Claude Code v2.1.323 adds Code Mode, plugin version gating and hook heartbeats

Anthropic published Claude Code v2.1.323 on November 12, 2026. The release adds Code Mode, an experimental opt-in feature in which Claude writes JavaScript to call its tools. Users can turn it on or off, and administrators can turn it off for an organization. The documentation covers the setup steps.

The update also changes how plugins are handled. A plugin’s plugin.json can now declare an engines["claude-code"] range. Plugins outside their stated Claude Code version range are not installed, updated or loaded, and install and update commands select the newest version that fits. The claude plugin validate command now type-checks a plugin’s TypeScript hooks module, reporting each finding as a warning, and --strict treats those warnings as failures.

Other changes cover usage limits, hooks and developer tooling. When a model needs usage credits that are turned off or used up, an options menu offers to stop, switch to usage credits or upgrade. Hooks that run long in claude -p and SDK sessions now emit a progress heartbeat every 30 seconds, which is meant to keep hosts such as Claude Desktop from marking the turn as hung. A fix addresses running /compact.

Why it matters

Plugin version ranges reduce the chance that an incompatible plugin breaks a working setup. The hook heartbeat matters for teams that run Claude Code headlessly or through the SDK, where a silent hook could otherwise look like a failure. Code Mode changes how Claude calls tools, so teams should test it before relying on it.

What to do

Check whether your plugins declare a version range and run claude plugin validate --strict on any custom hooks. Keep Code Mode off in production until you have tested it. For Claude Desktop behavior, such as the heartbeat and CLAUDE_CODE_AUTO_MODE_MODEL support, confirm on Anthropic’s site when Claude Desktop includes this version.