tengu_rustling_lantern
A Claude Code feature flag, read out of the shipped bundle. It was in the build from v2.1.310 and was gone by v2.1.312.
A remote switch can now swap in alternate instruction text for some tools, and the existing text is used unless it is switched on remotely
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.310.
In the changelogs
2Releases whose published page names tengu_rustling_lantern.
-
v2.1.312
A remotely controlled switch is now fixed to off in the code
Claude Code no longer checks one remote switch, so whatever it controlled stays off whatever Anthropic's servers send
gate cited by this entry, found in this entry's text
-
v2.1.310
Some tool instructions gain an alternate wording that is off by default
A remote switch can now swap in alternate instruction text for some tools, and the existing text is used unless it is switched on remotely
gate cited by this entry
Gate readings
2| Release | Resolved | This account | Anonymous | Compiled default |
|---|---|---|---|---|
| v2.1.312 read on another version | Not enough to say | no value returned | no value returned | not a boolean we can read |
| v2.1.310 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.
First cited
1The earliest release whose published evidence quoted tengu_rustling_lantern was v2.1.310, 23 Oct 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
2Build by build
3One 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.