Claude Code v2.1.251 Changelog

What's new

• Smarter model switching: If you switch between different AI models (like going from a faster one to a smarter one), you can now set up automatic checks to confirm, block, or just track that switch.
• Live subagent streaming: When a background helper bot (a "subagent") is working on a task, you can now watch its tool usage and results stream live on your screen.
• Spending limits: You can now see a visual "Spend limit" bar. This helps teams track how much money they are spending on AI processing so they don't go over budget.
• Cache tracking: When the AI remembers parts of your previous chat to save time and money (called a "prompt cache"), you can now see detailed stats on how well that's working.
• New terminal commands: Helpful commands like attach (to jump back into a background task), logs, stop, and rm (remove) are now properly listed in the help menu.

Improvements

• Lower CPU usage: The app won't waste your computer's processing power by constantly redrawing the screen while it's thinking.
• Smaller file size: The app takes up about 5 MB less space on your hard drive.
• Better error messages: If a network connection drops, the app now tells you exactly *why* it failed instead of just saying "connection reset." It also gives clearer warnings about missing file links.
• Clearer bot messaging: When a helper bot sends a message, Claude now correctly understands it's from a worker inside your current session, rather than getting confused and thinking it's a totally different app.
• Better text selection in tmux: If you use a terminal multiplexer like tmux over a remote SSH connection, copying and pasting text now works exactly the way you'd expect it to.

Fixes

• Symlink security holes: Fixed a big security issue where file-reading tools could follow "symlinks" (shortcuts) to accidentally read or write files outside the folder you approved.
• Plugin security: Fixed a bug where add-on plugins could sneakily point to files they weren't supposed to access.
• Frozen conversations: Fixed an issue where the chat would get permanently stuck if the AI thought about a response but didn't actually write any text out loud.
• Team communication: Fixed bugs where helper bots (subagents) couldn't send their final answers back to the main bot in charge, leaving the team "stuck."
• Glitchy background tasks: Fixed screen lag that happened when you had a lot of helper bots running at the same time—they used to pile up text on the screen, but now they update smoothly.
• Silly AI suggestions: Fixed a glitch where the app would suggest "switch to a bigger context window" even if you were already using the biggest one available.
• Git worktree fixes: Background bots can now actually edit files inside "git worktrees" (temporary branches of your code) that they created.
• Emacs and Micro editors: Fixed a crash that happened when trying to use keyboard shortcuts in certain text editors running in the background.
• Crash on startup: Fixed a bug where a hidden, invalid character (a "null byte") in your folder settings would crash the app as soon as you tried to open it.
• Accidental approvals: Fixed a bug where the AI would automatically approve certain math commands in the terminal without asking you for permission first.

Breaking changes

No breaking changes in this release.