Sweep 19 Sep 2026 · 02:36Z Build v2.1.278 500 read Stable v2.1.267 Latest v2.1.278 Next v2.1.278 Feeds RSS JSON llms.txt Unofficial
Claude Code v2.1.275 ·

New codenamed gates amber_astrolabe, bison_cairn, larch_cistern

New internal flags added, including bashActFirstEnabled and three codename gates amber_astrolabe, bison_cairn, larch_cistern

TierNothing to try yethow much it should matter to you
Useful1my rating, 1 to 5
Signal2worth watching, 1 to 5
AreaGateswhat it touches
KindIn Developmentin v2.1.275,
Nothing to try yet

New internal flags added, including bashActFirstEnabled and three codename gates amber_astrolabe, bison_cairn, larch_cistern

What

Claude Code adds several new internal flags:

  • bashActFirstEnabled, controlled by the experiment tengu_gorse_plover (or the CLAUDE_CODE_GORSE_PLOVER environment variable)
  • three codename-style flags, amber_astrolabe, bison_cairn, and larch_cistern, each backed by its own experiment and a matching CLAUDE_CODE_* environment variable override

Several places in the code that used to read the bison_cairn, larch_cistern, and amber_astrolabe flags directly were rewritten to instead read fields off local event objects, such as pollEmptyDispatch and ideSelection.

Why

These are internal flags for gradually rolling out unreleased behavior, so nothing changes for most users yet. The shift away from reading the flags directly at some call sites suggests those particular checks are being replaced by more targeted logic.

Read from
Feature flag
tengu_gorse_plover Off in both readings

The flag server returned off for the account this site reads and for the anonymous baseline. A reading of off cannot rule out a rollout these two readings sit outside of.

This account: off · anonymous baseline: off · compiled default in v2.1.275: not a boolean we can read

These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.

Read once, for one account on one subscription tier, against v2.1.275. It isn't a statement about your account. What a flag value here can and cannot tell you

See this entry in the whole of v2.1.275 →