What it is
Artifacts can show who else is viewing live, but only if you set an environment variable.
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.251.
Presence across releases
1Build by build
22One 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.
First cited
1The earliest release whose published evidence quoted tengu_brass_plover was v2.1.251, 28 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 above.
Gate readings
1| Release | Resolved | This account | Anonymous | Compiled default |
|---|---|---|---|---|
| v2.1.251 | 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
20| Read as | Reading | From | Until | Version installed |
|---|---|---|---|---|
| this account | on | 2026-09-10T21:47:12Z | 2026-09-22T15:25:05Z | v2.1.268 to v2.1.278 |
| anonymous | on | 2026-09-03T19:50:04Z | 2026-09-22T15:25:05Z | v2.1.259 to v2.1.278 |
| this account | no longer carried | 2026-09-10T21:46:45Z | 2026-09-10T21:46:45Z | v2.1.268 |
| this account | on | 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 | on | 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 | on | 2026-09-03T23:25:05Z | 2026-09-06T01:55:04Z | v2.1.259 to v2.1.261 |
| this account | off | 2026-09-03T23:05:05Z | 2026-09-03T23:05:05Z | v2.1.259 |
| this account | on | 2026-09-03T23:00:47Z | 2026-09-03T23:00:47Z | v2.1.260 |
| this account | off | 2026-09-03T19:25:04Z | 2026-09-03T19:50:04Z | v2.1.259 |
| anonymous | off | 2026-09-03T15:55:04Z | 2026-09-03T19:25:04Z | v2.1.259 |
| this account | on | 2026-09-02T10:05:06Z | 2026-09-03T19:05:05Z | v2.1.257 to v2.1.259 |
| anonymous | on | 2026-09-02T03:20:05Z | 2026-09-03T15:25:04Z | v2.1.257 to v2.1.259 |
| this account | off | 2026-09-02T09:25:04Z | 2026-09-02T09:25:04Z | v2.1.257 |
| this account | on | 2026-09-02T06:00:05Z | 2026-09-02T07:45:04Z | v2.1.257 |
| this account | off | 2026-09-02T03:25:04Z | 2026-09-02T03:35:04Z | v2.1.257 |
| this account | on | 2026-09-02T03:20:05Z | 2026-09-02T03:20:05Z | v2.1.257 |
| this account | off | 2026-08-28T02:55:04Z | 2026-09-02T03:00:06Z | v2.1.246 to v2.1.257 |
| anonymous | off | 2026-08-28T00:55:05Z | 2026-09-02T03:00:06Z | v2.1.246 to v2.1.257 |
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.
Names beside it
Every feature flag in the inventory starting tengu_brass, up to twelve of them.
tengu_brass_condor_loupeA remote-config gate decides whether an internal UI element shows a summary view or stays hidden. v2.1.257
tengu_brass_lanternNew startup telemetry tracks managed-config readiness and an optional live identity check v2.1.271
tengu_brass_sledNo description from anybody. v2.1.198
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.