{"record":{"id":"f495da70e0bd8eea","repo":"googleapis/mcp-toolbox","slug":"invalid-source-for-q-tool-source-q-is-not-a-com-f495da","errorCode":null,"errorMessage":"invalid source for %q tool: source %q is not a compatible type","messagePattern":"invalid source for %q tool: source %q is not a compatible type","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"internal/tools/looker/lookergetconnectiondatabases/lookergetconnectiondatabases.go","lineNumber":106,"sourceCode":"// validate interface\nvar _ tools.Tool = Tool{}\n\ntype Tool struct {\n\ttools.BaseTool[Config]\n}\n\nfunc (t Tool) GetSourceName() string {\n\treturn t.Cfg.Source\n}\n\nfunc (t Tool) ToConfig() tools.ToolConfig {\n\treturn t.Cfg\n}\n\nfunc (t Tool) ValidateSource(source sources.Source) error {\n\t_, ok := source.(compatibleSource)\n\tif !ok {\n\t\treturn fmt.Errorf(\"invalid source for %q tool: source %q is not a compatible type\", t.Cfg.Type, t.Cfg.Source)\n\t}\n\treturn nil\n}\n\nfunc (t Tool) Invoke(ctx context.Context, s sources.Source, params parameters.ParamValues, accessToken tools.AccessToken) (any, util.ToolboxError) {\n\tsource, ok := s.(compatibleSource)\n\tif !ok {\n\t\treturn nil, util.NewClientServerError(\"source used is not compatible with the tool\", http.StatusInternalServerError, nil)\n\t}\n\tmapParams := params.AsMap()\n\tconn, ok := mapParams[\"conn\"].(string)\n\tif !ok {\n\t\treturn nil, util.NewAgentError(fmt.Sprintf(\"'conn' must be a string, got %T\", mapParams[\"conn\"]), nil)\n\t}\n\n\tsdk, err := source.GetLookerSDK(ctx, string(accessToken))\n\tif err != nil {\n\t\treturn nil, util.NewClientServerError(\"error getting sdk\", http.StatusInternalServerError, err)","sourceCodeStart":88,"sourceCodeEnd":124,"githubUrl":"https://github.com/googleapis/mcp-toolbox/blob/8cc6e09de2ad7b8bffc77751799585a1401a48eb/internal/tools/looker/lookergetconnectiondatabases/lookergetconnectiondatabases.go#L88-L124","documentation":"ValidateSource performs a Go type assertion of the configured source against the tool's compatibleSource interface (Looker API access). The error fires at server startup when the tool's 'source' references a source kind (e.g. postgres, cloudstorage) that does not implement the Looker-compatible interface, meaning the tool/source pairing in tools.yaml is invalid.","triggerScenarios":"Thrown at internal/tools/looker/lookergetconnectiondatabases/lookergetconnectiondatabases.go:106 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Set the tool's 'source' field to the name of a Looker source defined in the sources section of tools.yaml","Verify the source kind is 'looker' and not another database/source type","Check for typos in the source name that silently matched a different source"],"exampleFix":null,"handlingStrategy":"validation","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"8cc6e09de2ad7b8bffc77751799585a1401a48eb","analyzedAt":"2026-09-05T01:10:36.887Z","contentChangedAt":"2026-09-05T01:10:36.887Z","schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}