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.
Overlong message recipients are rejected by the schema
Under the hood
Useful1Signal1
Session Messaging
An overlong recipient name in the messaging tool now fails validation right away.
What's wrong with this entry?
Anonymous. No account, no email.
What
The messaging tool's recipient field gained a length bound alongside the existing single-line check, so an overlong recipient fails validation immediately rather than later during resolution.
Details
The rejection message says the value "must be a single-line recipient name or address".
Evidence
must be a single-line recipient name or address
Strings lifted out of the shipped bundle, so the claim above can be checked against them.