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.
npx agentmods add skills/mindmuxai/brain.md/brain-setupnpx skills add mindmuxai/brain.md --skill brain-setupgit clone --depth 1 https://github.com/mindmuxai/brain.mdWhat 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 | $0.00060 | $0.02278 |
| Opus 5 | $0.00030 | $0.01139 |
| Sonnet 5 | $0.00012 | $0.00456 |
| Haiku 4.5 | $0.00006 | $0.00228 |
Grade B, and why
brain-setup 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 3d 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.
Reads agent configuration directoriesmediumAgent snooping
.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.
Offer a project-local SessionStart hook so Claude Code sessions start with a compact `brain list-pages` snapshot. **Never** write `~/.claude/settings.json` — a global hook would fire in projects that have no brain. Do ** How it starts
The opening of the file, as written. The whole thing — 110 lines — stays where its author put it; the contents beside it link to each section on GitHub.
brain-setup
This skill bootstraps a project into the Open Project Brain Standard: it drops in the protocol entry point and the brain/ skeleton so the brain-page and brain-ingest skills (and the brain CLI) have something to work with. It is idempotent — safe to run again on an already-initialized project.
Preferred one-shot path: from the project root run:
node <brain-page-bundle>/bin/brain.mjs init
That command ensures BRAIN.md, scaffolds empty brain data (brainRoot-aware), and default-wires CLAUDE.md + AGENTS.md (create if missing; if present, only update/append the marked brain block — never whole-file overwrite). Use the steps below when you need the optional pre-commit hook, the optional Claude Code SessionStart hook, or are explaining the flow.
NEVER hand-edit any file under the brain directory. All reads and writes MUST go through the
brainCLI. Manual edits are unsupported and illegitimate. This scaffold creates the brain once; from then on every read and write is abrainsubcommand. There is no validator and nothing at the file layer can catch a bad manual edit, so a hand edit silently breaks the brain's invariants.
Run this from the target project's root. The skill bundle ships the templates under assets/ and the hook under hooks/; resolve <this-skill-bundle> to the directory this SKILL.md lives in.
Core invariant: there is exactly one brain, at the resolved location. The brain's data directory is location-independent — it lives at
./brainby default, but a MindMux-managed project redirects it viabrainRootin./.mindmux/preferences.json(often an absolute path to an external sidecar directory). This skill MUST resolve that location before scaffolding, and MUST NOT create a second, local./brainwhen abrainRootis set — doing so produces a split brain (an empty local skeleton shadowing the real external brain). TheBRAIN.mdprotocol document is separate: it always lives in the project root regardless of where the brain data lives.
What ships with it
11 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
- assets/BRAIN.md 17 KB
- assets/brain/architecture.md 455 B
- assets/brain/background.md 409 B
- assets/brain/flow.md 462 B
- assets/brain/index.md 89 B
- assets/brain/mindmap.md 294 B
- assets/brain/pages/.gitkeep 0 B
- assets/brain/roadmap.md 333 B
- assets/brain/stack.md 425 B
- hooks/pre-commit 1.5 KB
- hooks/session-start 1.5 KB
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.
- 3d ago First seen · 110 lines · 60 tokens per session scan B a6ae879c8e00
brain-setup is a skill published in the GitHub repository mindmuxai/brain.md (522 stars, last pushed 12d ago), licensed Apache-2.0. It adds 60 tokens to every session and 2,278 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it B with 1 finding (reads agent configuration directories). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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