What it is
A gate decides which of two error codes an interrupt-triggered abort reports.
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.257.
Presence across releases
1Build by build
21One 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_fizzy_grove was v2.1.257, 1 Sep 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
2| Release | Resolved | This account | Anonymous | Compiled default |
|---|---|---|---|---|
| v2.1.280 read on another version | Not enough to say | no value returned | no value returned | off |
| v2.1.257 read on another version | Not enough to say | no value returned | no value returned | 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.
Names beside it
Every feature flag in the inventory starting tengu_fizzy, up to twelve of them.
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.