{"name":"MCP_DISCOVERY_CACHE","slug":"mcp-discovery-cache","family":"env","title":"Environment variables","noun":"environment variable","description":"Startup no longer dials cached HTTP or SSE MCP servers; they restore from cache and connect on first use.","description_source":"entry","described_by":{"version":"2.1.221","anchor":"mcp-servers-can-start-from-a-discovery-cache-and-connect-laz"},"presence":{"first_seen":"2.1.217","removed_in":null,"in_current_build":true,"newest_mined":"2.1.309","builds":81,"mined_builds":150,"first_cited":{"version":"2.1.238","released_at":"2026-08-20 18:01:54","spans":2}},"aliases":[],"entries":[{"version":"2.1.285","anchor":"mcp-discovery-cache-for-ccr-dynamic-http-servers","heading":"MCP discovery cache now limited to dynamic toolbox servers in cloud sessions","line":"With `MCP_DISCOVERY_CACHE` on, only dynamic toolbox HTTP servers in cloud sessions that send two identifying headers can use the cache","released_at":"2026-09-29 17:32:09","reason":"found in this entry's text"},{"version":"2.1.282","anchor":"mcp-discovery-cache-is-forced-off-in-diskless-launches","heading":"MCP discovery cache stays off when Claude Code runs without a disk","line":"In a diskless launch, Claude Code now keeps the MCP discovery cache off for the whole session regardless of other settings","released_at":"2026-09-24 15:56:22","reason":"found in this entry's text, named in this entry"},{"version":"2.1.238","anchor":"the-mcp-discovery-cache-is-now-off-unless-explicitly-turned-","heading":"The MCP discovery cache is now off unless explicitly turned on","line":"The MCP discovery cache flipped from on-by-default to off unless the server or you enable it.","released_at":"2026-08-20 18:01:54","reason":"named in this entry, found in this entry's text"},{"version":"2.1.238","anchor":"mcp-work-aborts-when-the-signed-in-account-changes-mid-fligh","heading":"MCP work aborts when the signed-in account changes mid-flight","line":"Switching accounts would cancel in-flight MCP work instead of finishing it under the new identity, but it's dark.","released_at":"2026-08-20 18:01:54","reason":"found in this entry's text"},{"version":"2.1.238","anchor":"mcp-servers-can-connect-lazily-from-a-cached-entry","heading":"MCP servers can connect lazily from a cached entry","line":"Tool calls to a remembered MCP server could dial it on demand, but the cache behind it is off.","released_at":"2026-08-20 18:01:54","reason":"named in this entry, found in this entry's text"},{"version":"2.1.232","anchor":"mcp-discovery-cache-and-skills-fetcher-built-on-first-use","heading":"MCP discovery cache and skills fetcher built on first use","line":"The MCP discovery cache and skills fetcher are built on first use rather than at load.","released_at":"2026-08-13 21:30:53","reason":"found in this entry's text"},{"version":"2.1.221","anchor":"mcp-servers-can-start-from-a-discovery-cache-and-connect-laz","heading":"MCP servers can start from a discovery cache and connect lazily","line":"Startup no longer dials cached HTTP or SSE MCP servers; they restore from cache and connect on first use.","released_at":"2026-08-03 22:16:25","reason":"named in this entry, found in this entry's text"},{"version":"2.1.221","anchor":"mcp-servers-can-start-in-a-new-cached-state-instead-of-block","heading":"MCP servers can start in a new \"cached\" state instead of blocking on connect","line":"MCP servers with a saved cache now show tools instantly and only connect when you first use them.","released_at":"2026-08-03 22:16:25","reason":"named in this entry, found in this entry's text"}],"entries_total":8,"docs":[{"source":"claude-code","path":"changelog","title":"Claude Code changelog","documented":false},{"source":"claude-code","path":"mcp","title":"Connect Claude Code to tools via MCP","documented":false}],"docs_total":2,"gates":[],"related":[{"name":"MCP_DISCOVERY_CACHE_MAX_STALE_S","slug":"mcp-discovery-cache-max-stale-s","description":"Cached MCP server discovery is dropped after repeated connection failures instead of only on age."},{"name":"MCP_DISCOVERY_CACHE_STRIKES","slug":"mcp-discovery-cache-strikes","description":"Cached MCP server discovery is dropped after repeated connection failures instead of only on age."},{"name":"MCP_DISCOVERY_CACHE_TTL_S","slug":"mcp-discovery-cache-ttl-s","description":"Cached MCP server discovery is dropped after repeated connection failures instead of only on age."}],"url":"https:\/\/changelogs.core-directive.com\/reference\/env\/mcp-discovery-cache","family_url":"https:\/\/changelogs.core-directive.com\/reference\/env.json"}