DL-291

Agents and client UIs address channels and topics by NAME, not id — request-input channel/topic fields on the agent tool surface are name-typed, resolved viewer-scoped at the service edge (ChannelByNameForViewer: miss ≡ invisible ≡ merged not_found; a multi-hit errors invalid_argument, never auto-picks); response/stored/event fields stay id-typed. Extends DL-269/DL-270 from accounts to channels + topics.

Status: Active (Matt, 2026-08-30)

Record: ../../agent/compass-agent-peer-dm/design.md#ledger-delta