{"record":{"id":"5f28165ae1b09c79","repo":"googleapis/mcp-toolbox","slug":"description-is-required-for-tool-q-5f2816","errorCode":null,"errorMessage":"description is required for tool %q","messagePattern":"description is required for tool %q","errorType":"validation","errorClass":null,"httpStatus":null,"severity":"error","filePath":"internal/tools/looker/lookerdevmode/lookerdevmode.go","lineNumber":70,"sourceCode":"\tGetLookerSDK(context.Context, string) (*v4.LookerSDK, error)\n}\n\ntype Config struct {\n\ttools.ConfigBase `yaml:\",inline\"`\n\tType             string                 `yaml:\"type\" validate:\"required\"`\n\tSource           string                 `yaml:\"source\" validate:\"required\"`\n\tAnnotations      *tools.ToolAnnotations `yaml:\"annotations,omitempty\"`\n}\n\nvar _ tools.ToolConfig = Config{}\n\nfunc (cfg Config) ToolConfigType() string {\n\treturn resourceType\n}\n\nfunc (cfg Config) Initialize(context.Context) (tools.Tool, error) {\n\tif cfg.Description == \"\" {\n\t\treturn nil, fmt.Errorf(\"description is required for tool %q\", cfg.Name)\n\t}\n\n\tdevModeParameter := parameters.NewBooleanParameter(\"devMode\", \"Whether to set Dev Mode.\", parameters.WithBooleanDefault(true))\n\tparams := parameters.Parameters{devModeParameter}\n\n\treturn Tool{\n\t\tBaseTool: tools.NewBaseTool(\n\t\t\tcfg,\n\t\t\ttools.GetAnnotationsOrDefault(cfg.Annotations, tools.NewReadOnlyAnnotations),\n\t\t\ttools.Manifest{Description: cfg.Description, Parameters: params.Manifest(), AuthRequired: cfg.AuthRequired},\n\t\t\tparams,\n\t\t),\n\t}, nil\n}\n\nvar _ tools.Tool = Tool{}\n\ntype Tool struct {","sourceCodeStart":52,"sourceCodeEnd":88,"githubUrl":"https://github.com/googleapis/mcp-toolbox/blob/8cc6e09de2ad7b8bffc77751799585a1401a48eb/internal/tools/looker/lookerdevmode/lookerdevmode.go#L52-L88","documentation":"Looker tool configs require a non-empty description because it is published to MCP clients as the tool's description. Initialize validates this up front and fails when Config.Description is empty so undescribed tools never get registered.","triggerScenarios":"A lookerdevmode tool entry in the tools YAML missing the description field, then Initialize is called during config load.","commonSituations":"Hand-written configs omitting description; building Config structs in Go tests without Description; minimal copy-pasted tool definitions.","solutions":["Add a description to the lookerdevmode tool config","Set Description programmatically before Initialize","Validate YAML against the tool's schema before loading"],"exampleFix":"// before\n- name: set-dev-mode\n  source: my-looker\n// after\n- name: set-dev-mode\n  source: my-looker\n  description: Toggles Looker Dev Mode","handlingStrategy":"validation","validationCode":"if strings.TrimSpace(cfg.Description) == \"\" { return errors.New(\"looker tool config requires a description\") }","typeGuard":null,"tryCatchPattern":"if _, err := cfg.Initialize(ctx); err != nil { return fmt.Errorf(\"invalid tool config: %w\", err) }","preventionTips":["Always set description for every tool definition","Schema-validate tool YAML before server start","Copy from complete example configs, not minimal snippets"],"tags":["go","looker","config","missing-field"],"backgroundTag":"missing-required-config-field","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"}