New messaging surfaces answer only when mentioned

A bot added to a busy channel should not answer every conversation between the people in it. Slack, Telegram and iMessage surfaces now have one setting that decides when the bot replies to a channel message that does not mention it: channelResponseMode, on the surface's inbound config.

• mention answers mentions, direct messages, and threads the bot is already part of. Everything else in the channel is left alone.
• always answers every channel message, which is how Slack surfaces behaved by default until now. An optional keywords filter (require and ignore lists, whole-word and case-insensitive) narrows which unmentioned messages it answers.
• judge is reserved for an upcoming feature that decides from context whether a reply is wanted. Today it behaves as mention.

New surfaces default to mention. A Slack, Telegram or iMessage surface created from the dashboard, the API, MCP, the SDK or a template stores channelResponseMode: "mention" unless you choose otherwise.

Existing surfaces keep their behavior. Every existing surface was stamped with the mode that matches what it does today: a Slack surface that answered every message is always, one set to answer only when mentioned is mention. A Telegram surface keeps its mention-or-reply behavior, and one that processed every group message is always. iMessage group chats keep their mention patterns under mention.

Change the mode in the surface's inbound settings under Channel response mode, or with inbound.channelResponseMode on the surface update API. Per-channel overrides are available through inbound.channelOverrides. The Slack triggerOnMention setting still works as an alias for one release and is deprecated in favor of channelResponseMode.