Starting a cloud session gives clearer notices and errors

What

A cloud session is a Claude Code session that runs on Anthropic's servers instead of your own computer. When you start one from your terminal, Claude Code now reports more, and more carefully:

• A notice now appears when your local git branch is ahead of the remote copy, and it says how many commits ahead it is.
• A new unusable_session_id error appears when the server returns a session id that this version of Claude Code cannot use. The error tells you a session may have been created anyway and points you to claude.ai/code to check. Before, the only check of this kind was for a reply with no session id at all.
• Error messages from the server are now cleaned up before they are shown, and some may be hidden.
• Branch names shown in errors for --on-branch and --ref are now cleaned up before they are shown.
• The error shown when no suitable environment is found now lists cleaned-up environment names instead of raw ones. When the list is longer than 1500 characters it shows a count instead. The raw list (name, id and kind of each environment) is written to the log.

Why

The ahead-of-remote notice tells you that commits you have not pushed will not be in the cloud session. The unusable_session_id error tells you to check claude.ai/code before you try again, so you can see whether a session already exists before you start another.