tengu_cobalt_plinth_teasel
A Claude Code feature flag, read out of the shipped bundle. It was in the build from v2.1.248 and was gone by v2.1.300.
Publishing an artifact skips its re-read check when your last read matched the live version.
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.248.
In the changelogs
2Releases whose published page names tengu_cobalt_plinth_teasel.
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v2.1.299
Artifact requests can be sent as MCP tool calls, off by default
Some artifact requests can now travel as MCP tool calls, a path that stays off unless it is switched on remotely
gate cited by this entry
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v2.1.248
Artifact writes can skip a re-read when your own last read saw the current version
Publishing an artifact skips its re-read check when your last read matched the live version.
gate cited by this entry, found in this entry's text
Gate readings
1| Release | Resolved | This account | Anonymous | Compiled default |
|---|---|---|---|---|
| v2.1.248 | Not enough to say | no value returned | no value returned | on |
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.
First cited
1The earliest release whose published evidence quoted tengu_cobalt_plinth_teasel was v2.1.248, 27 Aug 2026. That is the oldest release this project wrote about it, so it is a floor on the name's age and not the release that introduced it. It is not a presence reading: which builds carried the name is the table below.
Presence across releases
4Build by build
51One row per release since the first build this name was read out of. Absent means the build was read and the name was not in it, never mined means no bundle for that release was ever archived, and a declared type or a default is only ever what that release's own bundle stated.
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.