Project Brain

project-brain

A folder structure + collaboration protocol for persistent project context across AI sessions. Use it to scaffold a brain/ folder in the user's project, resume work from an existing one, or update entries when work happens.

When to invoke this skill

Activation boundary (important): Do not activate just because a brain/ folder exists in the current directory. Casual conversation that happens to occur inside a project does not require this skill — only explicit user requests do. This is intentional: the methodology refuses to auto-monitor or auto-trigger; user judgment decides when to engage.

Core principles (always honored)

• Tiered trust on brain/ writes (v2.6, METHODOLOGY §4.1): STATUS / HANDOFF / mechanical MAP registrations — write directly after the work lands, then announce what was written in the same reply (git is the review surface; silent writes are forbidden at every tier). DECISIONS / PROJECT / structural MAP changes — always ask first.
• Judgment Division: the user decides "should we record now"; the AI decides "what specifically to record"; the user reviews. Don't push specialized judgments back to the user ("which files do you want me to update?").
• DECISIONS gentle inquiry: when something feels decided, ask "does this count as decided?" — don't assert "we decided X."
• Multi-workstream: if brain/ has multiple STATUS_<workstream>.md files, don't guess this window's workstream — ask the user.

§1 New project kick-off

When the user wants to scaffold:

1. Confirm applicability: multi-module / long-lived / cross-session work? If a one-off script — say "this might be over-engineering for this project" and let the user override.
2. Confirm single or multi-workstream: most projects are single-workstream (default). If the project has parallel independent workstreams (dev + ops + outreach kind of project), ask the user to list workstream names.
3. Run scaffold: bash "${CLAUDE_PLUGIN_ROOT}/scripts/scaffold.sh" <user-project-root> (defaults to all four AI adapters: Claude, Cursor, Copilot, AGENTS.md). Add --lang zh if the project will be documented in Chinese — gives Chinese brain/ templates + Chinese CLAUDE.md (other adapters stay English regardless, since they're consumed by AI tools, not humans).
4. Walk the user through brain/PROJECT.md on day one — fill the one-line definition + "what we explicitly DON'T do." Don't let this drift into the future.
5. Scan placeholders: grep -rn "⚠️ TODO ⚠️" <user-project>/brain/ — go through with the user. Empty fields should be intentional.
6. First DECISIONS entry: append "establishing project-brain" with rejected alternatives, so this file is used from day one.

§2 Startup (entering a project that already has brain/)

Single-workstream (only STATUS.md):

1. Read brain/MAP.md
2. Read brain/STATUS.md
3. If brain/HANDOFF.md exists, read it
4. Brief report: project recognized + current progress + last blocker

Multi-workstream (multiple STATUS_<workstream>.md):

1. Read shared files: brain/MAP.md + brain/PROJECT.md
2. Don't guess — ask: "I see this is a multi-workstream project with [list workstreams]. Which one does this window work on?"
3. After the user answers, read corresponding brain/STATUS_<workstream>.md + brain/HANDOFF_<workstream>.md
4. Brief report

Universal discipline: if cwd switches to another project mid-session, re-read the new project's files; if the user switches workstreams in the same window, re-read the new workstream's files. Don't carry over memory.

§3 Handoff (user signaling window switch)

When the user says they're switching windows / context is getting full / heading out:

1. Archive the existing HANDOFF first (if one exists):

   git mv brain/HANDOFF.md brain/handoffs/$(date +%Y-%m-%d-%H%M).md
   

   (For multi-workstream: brain/HANDOFF_<current>.md → brain/handoffs/<current>/....)
2. Write a fresh brain/HANDOFF.md capturing:
   • Why the window-switch (context limit / break / refocus)
   • Current state at this exact moment
   • Where the next session should pick up
   • Things still in head not yet written down — the unique value of HANDOFF (hunches, half-tried approaches, weird debugging observations)
3. Keep it short. If STATUS was just overwritten, HANDOFF can be near-empty.

§4 Update workflow

When the user says "update the project brain":

1. Look back at what happened in this session
2. Propose a list with reasons — for each candidate file, say what to write and why:

   - STATUS overwrite: now at [X], next [Y]. Reason: you said "that's it"
   - DECISIONS: about to append? Reason: that section felt like it landed — does this count as decided?
   - MAP §5 register: new file at brain/topics/systems/[X].md. Reason: doc we just wrote
   - HANDOFF: not needed — you didn't say switch windows
   

3. Wait for user's approval per item — they may say "OK, all of them" / "skip DECISIONS, that's still discussion" / "today, just STATUS"
4. Write only the approved updates

Never reverse this: don't ask the user "which files do you want to update?" That hands the wrong layer of judgment to the wrong person.

Reference

• Full methodology (the why, all 16 traps, evolution story): ${CLAUDE_PLUGIN_ROOT}/METHODOLOGY.md
• Templates (what scaffold.sh copies): ${CLAUDE_PLUGIN_ROOT}/templates/
• Doctor (structural health check): bash "${CLAUDE_PLUGIN_ROOT}/scripts/doctor.sh" <user-project-root>
• Public repo: https://github.com/Ethan-YS/project-brain