# Builder ↔ Rivet Communication Protocol
**Established:** 2026-02-16 02:17 AEDT
**After:** Communication failure incident (Feb 15-16)

## Files
- `BUILDER-INBOX.md` — Rivet writes TO Builder (append-only)
- `RIVET-INBOX.md` — Builder writes TO Rivet (append-only)

## Rules
1. **Writer appends with timestamp, never edits previous entries**
2. **Reader acknowledges by writing "ACK [timestamp]" in THEIR OWN inbox**
3. **Neither agent touches the other's inbox file**
4. **Gateway bridge = secondary notification only, not delivery mechanism**
5. **If no ACK after 1 hour, re-send**

## Daily Archive (Rivet's job, 8am AEDT)
1. Read both inbox files
2. Write daily summary to `memory/comms/YYYY-MM-DD.md`
3. Move COMPLETED + ACKNOWLEDGED items to archive
4. Leave open/unfinished/unACK'd tasks in live inbox
5. Clear completed items only

## What stays in live inbox:
- Unacknowledged tasks
- Tasks marked "in progress"
- Blockers waiting on Michael

## What gets archived:
- Completed + acknowledged items
- Status updates that have been read
- Resolved discussions