{"record":{"id":"b551918f34fdcb10","repo":"googleapis/mcp-toolbox","slug":"parameter-is-missing-type-field","errorCode":null,"errorMessage":"parameter is missing 'type' field","messagePattern":"parameter is missing 'type' field","errorType":"validation","errorClass":null,"httpStatus":null,"severity":"error","filePath":"internal/util/parameters/parameters.go","lineNumber":393,"sourceCode":"\t\t\treturn err\n\t\t}\n\t\t(*c) = append((*c), p)\n\t}\n\treturn nil\n}\n\n// parseParamFromDelayedUnmarshaler is a helper function that is required to parse\n// parameters because there are multiple different types\nfunc parseParamFromDelayedUnmarshaler(ctx context.Context, u *util.DelayedUnmarshaler) (Parameter, error) {\n\tvar p map[string]any\n\terr := u.Unmarshal(&p)\n\tif err != nil {\n\t\treturn nil, fmt.Errorf(\"error parsing parameters: %w\", err)\n\t}\n\n\tt, ok := p[\"type\"]\n\tif !ok {\n\t\treturn nil, fmt.Errorf(\"parameter is missing 'type' field\")\n\t}\n\n\ttypeStr, ok := t.(string)\n\tif !ok {\n\t\treturn nil, fmt.Errorf(\"parameter 'type' field must be a string, got %T\", t)\n\t}\n\n\tparam, err := ParseParameter(ctx, p, typeStr)\n\tif err != nil {\n\t\treturn nil, err\n\t}\n\n\tif err := validateParameter(param); err != nil {\n\t\treturn nil, err\n\t}\n\n\treturn param, nil\n}","sourceCodeStart":375,"sourceCodeEnd":411,"githubUrl":"https://github.com/googleapis/mcp-toolbox/blob/8cc6e09de2ad7b8bffc77751799585a1401a48eb/internal/util/parameters/parameters.go#L375-L411","documentation":"parseParamFromDelayedUnmarshaler looks for the discriminating 'type' key in each raw parameter map. This sentinel-style guard fires during config parsing when a parameter entry in tools.yaml lacks the 'type' field entirely, so the parser cannot dispatch to the correct parameter type.","triggerScenarios":"Thrown at internal/util/parameters/parameters.go:393 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Add a 'type' field (e.g. string, int, array, map) to the offending parameter in tools.yaml","Check the parameter block indentation so the entry is parsed as a parameter map"],"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"}