Under the hoodTier: how much it should matter to you
2Useful: my rating, 1 to 5
4Signal: worth watching, 1 to 5
Claude DesignArea: what it touches
Internal ChangesKind: in v2.1.284,
What probably matters to youSection of the release
Unclear Where Claude Code actually shows this new message could not be found.
What
Claude Code now includes this error message: "Claude Design cannot be signed in from inside a Claude Code session. Start the editor outside the session and try again." It sits beside an existing refusal that applies when CLAUDE_CODE_CHILD_SESSION is set, which Claude Code sets for programs it starts itself.
Why
If you see this message, start the editor from a normal terminal rather than from inside Claude Code, then sign in again.
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Confirmed sinceAnthropic's documentation has since written up CLAUDE_CODE_CHILD_SESSION, on Agent SDK reference - TypeScript.If your application runs prompts on its own schedule, declare each run so Claude Code frames the turn to the model as a scheduled task rather than as live input from the user. Start the session with `CLAUDE_CODE_HOST_SCHEDULED_RUN` set to …agent-sdk/typescriptsee the edit
How sure we are
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubtWhere Claude Code actually shows this new message could not be found.
Anthropic's documentation agreesAnthropic's documentation has since written up CLAUDE_CODE_CHILD_SESSION, on Agent SDK reference - TypeScript.
