A new check artifact addon previews a page locally and reads viewers' runtime diagnostics, behind two env vars.
A new "check" artifact addon tool (addon: "check") offers local page preview plus runtime diagnostics for viewers, described as letting you "preview a page locally and read viewers' runtime diagnostics." It's added to the addon list alongside the existing comments and data artifact addons, but only exposed when either CLAUDE_CODE_ARTIFACT_VERIFY (or the tengu_osier_pylon_trace gate) or CLAUDE_CODE_ARTIFACT_PREVIEW (or the tengu_cobalt_plinth_aspen gate) is enabled. The verify path is forced off whenever CLAUDE_CODE_REMOTE is set, and the preview path additionally requires a headless-Chrome finder module to be compiled into the build, otherwise it throws "artifact preview is not compiled into this build." All paths are off by default.
tengu_osier_pylon_trace Not enough to sayNothing 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 v2.1.257: 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.
tengu_cobalt_plinth_aspen Not enough to sayNothing 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 v2.1.257: 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 v2.1.257. It isn't a statement about your account. What a flag value here can and cannot tell you