/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