Borrowing it
Nothing to install: this file belongs to brainOS-HQ/brain-os. 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/brainOS-HQ/brain-os/main/CLAUDE.mdgit clone --depth 1 https://github.com/brainOS-HQ/brain-osWrote 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/brainos-hq/brain-os/claude-md)<a href="https://agentmods.dev/instructions/brainos-hq/brain-os/claude-md"><img src="https://agentmods.dev/badge/instructions/brainos-hq/brain-os/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 | $0.00263 | $0.00263 |
| Opus 5 | $0.00131 | $0.00131 |
| Sonnet 5 | $0.00053 | $0.00053 |
| Haiku 4.5 | $0.00026 | $0.00026 |
Grade A, and why
brain-os 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.
What it actually says
CLAUDE.md
This repo is Brain OS — an MCP server for persistent operational state. State lives in .brain/.
Agent instructions
See AGENTS.md. It is the canonical, cross-tool instruction file for how to behave in this repo (MCP tool routing, output formatting, mutation safety, command vocabulary). This CLAUDE.md exists only so Claude Code finds the same rules; do not duplicate content here.
Build / dev
npm install
npm run build # tsc
npm run dev # tsc --watch
npm start # node dist/index.js (runs the MCP server)
Publish flow
- Bump
package.json+src/index.tsto the new version - Update
CHANGELOG.md npm run buildnpm publish- Verify with
npm view brain-os version
Project memory
Brain OS uses itself for state. Run /brain (Claude Code) or type brain (other tools — see AGENTS.md command vocabulary) to scan, /focus for priorities, /wrap to end a session. Project state lives in .brain/, not in this file.
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 · 29 lines · 263 tokens per session scan A 91ba7b4c3a82
brain-os CLAUDE.md is an instructions file published in the GitHub repository brainOS-HQ/brain-os (6 stars, last pushed 13d ago), licensed MIT. It adds 263 tokens to every session, about $0.0013 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.
Other instructions, from other repositories
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
codex AGENTS.md
AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, applying the notice (cutover) and fallback chain (never fail the build).
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
spec-kit AGENTS.md
AGENTS.md instructions for github/spec-kit, covering agents.md, about spec kit and specify, quickstart — add a new integration in 5 steps, integration architecture and integrationmanifest — file tracking.