tengu_quartz_heron
A Claude Code feature flag, read out of the shipped bundle.
It was in the build from v2.1.152 and was gone by v2.1.198.
Default false. Picks the model for the built-in Explore agent: when false it uses haiku; when true it uses inherit (the parent's model), except on the first-party API when the parent model name contains none of haiku, sonnet or opus, where it uses opus.
Not Anthropic's. Written by Claude Opus 5.5 from reading the v2.1.197 bundle, and it can be wrong.
First seen v2.1.152
Last seen v2.1.197 30 Jun 2026, gone by v2.1.198
Builds37 / 149on this box, as of v2.1.308
Written about — no changelog entry names it
v2.1.152in the build not in the build never minedv2.1.308
In the changelogs
0
No changelog entry here has ever named it. That is a statement about what has been written, not about the name: it has been in the build since v2.1.152 without anybody writing a line about it.
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
2
BuildsHow manyDatesReading
v2.1.152 – v2.1.19737 builds → 30 Jun 2026 ◆in the build
v2.1.198 – v2.1.30899 builds1 Jul 2026 → 22 Oct 2026 ○not in the build
Build by build
136
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
v2.1.152·addedverdict: added · default bool:false
v2.1.153·presentverdict: present · default bool:false
v2.1.154·presentverdict: present · default bool:false
v2.1.156·presentverdict: present · default bool:false
v2.1.157·presentverdict: present · default bool:false
v2.1.158·presentverdict: present · default bool:false
v2.1.159·presentverdict: present · default bool:false
v2.1.160·presentverdict: present · default bool:false
v2.1.161·presentverdict: present · default bool:false
v2.1.162·presentverdict: present · default bool:false
v2.1.1634 Jun 2026·presentverdict: present · default bool:false
v2.1.1655 Jun 2026·presentverdict: present · default bool:false
v2.1.1665 Jun 2026·presentverdict: present · default bool:false
v2.1.1676 Jun 2026·presentverdict: present · default bool:false
v2.1.1686 Jun 2026·presentverdict: present · default bool:false
v2.1.1698 Jun 2026·presentverdict: present · default bool:false
v2.1.1709 Jun 2026·presentverdict: present · default bool:false
v2.1.17210 Jun 2026·presentverdict: present · default bool:false
v2.1.17311 Jun 2026·presentverdict: present · default bool:false
v2.1.17411 Jun 2026·presentverdict: present · default bool:false
v2.1.17512 Jun 2026·presentverdict: present · default bool:false
v2.1.17612 Jun 2026·presentverdict: present · default bool:false
v2.1.17713 Jun 2026·presentverdict: present · default bool:false
v2.1.17815 Jun 2026·presentverdict: present · default bool:false
v2.1.17916 Jun 2026·presentverdict: present · default bool:false
v2.1.18117 Jun 2026·presentverdict: present · default bool:false
v2.1.18218 Jun 2026·presentverdict: present · default bool:false
v2.1.18319 Jun 2026·presentverdict: present · default bool:false
v2.1.18520 Jun 2026·presentverdict: present · default bool:false
v2.1.18622 Jun 2026·presentverdict: present · default bool:false
v2.1.18723 Jun 2026·presentverdict: present · default bool:false
v2.1.19024 Jun 2026·presentverdict: present · default bool:false
v2.1.19124 Jun 2026·presentverdict: present · default bool:false
v2.1.19325 Jun 2026·presentverdict: present · default bool:false
v2.1.19526 Jun 2026·presentverdict: present · default bool:false
v2.1.19629 Jun 2026·presentverdict: present · default bool:false
v2.1.19730 Jun 2026·presentverdict: present · default bool:false
v2.1.1981 Jul 2026·removedverdict: removed
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.
