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.
Default false. Chooses the endpoint for the list of official MCP server URLs: when on, /api/directory/servers (up to 500 per page, remote servers only); when off, the legacy /mcp-registry/v0/servers (version=latest, 100 per page). Either way at most 20 pages are fetched.
Not Anthropic's. Written by Claude Opus 5.5 from reading the v2.1.286 bundle, and it can be wrong.
First seen v2.1.138 9 May 2026
Last seen v2.1.308 22 Oct 2026
Builds149 / 149on this box, as of v2.1.308
Written about v2.1.101 first named in a changelog, 10 Apr 2026
v2.1.138in the build not in the build never minedv2.1.308
In the changelogs
1
Releases whose published page names tengu_mcp_directory_bff.
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
1
The earliest release whose published evidence quoted tengu_mcp_directory_bff was v2.1.101, 10 Apr 2026. That is the oldest release this project wrote about it, so it is a floor on the name's age and not the release that introduced it. It is not a presence reading: which builds carried the name is the table below.
v2.1.138 – v2.1.308149 builds9 May 2026 → 22 Oct 2026 ◆in the build
Build by build
149
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 bool:false
v2.1.13911 May 2026·presentverdict: present · default bool:false
v2.1.14012 May 2026·presentverdict: present · default bool:false
v2.1.2871 Oct 2026·presentverdict: present · default bool:false
v2.1.2882 Oct 2026·presentverdict: present · default bool:false
v2.1.2893 Oct 2026·presentverdict: present · default bool:false
v2.1.2905 Oct 2026·presentverdict: present · default bool:false
v2.1.2916 Oct 2026·presentverdict: present · default bool:false
v2.1.2926 Oct 2026·presentverdict: present · default bool:false
v2.1.2937 Oct 2026·presentverdict: present · default bool:false
v2.1.2948 Oct 2026·presentverdict: present · default bool:false
v2.1.2958 Oct 2026·presentverdict: present · default bool:false
v2.1.2969 Oct 2026·presentverdict: present · default bool:false
v2.1.29914 Oct 2026·presentverdict: present · default bool:false
v2.1.30014 Oct 2026·presentverdict: present · default bool:false
v2.1.30115 Oct 2026·presentverdict: present · default bool:false
v2.1.30216 Oct 2026·presentverdict: present · default bool:false
v2.1.30318 Oct 2026·presentverdict: present · default bool:false
v2.1.30419 Oct 2026·presentverdict: present · default bool:false
v2.1.30520 Oct 2026·presentverdict: present · default bool:false
v2.1.30621 Oct 2026·presentverdict: present · default bool:false
v2.1.30721 Oct 2026·presentverdict: present · default bool:false
v2.1.30822 Oct 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.
