{"record":{"id":"4c5befb840b5d55d","repo":"openai/codex","slug":"mcp-authorization-server-does-not-advertise-cimd-w","errorCode":null,"errorMessage":"MCP authorization server does not advertise CIMD with token endpoint auth method `none`","messagePattern":"MCP authorization server does not advertise CIMD with token endpoint auth method `none`","errorType":"exception","errorClass":"anyhow::Error","httpStatus":null,"severity":"error","filePath":"codex-rs/rmcp-client/src/oauth_client_registration.rs","lineNumber":79,"sourceCode":"            parsed_redirect_uri.host_str(),\n            Some(\"127.0.0.1\" | \"localhost\")\n        )\n        && parsed_redirect_uri.port().is_some_and(|port| port > 0)\n        && parsed_redirect_uri.path() == format!(\"/callback/{callback_id}\")\n        && parsed_redirect_uri.query().is_none()\n        && parsed_redirect_uri.fragment().is_none()\n        && parsed_redirect_uri.username().is_empty()\n        && parsed_redirect_uri.password().is_none();\n    // MCP 2026-07-28 priority: pre-registered clients never reach this path; offer\n    // advertised CIMD here and otherwise let rmcp fall back to DCR.\n    // https://modelcontextprotocol.io/specification/2026-07-28/basic/authorization/client-registration\n    let offer_cimd = match client_registration {\n        McpOAuthClientRegistration::Auto => {\n            cimd_advertised && native_redirect_supported && public_client_auth_supported\n        }\n        McpOAuthClientRegistration::Cimd => {\n            if !cimd_advertised || !public_client_auth_supported {\n                bail!(\n                    \"MCP authorization server does not advertise CIMD with token endpoint auth method `none`\"\n                );\n            }\n            if !native_redirect_supported {\n                bail!(\n                    \"MCP OAuth CIMD requires an ephemeral loopback callback at `/callback/{callback_id}`\"\n                );\n            }\n            true\n        }\n        McpOAuthClientRegistration::Dcr => false,\n    };\n\n    auth_manager.set_metadata(metadata);\n    let mut request = AuthorizationRequest::new(redirect_uri)\n        .with_scopes(scopes.iter().copied())\n        .with_client_name(\"Codex\");\n    if offer_cimd {","sourceCodeStart":61,"sourceCodeEnd":97,"githubUrl":"https://github.com/openai/codex/blob/339751715c64496cb86246bfb3935f40e309dd3d/codex-rs/rmcp-client/src/oauth_client_registration.rs#L61-L97","documentation":"Error \"MCP authorization server does not advertise CIMD with token endpoint auth method `none`\" thrown in openai/codex.","triggerScenarios":"Thrown at codex-rs/rmcp-client/src/oauth_client_registration.rs:79 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":[],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"339751715c64496cb86246bfb3935f40e309dd3d","analyzedAt":"2026-08-25T05:35:09.876Z","schemaVersion":2},"datasetVersion":"2026-08-25T06:17:31.827Z"}