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-pagenpx skills add mindmuxai/brain.md --skill brain-pagegit clone --depth 1 https://github.com/mindmuxai/brain.mdWrote 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/skills/mindmuxai/brain.md/brain-page)<a href="https://agentmods.dev/skills/mindmuxai/brain.md/brain-page"><img src="https://agentmods.dev/badge/skills/mindmuxai/brain.md/brain-page.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 | $0.00047 | $0.02076 |
| Opus 5 | $0.00023 | $0.01038 |
| Sonnet 5 | $0.00009 | $0.00415 |
| Haiku 4.5 | $0.00005 | $0.00208 |
Grade A, and why
brain-page 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 — 146 lines — stays where its author put it; the contents beside it link to each section on GitHub.
brain-page
This skill is the operating manual for working with a project's brain under the Open Project Brain Standard. The protocol overview lives in the project's root BRAIN.md; here we expand the category taxonomy and the exact command for every operation.
The model is simple: everything goes through the brain CLI.
- Read =
brainread subcommands (brain-dir/list-pages/read-page <id>/read-root <slug>) — location-independent, no need to know where the brain lives. - Write =
brainwrite subcommands. Every mutation (create / update / append / archive / tag / root-page rewrite / reindex) is correct-by-construction, so frontmatter can never be mis-shaped and a compiled_truth rewrite can never silently skip its timeline entry.
NEVER hand-edit any file under the brain directory. All reads and writes MUST go through the
brainCLI. Manual edits are unsupported and illegitimate. Correctness is guaranteed by construction inside the CLI — there is no validator, and nothing at the file layer can catch or undo a bad manual edit, so a hand edit silently breaks the brain's invariants. Always reach for abrainsubcommand instead of an editor.
Invoking the CLI
The CLI ships inside this skill bundle at bin/brain.mjs. It is zero-dependency Node (ESM) — run it directly:
node <this-skill-bundle>/bin/brain.mjs <subcommand> [flags]
Resolve <this-skill-bundle> to the directory this SKILL.md lives in. In the brain.md source repository itself that path is skills/brain-page/bin/brain.mjs; when the skill is installed globally it is wherever setup linked it (e.g. ~/.claude/skills/brain-page/bin/brain.mjs). Run all commands from the project root.
The CLI resolves the brain directory itself: it reads brainRoot from ./.mindmux/preferences.json when present (absolute or relative to the project root), otherwise falls back to ./brain. A missing file, broken JSON, or absent field all fall back silently. Run brain brain-dir to see the resolved directory and its source.
What ships with it
6 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.
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 · 146 lines · 47 tokens per session scan A c4c78cd61750
brain-page is a skill published in the GitHub repository mindmuxai/brain.md (531 stars, last pushed 16d ago), licensed Apache-2.0. It adds 47 tokens to every session and 2,076 once invoked, about $0.0002 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 2026-08-30.
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