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Sweep 25 Sep 2026 · 19:33Z Build v2.1.283 504 read Stable v2.1.274 Latest v2.1.283 Next v2.1.283 Feeds RSS JSON llms.txt llms-full.txt Unofficial

tengu_binary_balloon

flag in the build JSON

A Claude Code feature flag, read out of the shipped bundle. It has been in the build since v2.1.281, including the newest one read.

Remote sessions can send tool descriptions straight from a recorded snapshot instead of rebuilding them, behind tengu_binary_balloon

Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.281.

First seen v2.1.281 23 Sep 2026
Last seen v2.1.283 25 Sep 2026
Builds3 / 126on this box, as of v2.1.283
Written about v2.1.281 first named in a changelog, 23 Sep 2026
v2.1.281in the build not in the build never minedv2.1.283

In the changelogs

1

Releases whose published page names tengu_binary_balloon.

  1. v2.1.281
    Tool schemas can be sent straight from the recorded prompt snapshot (tengu_binary_balloon, off by default)

    Remote sessions can send tool descriptions straight from a recorded snapshot instead of rebuilding them, behind tengu_binary_balloon

    gate cited by this entry, found in this entry's text

Gate readings

1
ReleaseResolvedThis accountAnonymousCompiled default
v2.1.281 read on another version Off in both readings off off off

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.

Flag server, over time

2
Read asReadingFromUntilVersion installed
this account off 2026-09-23T15:00:07Z 2026-09-28T06:45:05Z v2.1.280 to v2.1.283
anonymous off 2026-09-23T14:40:05Z 2026-09-28T06:45:05Z v2.1.280 to v2.1.283

One row per unbroken stretch of one reading, newest first, from snapshots taken every twenty-five minutes or so. No longer carried is not off: it means the flag server stopped returning the gate at all, which is what a retired experiment looks like. The version column is what was installed when the reading was taken, not what caused it.

First cited

0

No release's published evidence quotes this name. The ledger indexes the Evidence lines of every changelog on this site, so this says nobody here has ever quoted it; it says nothing about how old the name is.

Presence across releases

1
BuildsHow manyDatesReading
v2.1.281 – v2.1.2833 builds23 Sep 2026 → 25 Sep 2026 ◆in the build

Build by build

3

One row per release since the first build this name was read out of. Absent means the build was read and the name was not in it, never mined means no bundle for that release was ever archived, and a declared type or a default is only ever what that release's own bundle stated.

BuildDateStateThe record behind it
v2.1.28123 Sep 2026·addedverdict: added · default bool:false
v2.1.28224 Sep 2026·presentverdict: present · default bool:false
v2.1.28325 Sep 2026·presentverdict: present · default bool:false

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.

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