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.
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.
First seen v2.1.138 9 May 2026
Last seen v2.1.309 22 Oct 2026
Builds150 / 150on this box, as of v2.1.309
Written about v2.1.124 first named in a changelog, 30 Apr 2026
v2.1.138in the build not in the build never minedv2.1.309
In the changelogs
1
Releases whose published page names tengu_kairos_brief_stop_hook_text.
gate cited by this entry, found in this entry's text
Gate readings
0
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.
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
v2.1.138 – v2.1.309150 builds9 May 2026 → 22 Oct 2026 ◆in the build
Build by build
150
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
v2.1.1389 May 2026·presentverdict: present · default string
v2.1.13911 May 2026·presentverdict: present · default string
v2.1.14012 May 2026·presentverdict: present · default string
v2.1.2871 Oct 2026·presentverdict: present · default string
v2.1.2882 Oct 2026·presentverdict: present · default string
v2.1.2893 Oct 2026·presentverdict: present · default string
v2.1.2905 Oct 2026·presentverdict: present · default string
v2.1.2916 Oct 2026·presentverdict: present · default string
v2.1.2926 Oct 2026·presentverdict: present · default string
v2.1.2937 Oct 2026·presentverdict: present · default string
v2.1.2948 Oct 2026·presentverdict: present · default string
v2.1.2958 Oct 2026·presentverdict: present · default string
v2.1.2969 Oct 2026·presentverdict: present · default string
v2.1.29914 Oct 2026·presentverdict: present · default string
v2.1.30014 Oct 2026·presentverdict: present · default string
v2.1.30115 Oct 2026·presentverdict: present · default string
v2.1.30216 Oct 2026·presentverdict: present · default string
v2.1.30318 Oct 2026·presentverdict: present · default string
v2.1.30419 Oct 2026·presentverdict: present · default string
v2.1.30520 Oct 2026·presentverdict: present · default string
v2.1.30621 Oct 2026·presentverdict: present · default string
v2.1.30721 Oct 2026·presentverdict: present · default string
v2.1.30822 Oct 2026·presentverdict: present · default string
v2.1.30922 Oct 2026·presentverdict: present · default string
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.
