Relayed messages from a project's coordinator session are held in order and announced to Claude

What

Claude Code added handling for messages relayed from a project's coordinator session, the main session that hands work to other sessions in a multi-session setup.

• On the main thread, a queued relay message from the coordinator (one carrying hearthRelayMessageIds that is meant to be sent to Claude) is taken out of the normal queue, and any later ordinary prompt queued behind it waits too, unless it comes from Slack and is not a verified human Slack turn. A separate path detects these relay messages during a turn.
• Claude can be shown a reminder that a message from the project's coordinator session is waiting and will arrive after the current turn ends. The wording can be replaced remotely through tengu_harmonic_cook; otherwise a built-in sentence is used.
• This is controlled by tengu_squishy_newt, whose built-in fallback is on, and can be overridden with the environment variable CLAUDE_CODE_SQUISHY_NEWT. Nothing has been read about either switch.
• The record written when queued messages are delivered now counts how many arrived over a relay. The waiting time also appears to be measured from the oldest message now; the old code wrote the earliest time into the wrong value.

Why

In coordinator setups this changes the order in which queued prompts reach Claude, so ordinary prompts do not overtake a relayed coordinator message, and Claude knows one is coming. It only concerns sessions that receive relayed coordinator messages.