Sweep 19 Sep 2026 · 02:36Z Build v2.1.278 500 read Stable v2.1.267 Latest v2.1.278 Next v2.1.278 Feeds RSS JSON llms.txt Unofficial
Claude Code v2.1.274 ·

New built-in 'diff' and 'claude-test' plugins added

Claude Code now ships built-in 'diff' and 'claude-test' plugins, loaded through a new lazy plugin-loading mechanism

TierUse it nowhow much it should matter to you
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AreaTestingwhat it touches
KindNew Featuresin v2.1.274,
Group of 2 Use it now Notable No documentation found

Claude Code now ships built-in 'diff' and 'claude-test' plugins, loaded through a new lazy plugin-loading mechanism

What

  • Two new built-in plugin bundles, named diff and claude-test, are now loaded alongside the existing built-in plugins (sec-default, agents-md, plugin-authoring, tips).
  • The claude-test plugin adds skills (claude-test, claude-test-execute, claude-test-draft), agents (explorer, author, runner), and a browser automation server so Claude Code can run plain-language specs from .claude-test/specs/ against your local dev server in a real headless browser and report pass/fail results with screenshots, via a new /claude-test command.
  • Built-in plugin registration itself was refactored from immediate registration calls into a named, lazy-loading pattern.

Why This adds a ready-to-use way to write and run browser-based tests for your app directly from Claude Code, without installing a separate plugin.

Read from
Names in the bundle/claude-test
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Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubtWhether the tengu_mellow_hollerith gate is switched on for any account is unread, so nothing can be said about its status.
The name it cites is new in this buildNew in this build: tengu_mellow_hollerith

See this entry in the whole of v2.1.274 →