{"version":"2.1.176","anchor":"mcp-first-party-auth-error-handling","canonical_anchor":"mcp-first-party-auth-error-handling","heading":"MCP First-Party Auth Error Handling","tier":null,"area":null,"scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.176\/e\/mcp-first-party-auth-error-handling","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.176","markdown":"### MCP First-Party Auth Error Handling\n\nWhen a first-party MCP server (one using your claude.ai login) rejects the connection, Claude now emits a structured error with code `FIRST_PARTY_AUTH_REJECTED` and a more actionable message:\n\n- HTTP 403: explains the token may be missing a required scope, and suggests running `\/login`\n- HTTP 401: tells you the token may have expired, and suggests `\/login`\n\nThe new code enables better diagnostics and retry logic \u2014 if a 401 occurs after sending an access token, Claude automatically refreshes the token and retries the request once.\n\n**Evidence**\n\nFirst-party auth error (search for `\"FIRST_PARTY_AUTH_REJECTED\"` and `\"missing a scope this server needs\"`)"}