tengu_mcp_discovery_cache
A Claude Code feature flag, read out of the shipped bundle. It was in the build from v2.1.221 and was gone by v2.1.238.
The /mcp view now counts cached servers separately so you can tell them from live connections.
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.221.
In the changelogs
6Releases whose published page names tengu_mcp_discovery_cache.
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v2.1.221
/mcp status surfaces cached servers
The /mcp view now counts cached servers separately so you can tell them from live connections.
gate cited by this entry, found in this entry's text
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v2.1.221
MCP servers can start from a discovery cache and connect lazily
Startup no longer dials cached HTTP or SSE MCP servers; they restore from cache and connect on first use.
gate cited by this entry, found in this entry's text
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v2.1.221
MCP servers can start in a new "cached" state instead of blocking on connect
MCP servers with a saved cache now show tools instantly and only connect when you first use them.
gate cited by this entry, found in this entry's text
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v2.1.221
Discovery-cache misses are classified in telemetry
MCP tool discovery now logs whether the cache was used, and servers with skills or channels deliberately skip it.
gate cited by this entry, found in this entry's text
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v2.1.221
MCP task restore dials lazily-cached servers instead of giving up
Resuming a long-running MCP task after a restart now reconnects cached servers instead of failing.
gate cited by this entry, found in this entry's text
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v2.1.221
Cache-backed MCP servers report as pending rather than unknown
MCP servers restored from the discovery cache now report a proper 'pending' status instead of unknown.
gate cited by this entry, found in this entry's text
Gate readings
2| Release | Resolved | This account | Anonymous | Compiled default |
|---|---|---|---|---|
| v2.1.238 | Not enough to say | no value returned | no value returned | not a boolean we can read |
| v2.1.221 read on another version | Not enough to say | no value returned | no value returned | on |
Two arms, because they disagree: this account is the one account this site reads and anonymous is a baseline with no identity attached. A reading says nothing about your account, and off cannot rule out a rollout both readings sit outside of. What these readings can and cannot show.
First cited
1The earliest release whose published evidence quoted tengu_mcp_discovery_cache was v2.1.221, 3 Aug 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.
Presence across releases
2Build by build
77One 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.
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.