Source Intelligence

DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

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Claude Code v2.1.229

queued_notification added to the stdout message protocol

Under the hood
Useful2 Signal4
Terminal UI

Claude Code can now buffer notifications and redeliver undrained ones when you resume a session.

What

The message types Claude Code emits on stdout gained a queued_notification entry carrying an id, origin, content, a priority of "now", "next" or "later", and a queue timestamp. It is the wire format behind the ReadNotifications tool: the CLI buffers the event, nudges the model to drain it, and only acknowledges it once drained, so an undrained event is redelivered when the session resumes.

Evidence

The CLI buffers it, nudges the model to call the ReadNotifications tool, and acks the event processed only when drained — an undrained event redelivers on resume.

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

See this entry in the whole of v2.1.229 →