Under the hoodTier: how much it should matter to you
2Useful: my rating, 1 to 5
3Signal: worth watching, 1 to 5
Background TasksArea: what it touches
ImprovementsKind: in v2.1.234,
ImprovementsSection of the release
What
Automated background-task events delivered on your turn are now wrapped in a <system-reminder> envelope, and any closing tag inside the payload is escaped to </system-reminder> so content coming back from a task cannot close the reminder early and start speaking as the harness.
Details
The escape is a case-insensitive global replace over the payload before wrapping.
The subagent prompt was updated to match: worker results arrive as user-role messages containing <task-notification> XML, delivered as harness input inside a reminder, and the model is told never to reproduce them in its own output.
The multi-agent example transcript now shows the nesting too.
Active on this build wherever task notifications are delivered.
Evidence
Worker results arrive as user-role messages containing \<task-notification>\ XML, delivered as harness input, normally inside a \<system-reminder>\ that opens with, <task-notification>
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
How sure we are
One source agreesOne thing we can check says the same as this entry.
Anthropic's release notes agreeBackground task notifications delivered between turns are now sent to the model inside <system-reminder> tags, matching mid-turn delivery
