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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_copper_lantern

A Claude Code feature flag, read out of the shipped bundle. It has been in the build since v2.1.138, including the newest one read.

What it is

Nobody has written a line about this one. It is not in any of Anthropic's reference tables and no changelog entry here carries a description of it. It is in the build, which is the whole of what this page can claim.

Presence across releases

ReleasesReadingDeclared typeDefault
2.1.245 – 2.1.250 5 releases never mined — —
2.1.138 – 2.1.243 95 releases in the build — bool:false

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

No release here has a gate table behind it for this flag. Most published releases have none at all: the readings exist only for versions the pipeline captured flag state on.

Changelog entries naming it

  1. v2.1.63Opus 4.6 Launch Promo Removed

    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_copper, up to twelve of them.

tengu_copper_foxForked subagents are on by default in interactive sessions; set CLAUDE_CODE_FORK_SUBAGENT to false to opt out. 2.1.138 tengu_copper_kestrelNo description from anybody. 2.1.234 tengu_copper_thistleThe status line always calls MCP background work a "task" instead of sometimes saying "job". 2.1.161

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.