tengu_hidden_frog
A Claude Code feature flag, read out of the shipped bundle. It has been in the build since v2.1.259, including the newest one read.
A new internal boolean gate was added and defaults to false, with no stated purpose.
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.259.
In the changelogs
4Releases whose published page names tengu_hidden_frog.
-
v2.1.269
tengu_hidden_frog flag moved from a UI auto-enable check to reactive-compact fallback
The reactive-compact fallback now depends on
tengu_hidden_frogat a new call site with a different default, while its old UI use was disabled.gate cited by this entry, found in this entry's text
-
v2.1.269
tengu_hidden_frog gate: old accessor hardwired off, capability moved to a new function with flipped default
The tengu_hidden_frog capability moved to a new function whose default flipped from off to on
gate cited by this entry, found in this entry's text
-
v2.1.260
Reactive-compact "summarize everything" fallback continues to depend on an experiment flag
The reactive-compact summarize-all fallback still depends on the same experiment flag as before.
gate cited by this entry
-
v2.1.259
New tengu_hidden_frog gate
A new internal boolean gate was added and defaults to false, with no stated purpose.
found in this entry's text, named in this entry, gate cited by this entry
Gate readings
3| Release | Resolved | This account | Anonymous | Compiled default |
|---|---|---|---|---|
| v2.1.269 | On for this account, and not off by default | on | on | on |
| v2.1.260 read on another version | Not enough to say | no value returned | no value returned | off |
| v2.1.259 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.
Flag server, over time
7| Read as | Reading | From | Until | Version installed |
|---|---|---|---|---|
| this account | on | 2026-09-11T22:50:04Z | 2026-09-23T09:25:04Z | v2.1.269 to v2.1.280 |
| anonymous | on | 2026-09-11T19:35:04Z | 2026-09-23T09:25:04Z | v2.1.269 to v2.1.280 |
| this account | off | 2026-09-11T22:15:04Z | 2026-09-11T22:15:04Z | v2.1.269 |
| this account | on | 2026-09-11T19:35:04Z | 2026-09-11T22:05:04Z | v2.1.269 |
| this account | off | 2026-09-11T02:35:04Z | 2026-09-11T19:25:05Z | v2.1.268 |
| anonymous | off | 2026-09-10T23:05:05Z | 2026-09-11T19:25:05Z | v2.1.268 |
| anonymous | on | 2026-09-10T23:00:05Z | 2026-09-10T23:00:05Z | v2.1.268 |
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
2The earliest release whose published evidence quoted tengu_hidden_frog was v2.1.259, 2 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 below.
Presence across releases
1Build by build
19One 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.