tengu_polished_quill_killswitch
A Claude Code feature flag, read out of the shipped bundle.
It has been in the build since v2.1.273, including the newest one read.
Default false. In a non-interactive session, a typed slash command that matches no command is handed to the model as an unknown_command_fallback attachment carrying the name, the closest match within edit distance 2 and up to 40 model-invocable prompt command names. Setting the flag to true turns that fallback off, and the session prints Unknown command: /name instead.
Not Anthropic's. Written by Claude Opus 5.5 from reading the v2.1.286 bundle, and it can be wrong.
First seen v2.1.273 15 Sep 2026
Last seen v2.1.322 10 Nov 2026
Builds43 / 161on this box, as of v2.1.322
Written about — no changelog entry names it
v2.1.273in the build not in the build never minedv2.1.322
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 v2.1.273 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
5
BuildsHow manyDatesReading
v2.1.273 – v2.1.29421 builds15 Sep 2026 → 8 Oct 2026 ◆in the build
v2.1.2951 build8 Oct 2026 ○not in the build
v2.1.296 – v2.1.2992 builds9 Oct 2026 → 14 Oct 2026 ◆in the build
v2.1.3001 build14 Oct 2026 ○not in the build
v2.1.301 – v2.1.32220 builds15 Oct 2026 → 10 Nov 2026 ◆in the build
Build by build
45
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
v2.1.27315 Sep 2026·addedverdict: added · default unknown
v2.1.27416 Sep 2026·presentverdict: present · default unknown
v2.1.27517 Sep 2026·presentverdict: present · default unknown
v2.1.27618 Sep 2026·presentverdict: present · default unknown
v2.1.27718 Sep 2026·presentverdict: present · default unknown
v2.1.27819 Sep 2026·presentverdict: present · default unknown
v2.1.28022 Sep 2026·presentverdict: present · default unknown
v2.1.28123 Sep 2026·presentverdict: present · default unknown
v2.1.28224 Sep 2026·presentverdict: present · default unknown
v2.1.28325 Sep 2026·presentverdict: present · default unknown
v2.1.28428 Sep 2026·presentverdict: present · default unknown
v2.1.28529 Sep 2026·presentverdict: present · default unknown
v2.1.28630 Sep 2026·presentverdict: present · default unknown
v2.1.2871 Oct 2026·presentverdict: present · default unknown
v2.1.2882 Oct 2026·presentverdict: present · default unknown
v2.1.2893 Oct 2026·presentverdict: present · default unknown
v2.1.2905 Oct 2026·presentverdict: present · default unknown
v2.1.2916 Oct 2026·presentverdict: present · default unknown
v2.1.2926 Oct 2026·presentverdict: present · default unknown
v2.1.2937 Oct 2026·presentverdict: present · default unknown
v2.1.2948 Oct 2026·presentverdict: present · default unknown
v2.1.2958 Oct 2026·removedverdict: removed
v2.1.2969 Oct 2026·addedverdict: added · default unknown
v2.1.29914 Oct 2026·presentverdict: present · default unknown
v2.1.30014 Oct 2026·removedverdict: removed
v2.1.30115 Oct 2026·addedverdict: added · default unknown
v2.1.30216 Oct 2026·presentverdict: present · default unknown
v2.1.30318 Oct 2026·presentverdict: present · default unknown
v2.1.30419 Oct 2026·presentverdict: present · default unknown
v2.1.30520 Oct 2026·presentverdict: present · default unknown
v2.1.30621 Oct 2026·presentverdict: present · default unknown
v2.1.30721 Oct 2026·presentverdict: present · default unknown
v2.1.30822 Oct 2026·presentverdict: present · default unknown
v2.1.30922 Oct 2026·presentverdict: present · default unknown
v2.1.31023 Oct 2026·presentverdict: present · default unknown
v2.1.31126 Oct 2026·presentverdict: present · default unknown
v2.1.31227 Oct 2026·presentverdict: present · default unknown
v2.1.31430 Oct 2026·presentverdict: present · default unknown
v2.1.31530 Oct 2026·presentverdict: present · default unknown
v2.1.31631 Oct 2026·presentverdict: present · default unknown
v2.1.3172 Nov 2026·presentverdict: present · default unknown
v2.1.3183 Nov 2026·presentverdict: present · default unknown
v2.1.3196 Nov 2026·presentverdict: present · default unknown
v2.1.3219 Nov 2026·presentverdict: present · default unknown
v2.1.32210 Nov 2026·presentverdict: present · default unknown
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.