Slack delivers user mentions as opaque IDs (<@U123>). The agent had no
way to tell one participant from another — or from itself — so it could
misread a mention of a human as a self-mention and answer messages
addressed to that person (the "bot thinks it's @someone-else" bug).
Two cooperating fixes:
- _humanize_user_mentions rewrites remaining <@UID> tokens (the bot's
own mention is stripped earlier) to @DisplayName in the trigger text
and reply_to_text — the Slack equivalent of Discord's clean_content.
Handles the labelled <@UID|handle> form; unresolvable IDs fall back
to the raw ID.
- _build_identity_prompt injects an ephemeral per-turn system-prompt
line via the channel_prompt seam (applied at API-call time, never
persisted — prompt caching preserved) naming the bot's own workspace
handle (per-team in multi-workspace installs) so the agent has a
positive "that's me" anchor.
Salvaged from #55340 by @benbarclay, rebased over the workspace-scoped
user-name cache (team_id-aware resolution) on main.
5d747a91c4