Source Intelligence

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.

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Claude Code v2.1.212

Artifact Syntax Highlighting (tengu_artifact_hljs_highlight)

Feature flag
tengu_artifact_hljs_highlight Not enough to say

Nothing here resolved what this flag was doing on this version, so nothing here should be read as on or off.

This account: no value returned · anonymous baseline: no value returned · compiled default in v2.1.212: off

These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.

Read once, for one account on one subscription tier, against v2.1.212. It isn't a statement about your account. What a flag value here can and cannot tell you

Published artifacts that contain fenced code blocks now include an inline highlight.js (hljs) runtime for client-side syntax highlighting. The runtime is appended only when the artifact contains recognizable language classes.

Details
  • Feature-flagged via tengu_artifact_hljs_highlight (default: true).
  • The hljs bundle is loaded from /$bunfs/root/hljsBundle.generated.min.js and embedded inline so artifacts remain standalone.
  • A per-artifact token budget limits how much code gets highlighted to keep page load fast.
  • The runtime is validated before injection; unsafe bundles are rejected.
  • The artifact footer note now reads: "— includes the inline syntax-highlight runtime (~1MB), appended because the page contains fenced code"
Evidence

"bundle contains an hljs runtime sentinel" (search for "tengu_artifact_hljs_highlight")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

See this entry in the whole of v2.1.212 →