What
MCP servers are outside programs that give Claude extra tools. Some need you to sign in with OAuth, a standard login flow, and for that the terminal must register itself with the server as a client.
- Remembering the answer: when sign-in discovery finds that a server has no
registration_endpointand does not support client ID metadata documents, Claude Code now records the time asregistrationNotOfferedAtin its credentials store. This recording happens without any flag. - Leaving servers out: for plugins synced from claude.ai, each HTTP or SSE MCP server with no
clientId, no xaa setting and no credentials in its URL is checked against that record. If the record is less than 30 days old, the server is removed from the plugin and the debug log notes "Left out MCP server". This only happens when the flagtengu_starry_locketis on; its built-in default is false. - Checking again: if the record is older than 30 days, or dated in the future, the server is marked
redialToRelearnRegistrationinstead. It is connected again and sign-in discovery runs fresh. - Skipping discovery: a second flag,
tengu_twinkly_prism, skips MCP server discovery for claude.ai-synced plugins entirely.
Nothing has been read about tengu_starry_locket or tengu_twinkly_prism from the flag server.
Why
MCP servers from synced plugins that can never finish signing in from a terminal would stop showing up as failed sign-ins in /mcp. The 30-day window means such a server is checked again later in case it starts allowing registration.
tengu_starry_locket Off in both readingsThe flag server returned off for the account this site reads and for the anonymous baseline. A reading of off cannot rule out a rollout these two readings sit outside of.
This account: off · anonymous baseline: off · compiled default in v2.1.283: off
These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.
Read once, for one account on one subscription tier, against v2.1.283. It isn't a statement about your account. What a flag value here can and cannot tell you
A reading is one sample. Claude Code evaluates its flags remotely, so no client sees the targeting rule behind a value and this says nothing about your account.
A reading is one sample. Claude Code evaluates its flags remotely, so no client sees the targeting rule behind a value and this says nothing about your account.
The `tengu_twinkly_prism` switch also depends on another condition that is not identified.
New in this build: tengu_starry_locket