66a3ce917f71

Subscribe to this mod's changes

ActPlane CLAUDE.md is an instructions file published in the GitHub repository eunomia-bpf/ActPlane (97 stars, last pushed yesterday), licensed MIT. It adds 2,201 tokens to every session, about $0.0110 per session on Opus 5. A static security scan graded it B with 1 finding (asks for root). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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