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 v2.1.274 ·

New gate tengu_tidy_fern controls an alternate user-message construction path

New gate tengu_tidy_fern can add an extra value into how user messages are built

TierNothing to try yethow much it should matter to you
Useful1my rating, 1 to 5
Signal2worth watching, 1 to 5
AreaElsewherewhat it touches
KindIn Developmentin v2.1.274,
Nothing to try yet No documentation found

New gate tengu_tidy_fern can add an extra value into how user messages are built

What

A new internal flag, tengu_tidy_fern, controls whether an extra value is computed and passed along when Claude Code builds a user message for tool use. Previously this value was always left empty; now, when the flag is on, it is computed via a new function and included instead.

Why

The finding doesn't say what this extra value is used for, so it's unclear what practical difference this makes for a user.

Read from
Names in the bundletengu_tidy_fern
Feature flag
tengu_tidy_fern Not enough to say

Nothing here resolved what this flag was doing on this version, so nothing here should be read as on or off.

This account: no value returned · anonymous baseline: no value returned · compiled default in v2.1.274: on

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 v2.1.274. It isn't a statement about your account. What a flag value here can and cannot tell you

How sure we are
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubtNothing has been read about the tengu_tidy_fern gate, and what the extra computed value actually does isn't stated.
The name it cites is new in this buildNew in this build: tengu_tidy_fern

See this entry in the whole of v2.1.274 →