# ADR 5: @mention Detection via Zulip SDK

**Date**: 2026-04-28

### Decision
Use the Zulip SDK's `mentioned_users` field in message events for @mention detection, with regex fallback for cleaning @mention artifacts from forwarded message text.

### Context
The Zulip event API provides `mentioned_users` — an array of user IDs that were @mentioned in the message. This is the most reliable detection mechanism (handles all @mention formats) and avoids fragile text parsing. Regex is only needed to strip the `@**Display Name**` markup from the forwarded message body.

### Consequences
- Zero false positives for @mention detection
- Handles @all-bots, @everyone, and individual @mentions uniformly
- Stripped message text is clean for agent consumption
- SDK handles reconnection and backoff for the event stream