# Brain Interface Implementation Complete

## What was built
- ops/brain/ with 4 scripts: brain-query, brain-push, brain-pull, brain-status
- Shared Python module _brain_common.py with zero external dependencies
- Session logging at .brain/sessions/
- Source inventory sync at .brain/inventory.json

## Key decisions
- Bash + Python hybrid: bash wrappers call Python for API/JSON work
- Query bridge uses Gemini 2.5 Flash with local source mirrors as grounding context
- Local mirror in handoffs/ is always written before API push (nothing lost on failure)
- All scripts callable from any working directory via project root resolution

## Known limitations
- NotebookLM API has no chat/query endpoint — bridge uses Gemini with source content
- Source GET returns metadata only, not content body — must maintain local mirrors
- NotebookLM API does not support notebook rename or delete