Claude Code gets a diff panel! See your changes side by side in fullscreen mode!

Hi, I'm Shii-chan! A new Claude Code release just came out, so let me walk you through what's worth knowing!

Claude Code Release github.com

What was announced?

This is the changelog for Claude Code Release v2.1.260, posted on GitHub Releases. The headline feature is a new diff panel that opens beside the conversation in fullscreen mode, letting you see your uncommitted changes update as Claude edits. You can toggle it on and off with the /diff command.

On top of that, there's a batch of smaller but genuinely useful additions and bug fixes.

What changes

Here are the additions worth calling out.

• Diff panel: opens beside the conversation in fullscreen mode and shows your uncommitted changes as Claude edits. Toggle it with /diff
• Prompt-cache miss reasons: /cost and the status line's prompt_cache field now show a likely cause for cache misses, like tool definitions or the system prompt changing, or being idle past the TTL
• Headless /reload-plugins: now available in headless sessions too, and listed in the Claude Code Desktop and SDK command lists
• Text-form /advisor: /advisor, /advisor <model>, and /advisor off are now available for the desktop app, Remote Control, and other headless (-p / Agent SDK) sessions

If you've ever wondered why a given turn didn't hit the prompt cache, just seeing the likely cause should already save you some guesswork.

Dive Deep

A few of the permission-related fixes look like they'll have a fairly wide impact.

• Fixed Edit / Write / Read permission rules whose path contains parentheses being dropped as invalid or ignored by the Bash sandbox, which could leave a folder meant to be read-only actually writable
• Fixed a single file permission rule with an uncompilable pattern (like an unclosed [) making every file edit fail with an Invalid regular expression error. Such a deny rule now guards the literal path it spells instead
• Fixed Bash permission checks auto-approving zsh commands that hide a command substitution inside a REPORTTIME, REPORTMEMORY, or DIRSTACKSIZE assignment; these now prompt for approval like they should

Beyond that, there's a wide range of smaller fixes covering Bedrock model discovery, AWS SSO/STS credentials, the /status display, and missing keys in skillOverrides, among others.

Wrap-up

• A new diff panel shows your uncommitted changes side by side in fullscreen mode, toggled with /diff
• Prompt-cache miss reasons now show up in /cost and the status line
• /reload-plugins now works in headless sessions, and text-form /advisor was added
• Fixed bugs where parentheses or uncompilable patterns in permission rules broke file edits, and closed a zsh command-substitution loophole

If you edit code with Claude Code every day, the diff panel and the cache-miss reasons alone are worth checking out!