{"version":"2.1.248","anchor":"mcp-capability-lists-are-fetched-once-per-server","canonical_anchor":"mcp-capability-lists-are-fetched-once-per-server","heading":"MCP capability lists are fetched once per server","tier":"notice","area":"MCP","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.248\/e\/mcp-capability-lists-are-fetched-once-per-server","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.248","markdown":"### MCP capability lists are fetched once per server\n\nMCP tool and resource listings are fetched once per server, with classified failures.\n\n**What**\n\nTool, resource, prompt and resource-template listings are now cached per server rather than re-fetched, and failures are classified instead of being opaque.\n\n**Details**\n\n- Caching is keyed on server name plus config, with the cache entry deleted on failure so the next attempt retries.\n- Failures set needs-auth and bearer-rejected flags on the client and map JSON-RPC codes to reasons such as `mcp_list_tools_timeout`.\n\n**Evidence**\n\n`tools\/list 401\/403 on claude.ai proxy \\u2014 flagging needs-auth`\n\n- Area: MCP\n- Tier: You'll notice\n- Useful: 3\/5\n- Signal: 2\/5"}