tengu_mcp_discovery_source
A Claude Code feature flag, read out of the shipped bundle. No mined inventory carries it: everything below comes from what this site has written about it.
What it is
Startup no longer dials cached HTTP or SSE MCP servers; they restore from cache and connect on first use.
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.221.
Presence across releases
The miner has never read a build containing this name. It is here because a changelog entry of ours names it, which is evidence that it existed and not evidence of which releases carried it. The inventory starts at v2.1.138 and everything older than that was never mined.
Gate readings
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.
Changelog entries naming it
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v2.1.221MCP 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
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v2.1.221MCP 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
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v2.1.221Discovery-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
Documentation pages
None of Anthropic's documentation pages this site has a copy of carries this name.
Names beside it
Every feature flag in the inventory starting tengu_mcp_discovery, up to twelve of them.
tengu_mcp_discovery_cacheThe /mcp view now counts cached servers separately so you can tell them from live connections. 2.1.221
tengu_mcp_discovery_cache_enableCalling a tool on a disabled MCP server would tell you to re-enable it, but that path is off. 2.1.238
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.