You'll notice
Guidance for checking a background agent's output now says to send it a message instead
What
When a background agent (a task Claude Code has running in the background) is still in progress, the guidance text shown changed from "You can check its output using the [tool] tool" to "Send it a message with [tool] to retrieve its result."
Why
This changes how Claude is told to interact with a running background agent, framing it as sending a message rather than just checking output, which should make Claude use the tool the way it's actually meant to be used.