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Sweep 28 Aug 2026 · 00:00Z Build v2.1.250 478 read Stable v2.1.236 Latest v2.1.250 Next v2.1.250 Feeds RSS JSON llms.txt

DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

Reference / Feature flags

tengu_artifact_hljs_highlight

A Claude Code feature flag, read out of the shipped bundle. It was in the build from v2.1.212 and was gone by v2.1.239.

What it is

Artifact syntax highlighting and mermaid diagrams are now always on; three other gates were renamed and stay off.

Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.239.

Presence across releases

ReleasesReadingDeclared typeDefault
2.1.245 – 2.1.250 5 releases never mined — —
2.1.239 – 2.1.243 5 releases not in the build — —
2.1.212 – 2.1.238 26 releases in the build — bool:true

A row reading never mined is a release with no archived bundle behind it. Nothing was read out of it, so nothing here says whether the name was in it. A declared type or a default is only ever what that release's own bundle stated.

Gate readings

ReleaseResolvedThis accountAnonymousCompiled default
v2.1.239 Not enough to say no value returned no value returned not a boolean we can read
v2.1.212 read on another version Not enough to say no value returned no value returned off

Two arms, because they disagree: this account is the one account this site reads and anonymous is a baseline with no identity attached. A reading says nothing about your account, and off cannot rule out a rollout both readings sit outside of. What these readings can and cannot show.

Changelog entries naming it

  1. v2.1.239Three feature gates renamed, three retired

    Artifact syntax highlighting and mermaid diagrams are now always on; three other gates were renamed and stay off.

    gate cited by this entry

  2. v2.1.212Artifact Syntax Highlighting (tengu_artifact_hljs_highlight)

    gate cited by this entry

Documentation pages

None of Anthropic's documentation pages this site has a copy of carries this name.

Names beside it

Every feature flag in the inventory starting tengu_artifact, up to twelve of them.

tengu_artifact_mermaid_diagramsArtifact syntax highlighting and mermaid diagrams are now always on; three other gates were renamed and stay off. 2.1.202 tengu_artifact_previewAn artifact preview action would screenshot a page locally at several widths, but it cannot run here. never mined tengu_artifact_reject_breakerThe Artifact tool stops looping after three identical failures and reports the problem to you. never mined tengu_artifact_thumb_directNo description from anybody. 2.1.208 tengu_artifact_verifyClaude could read console errors and failed loads from real viewers of an artifact, but it's switched off. never mined tengu_artifact_verify_republishClaude could read console errors and failed loads from real viewers of an artifact, but it's switched off. never mined

Read out of the published npm bundle release by release, and out of Anthropic's own documentation as this site captured it. Nothing on this page is a description anybody here wrote about what the feature flag does. All feature flags.