/brain:rescan --- Incremental Knowledge Rescan

Detects what changed since the last scan and updates the brain DB with new knowledge.

Prerequisites

• project_brain.db must exist in the project folder (or parent). If not found, tell the user: "No brain DB found. Run /brain-init first."
• At least one project must exist in the DB.

Procedure

Step 1: Run the scanner

python3 ~/.claude/skills/brain/scripts/brain/brain_cli.py scan

Check the output:

• If is_first_scan: true → this folder was never scanned. Tell the user and proceed with full scan.
• If new_files: 0 and changed_files: 0 → "Everything up to date. No changes since last scan ({last_scan})." → done.
• Otherwise, show the delta:

RESCAN DELTA
============
Last scan:      {last_scan}
New files:      N
Changed files:  N
Removed files:  N
Unchanged:      N

New/changed files:
  + docs/NewDoc.html          (new)
  ~ CLAUDE.local.md           (changed)
  + emails/Latest_Thread.txt  (new)

Knowledge sources:
  CLAUDE.local.md:  found / not found (changed: yes/no)
  Memory files:     N files (N new/changed)
  Documents:        N new, N changed
  Emails:           N new, N changed

Step 2: Process only new/changed files

Follow the same extraction logic as /brain-init Step 4, but only for files in the delta:

If CLAUDE.local.md is new or changed:

• Re-read and extract entities, decisions, events
• Use upsert_entity so existing entities get updated rather than duplicated
• For decisions: check existing decisions in DB, only add genuinely new ones (compare decision text)

If memory files are new or changed:

• Read only the new/changed memory files
• Extract project decisions, system references

For new/changed documents and emails:

• Register as document entities via upsert_entity
• Metadata includes path, type, size

For removed files:

• Do NOT auto-delete entities. Just report: "N files removed since last scan. Their brain entities are preserved — delete manually if needed."

Step 3: Present extraction summary

RESCAN RESULTS
==============
Project: {name} ({slug})

New/updated entities:    N (list)
New decisions:           N (list)
New events:              N (list)
New document entities:   N (list)
Skipped (unchanged):     N files

Total proposed writes: NN

Ask: "Write to brain? [Y/n/adjust]"

Step 4: Execute writes and update manifest

Same write order as /brain-init Step 6:

1. Entities (upsert)
2. Relationships
3. Decisions (dedup check)
4. Events (dedup check)
5. Document entities (upsert)

After all writes, sync to MemPalace and brain.json:

from brain.memory_bridge import full_sync
full_sync("project_brain.db", project_slug)

Then update the manifest:

python3 ~/.claude/skills/brain/scripts/brain/brain_cli.py scan-update

Step 5: Report

BRAIN UPDATED (rescan)
======================
Entities:      +N, ~N updated (total: N)
Decisions:     +N (total: N)
Events:        +N (total: N)
Documents:     +N (total: N)

Manifest updated: N files tracked
Next scan will only process changes after {now}.

When to use /brain-rescan vs /brain-update

Scenario	Use
End of conversation session	/brain-update (extracts from conversation)
New files added to project folder	/brain-rescan (extracts from files)
Updated CLAUDE.local.md	/brain-rescan
First time in a project with existing brain	/brain-init (handles both init + scan)
Periodic refresh	/brain-rescan