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Sweep 28 Aug 2026 · 00:00Z Build v2.1.250 478 read Stable v2.1.236 Latest v2.1.250 Next v2.1.250 Feeds RSS JSON llms.txt

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.

Reference / Feature flags

tengu_slate_harrier

A Claude Code feature flag, read out of the shipped bundle. It was in the build from v2.1.138 and was gone by v2.1.223.

What it is

Claude no longer spends up to a minute investigating before asking you a clarifying question.

Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.223.

Presence across releases

ReleasesReadingDeclared typeDefault
2.1.245 – 2.1.250 5 releases never mined — —
2.1.223 – 2.1.243 20 releases not in the build — —
2.1.138 – 2.1.222 75 releases in the build — string

A row reading never mined is a release with no archived bundle behind it. Nothing was read out of it, so nothing here says whether the name was in it. A declared type or a default is only ever what that release's own bundle stated.

Gate readings

ReleaseResolvedThis accountAnonymousCompiled default
v2.1.223 read on another version Not enough to say no value returned no value returned not a boolean we can read
v2.1.122 read on another version Not enough to say no value returned no value returned no gate table built for this version

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.

Changelog entries naming it

  1. v2.1.223"Investigate first" system prompt experiment removed

    Claude no longer spends up to a minute investigating before asking you a clarifying question.

    gate cited by this entry

  2. v2.1.122"Investigate First" System Prompt [Gradual Rollout]

    gate cited by this entry

Documentation pages

None of Anthropic's documentation pages this site has a copy of carries this name.

Names beside it

Every feature flag in the inventory starting tengu_slate, up to twelve of them.

tengu_slate_anchorSome feature flags now stay fixed for the whole session, including a new one that is on. never mined tengu_slate_fernNo description from anybody. 2.1.172 tengu_slate_finchNo description from anybody. 2.1.138 tengu_slate_harborREPL contexts moved to a registry that releases timers even on error paths. 2.1.138 tengu_slate_harbor_experimentNo description from anybody. 2.1.138 tengu_slate_heronNo description from anybody. never mined tengu_slate_ibisExplore and plan agents are now always on unless you set the disable environment variable yourself. 2.1.217 tengu_slate_kestrelNo description from anybody. 2.1.138 tengu_slate_lanternA new --watch-artifact flag follows a claude.ai artifact for new versions and comments, but needs account access. 2.1.198 tengu_slate_lantern_emberRe-armed artifact watches could reuse an existing connection instead of starting over, but the flag is off. 2.1.236 tengu_slate_meadowNo description from anybody. 2.1.138 tengu_slate_mothNo description from anybody. 2.1.191

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.