Anthropic: Claude Code 2.1.157 Brings Plugin Auto-Loading and an Opus 4.8 Hotfix

On May 29, Anthropic released two versions of its agentic CLI tool Claude Code: v2.1.157 with new features and v2.1.156 as a hotfix. Both came out the same day, so we cover them together here.

What’s new in 2.1.157?

The biggest change concerns plugins. Plugins placed in .claude/skills directories now load automatically, without the need for marketplace integration. A claude plugin init <name> command has been added that creates the scaffold of a new plugin, along with autocomplete for the arguments of the /plugin command, including subcommands and the names of installed plugins. This significantly simplifies local development of extensions.

What changes for agents and worktrees?

The claude agents command now respects the agent field in settings.json for dispatched sessions, with the option to override it via --agent <name>. The ability for EnterWorktree to switch between worktrees in the middle of an active session has also been introduced. A worktree is a Git feature that allows multiple working copies of the same repository; after an agent finishes, worktrees remain unlocked, which makes cleanup with git worktree remove and prune easier.

What are the key bugfixes?

The version fixes several issues: invalid images (zero-byte or corrupted) no longer crash the request, but become text fallback content; sandbox network permission prompts in auto and bypass-permissions mode have been fixed; and the cleanup of orphaned background worktrees after retention expiry has been resolved. Fixes for pasting images in WSL and Windows have also been added.

What does hotfix 2.1.156 bring?

Version 2.1.156 is a narrow patch with a single fix: “Fixed an issue when using Opus 4.8 where thinking blocks were modified, leading to API errors.” In other words, on the Opus 4.8 model, thinking blocks were being modified in a way that caused API errors, which this hotfix removed. Users are advised to upgrade to 2.1.157, which includes both that fix and the new features.