tengu_cobalt_plinth_bracken
A Claude Code feature flag, read out of the shipped bundle. It has been in the build since v2.1.216, including the newest one read.
You could start a private artifact from a published template, but two server switches keep it shut here.
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.236.
In the changelogs
5Releases whose published page names tengu_cobalt_plinth_bracken.
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v2.1.273
Artifact publish now pre-reserves a slug, but only when multi-file artifacts are enabled
Publishing a brand-new artifact can now reserve its address in advance, when a related setting is enabled
gate cited by this entry
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v2.1.260
Artifact asset store gains a server-side copy_from action
Artifact assets can now be copied server-side between artifacts without downloading them.
gate cited by this entry
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v2.1.257
Artifact multi-file feature gains env override
A new env var can switch on multi-file artifact support without waiting for the feature flag.
gate cited by this entry
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v2.1.239
Artifact tool gains a
readaction, with multi-file browsing and delete built but gated offClaude can now read back a published artifact's contents; browsing, multi-file publishing and deletion are built but off.
gate cited by this entry, found in this entry's text
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v2.1.236
Artifact types (templates and starters), built end to end and off by default
You could start a private artifact from a published template, but two server switches keep it shut here.
gate cited by this entry, found in this entry's text
Gate readings
5| Release | Resolved | This account | Anonymous | Compiled default |
|---|---|---|---|---|
| v2.1.273 read on another version | Off by default, switched on for this account | on | on | off |
| v2.1.260 read on another version | Off in both readings | off | off | off |
| v2.1.257 read on another version | Off in both readings | off | off | off |
| v2.1.239 | Off in both readings | off | off | off |
| v2.1.236 | Off in both readings | off | off | 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.
Flag server, over time
14| Read as | Reading | From | Until | Version installed |
|---|---|---|---|---|
| anonymous | on | 2026-10-17T05:30:04Z | 2026-10-22T06:25:04Z | v2.1.302 to v2.1.308 |
| this account | on | 2026-09-11T02:35:04Z | 2026-10-22T06:25:04Z | v2.1.268 to v2.1.308 |
| anonymous | no longer carried | 2026-10-17T05:25:57Z | 2026-10-17T05:25:57Z | v2.1.302 |
| anonymous | on | 2026-09-11T01:50:04Z | 2026-10-17T05:10:04Z | v2.1.268 to v2.1.302 |
| this account | off | 2026-09-10T21:47:12Z | 2026-09-11T01:50:04Z | v2.1.268 |
| anonymous | off | 2026-08-19T04:25:04Z | 2026-09-10T23:05:05Z | v2.1.233 to v2.1.268 |
| this account | no longer carried | 2026-09-10T21:46:45Z | 2026-09-10T21:46:45Z | v2.1.268 |
| this account | off | 2026-09-08T20:36:15Z | 2026-09-10T17:40:05Z | v2.1.263 to v2.1.267 |
| this account | no longer carried | 2026-09-08T20:34:58Z | 2026-09-08T20:34:58Z | v2.1.265 |
| this account | off | 2026-09-06T02:40:05Z | 2026-09-08T18:45:05Z | v2.1.261 to v2.1.263 |
| this account | no longer carried | 2026-09-06T02:36:19Z | 2026-09-06T02:36:19Z | v2.1.263 |
| this account | off | 2026-08-14T22:10:05Z | 2026-09-06T01:55:04Z | v2.1.232 to v2.1.261 |
| anonymous | no longer carried | 2026-08-19T04:20:14Z | 2026-08-19T04:20:14Z | v2.1.233 |
| anonymous | off | 2026-08-14T22:10:05Z | 2026-08-19T03:45:04Z | v2.1.232 to v2.1.233 |
One row per unbroken stretch of one reading, newest first, from snapshots taken every twenty-five minutes or so. No longer carried is not off: it means the flag server stopped returning the gate at all, which is what a retired experiment looks like. The version column is what was installed when the reading was taken, not what caused it.
First cited
1The earliest release whose published evidence quoted tengu_cobalt_plinth_bracken was v2.1.236, 19 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
1Build by build
81One 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.