Source Intelligence

DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

All of v2.1.221 Home All releases olderv2.1.220 v2.1.222newer

Cache-backed MCP servers report as pending rather than unknown

Under the hood
Useful2 Signal0
MCP

MCP servers restored from the discovery cache now report a proper 'pending' status instead of unknown.

Feature flag
tengu_mcp_discovery_cache Not enough to say

Nothing here resolved what this flag was doing on this version, so nothing here should be read as on or off.

This account: no value returned · anonymous baseline: no value returned · compiled default in v2.1.221: 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 v2.1.221. It isn't a statement about your account. What a flag value here can and cannot tell you

What

Servers whose tools came from the discovery cache now have a defined status in the serialized MCP server state used by the SDK and status consumers.

Details
  • The serializer exposing name, status, config, scope and serverInfo maps the internal cached client type to the wire status pending.
  • serverInfo is now reported for cached clients as well as connected ones.
  • Only reachable when the discovery cache actually produces a cached client, which is governed by tengu_mcp_discovery_cache.
Evidence

return e === "cached" ? "pending" : e;

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

See this entry in the whole of v2.1.221 →