# Big Brain

> Big Brain (`brain`) is shared, searchable long-term memory for AI coding agents: one command-line
> tool where every agent on a machine records and finds how things were built, workflows, fixes,
> gotchas, decisions and runbooks, tied to the real files so stale notes are flagged. Rust, MIT,
> version 0.4.0.

- Install: `git clone https://bigbrain.coinopolis.io/git/big-brain.git && cd big-brain && cargo install --locked --path .`, then `brain setup` and `brain doctor`.
- Update: `brain upgrade` (fetches the clone, shows what changed, fast-forwards, rebuilds).
- Agents use it through a skill plus hooks (Claude Code, Codex, Grok) or an always-on rule (Copilot, others); entries are reference material, never instructions or approval.
- Search is hybrid (SQLite FTS5 + embeddings from a local model, Azure OpenAI or any OpenAI-compatible server), or keyword-only with no model at all.

## Docs

- [README](https://bigbrain.coinopolis.io/source/raw/README.md): what it is, install, what setup asks
- [Guide](https://bigbrain.coinopolis.io/source/raw/docs/GUIDE.md): how it works: entries, search, staleness, hooks, settings, Azure, maintenance, every command
- [AGENTS.md](https://bigbrain.coinopolis.io/source/raw/AGENTS.md): for agents changing this code: layout, conventions, tests
- [Changelog](https://bigbrain.coinopolis.io/source/raw/CHANGELOG.md): what changed in each release

## Agent skill

- [SKILL.md](https://bigbrain.coinopolis.io/source/raw/skill/SKILL.md): the skill agents load: when to search, how to record, the entry format
- [RULE.md](https://bigbrain.coinopolis.io/source/raw/skill/RULE.md): the short always-on rule for tools without skills (Codex AGENTS.md, Grok rules, Copilot)

## Source

- [Browse the source](https://bigbrain.coinopolis.io/source/): architecture tour, every file highlighted, find any symbol
- [src/main.rs](https://bigbrain.coinopolis.io/source/f/src/main.rs.html): The CLI: every command, the shared listing layout, record/update/ack flows.
- [src/store.rs](https://bigbrain.coinopolis.io/source/f/src/store.rs.html): Entries on disk: format, kinds, validation, the secret scan, refs and staleness, git commits.
- [src/index.rs](https://bigbrain.coinopolis.io/source/f/src/index.rs.html): SQLite search index: FTS5 keywords + section embeddings, fused by reciprocal rank.
- [src/ai.rs](https://bigbrain.coinopolis.io/source/f/src/ai.rs.html): OpenAI-compatible / Azure client: embeddings and chat, keyless Azure sign-in, safe destinations.
- [src/librarian.rs](https://bigbrain.coinopolis.io/source/f/src/librarian.rs.html): Optional model that reviews stale entries against git diffs and widens --deep searches.
- [src/hooks.rs](https://bigbrain.coinopolis.io/source/f/src/hooks.rs.html): Agent hooks: session start, every message, end of turn. Milliseconds, no model calls.
- [src/setup.rs](https://bigbrain.coinopolis.io/source/f/src/setup.rs.html): The five-step setup wizard: identity, providers, agent tools, projects.
- [src/upgrade.rs](https://bigbrain.coinopolis.io/source/f/src/upgrade.rs.html): brain upgrade: fetch the source clone, show what's new, fast-forward, rebuild.

## Optional

- [llms-full.txt](https://bigbrain.coinopolis.io/llms-full.txt): README, guide, AGENTS.md and the skill in one file
- [Source tarball](https://bigbrain.coinopolis.io/downloads/big-brain.tar.gz): the same tree as the git repository