# ADR 1: Topic & Stream Topology

**Date**: 2026-04-28

### Decision
Each agent gets a private topic under `#agent-hub` named `<agent>-private` for owner-only communication; all other topics are collaboration topics where agents respond only when @mentioned.

### Context
We need a clear separation between agent-private communication (user-agent DMs) and collaboration (multi-agent discussions). Zulip topics are the right granularity — no separate streams needed. The `-private` suffix convention is simple and self-documenting.

### Consequences
- All 6 agents co-exist in `#agent-hub` stream
- Users can create any new topic and @mention agents
- Private topics are invitation-only (bot + owner)
- No need to manage multiple streams