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DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

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Claude Code v2.1.217

Four New Unnamed Feature Flags [In Development]

Feature flag
tengu_bison_cairn 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 v2.1.217: 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 v2.1.217. It isn't a statement about your account. What a flag value here can and cannot tell you

Four new feature flag constants have been added without any observable user-facing behavior yet:

  • tengu_amber_astrolabe (also: CLAUDE_CODE_AMBER_ASTROLABE env var)
  • tengu_bison_cairn (also: CLAUDE_CODE_BISON_CAIRN env var)
  • tengu_larch_cistern (also: CLAUDE_CODE_LARCH_CISTERN env var)
  • tengu_alder_wicket (also: CLAUDE_CODE_ALDER_WICKET env var)

These are infrastructure additions that will be wired to behavior in a future release.

Details
  • tengu_amber_astrolabe / CLAUDE_CODE_AMBER_ASTROLABE: accessor ekc() is checked in Fa_() alongside the existing max/autonomous mode gate (VMe(e)); when true, the autonomy system prompt section is injected even outside max mode, instructing Claude to proceed with reversible actions without asking "Want me to…?" permission questions and to stop only for destructive actions or genuine scope changes
  • tengu_bison_cairn / CLAUDE_CODE_BISON_CAIRN: accessor tkc() gates the "delivering_work_max" system prompt slot (el_); when true, a # Delivering work instruction block is added telling Claude to: act on what is in the request rather than speculation; deliver complete work under stated assumptions; explicitly report blocked sub-tasks; carry mid-task questions to the end of a turn that also delivers progress (rather than blocking); and treat user reaffirmation as a final decision to proceed
  • tengu_larch_cistern / CLAUDE_CODE_LARCH_CISTERN: accessor rkc() gates the "overcorrection" system prompt slot (tl_); when true, a # Corrections instruction block is added telling Claude to: only correct errors that would change the user's code, conclusions, or decisions; state corrections plainly and continue without apology, preamble, or rumination; not treat a follow-up question as a signal of prior error
  • tengu_alder_wicket / CLAUDE_CODE_ALDER_WICKET: accessor nkc() gates the "scope_fidelity" system prompt slot (rl_); when true, a second # Delivering work instruction block (a tighter variant) is added telling Claude to: interpret ambiguity as a careful colleague would; briefly state concerns then proceed as asked; finish the whole task not just the easy parts; stop short of actions clearly beyond what the request implies
  • All four use the shared helper gYt(envVar, flagName) which returns true if the env var is set, managed settings has the flag true, or Ke() returns true for the flag name
Evidence

Accessor functions and system prompt slots (search for "ekc()" near Fa_() for amber_astrolabe; "delivering_work_max" for bison_cairn; "overcorrection" for larch_cistern; "scope_fidelity" for alder_wicket)

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

See this entry in the whole of v2.1.217 →