You'll noticeTier: how much it should matter to you
4Useful: my rating, 1 to 5
3Signal: worth watching, 1 to 5
SessionsArea: what it touches
ImprovementsKind: in v2.1.285,
What probably matters to youSection of the release
What
A background session is a Claude Code conversation that keeps running without a terminal window attached to it. Before, choosing one in /resume or with claude --resume stopped with a message saying the session was still running, and told you to run claude attach or claude stop. Now Claude Code tries to open it for you:
The session is opened as if you had run claude attach <jobId>, and Claude Code prints "Opening ..., running in the background".
If you gave a prompt, it is first sent to that session so it runs as the next turn.
Before handing over, Claude Code checks that the background session is running the same Claude Code build. If it is not, you get an ESKEW error.
This needs an interactive terminal for both input and output. It does not happen with conflicting flags such as an --output-format other than text.
The path sits behind tengu_resume_open_live_bg, whose built-in fallback is on when the server sends no value.
If opening fails or a launch prompt is still pending, a screen explains why. It now shows the session title followed by " is running in the background". It also says whether your prompt was queued, not confirmed, or not sent, and still suggests claude attach, claude stop and claude --resume ... --fork-session. A separate message tells you when your latest conversation is running in the background. It points to claude agents or claude --resume, and adds --fork-session when forking into a new copy is possible.
Why
Resuming a busy background session no longer dead-ends, and a prompt you typed is not silently lost. You are told what happened to it.
Read from
Names in the bundle--resumeclaude attachclaude stop
Feature flag
tengu_resume_open_live_bgNot enough to say
Nothing here resolved what this flag was doing on this version, so nothing here should be read as on or off.
This account: no value returned · anonymous baseline: no value returned · compiled default in v2.1.285: on
These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubtThe full set of cases where the handoff applies instead of the refusal is not established.
Anthropic's release notes agreeAdded claude --desktop to open the Claude desktop app on the current directory, or on a session with --continue / --resume <id>
The name it cites is new in this buildNew in this build: tengu_resume_open_live_bg
