{"record":{"id":"c4b5fb418a71a097","repo":"googleapis/mcp-toolbox","slug":"unable-to-unmarshal-group-s","errorCode":null,"errorMessage":"unable to unmarshal group: %s","messagePattern":"unable to unmarshal group: (.+?)","errorType":"validation","errorClass":null,"httpStatus":null,"severity":"error","filePath":"internal/server/config.go","lineNumber":570,"sourceCode":"\tdec, err := util.NewStrictDecoder(justTools)\n\tif err != nil {\n\t\treturn toolsetConfig, fmt.Errorf(\"error creating decoder: %s\", err)\n\t}\n\tvar raw map[string][]string\n\tif err := dec.DecodeContext(ctx, &raw); err != nil {\n\t\treturn toolsetConfig, fmt.Errorf(\"unable to unmarshal tools: %s\", err)\n\t}\n\treturn tools.ToolsetConfig{Name: name, ToolNames: raw[\"tools\"]}, nil\n}\n\nfunc UnmarshalYAMLGroupConfig(ctx context.Context, name string, r map[string]any) (group.GroupConfig, error) {\n\tdec, err := util.NewStrictDecoder(r)\n\tif err != nil {\n\t\treturn group.GroupConfig{}, fmt.Errorf(\"error creating decoder: %s\", err)\n\t}\n\tgc := group.GroupConfig{Name: name}\n\tif err := dec.DecodeContext(ctx, &gc); err != nil {\n\t\treturn group.GroupConfig{}, fmt.Errorf(\"unable to unmarshal group: %s\", err)\n\t}\n\t// The default (nameless) group always contains all configured tools and\n\t// prompts, so it may only set a description.\n\tif name == \"\" && (len(gc.ToolNames) > 0 || len(gc.PromptNames) > 0) {\n\t\treturn group.GroupConfig{}, fmt.Errorf(\"the default (nameless) group cannot declare 'tools' or 'prompts'; it always contains all configured tools and prompts\")\n\t}\n\treturn gc, nil\n}\n\nfunc UnmarshalYAMLPromptConfig(ctx context.Context, name string, r map[string]any) (prompts.PromptConfig, error) {\n\t// Look for the 'type' field. If it's not present, typeStr will be an\n\t// empty string, which prompts.DecodeConfig will correctly default to \"custom\".\n\tvar resourceType string\n\tif typeVal, ok := r[\"type\"]; ok {\n\t\tvar isString bool\n\t\tresourceType, isString = typeVal.(string)\n\t\tif !isString {\n\t\t\treturn nil, fmt.Errorf(\"invalid 'type' field for prompt %q (must be a string)\", name)","sourceCodeStart":552,"sourceCodeEnd":588,"githubUrl":"https://github.com/googleapis/mcp-toolbox/blob/8cc6e09de2ad7b8bffc77751799585a1401a48eb/internal/server/config.go#L552-L588","documentation":"Error \"unable to unmarshal group: %s\" thrown in googleapis/mcp-toolbox.","triggerScenarios":"Thrown at internal/server/config.go:570 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":"8cc6e09de2ad7b8bffc77751799585a1401a48eb","analyzedAt":"2026-09-05T01:10:36.887Z","contentChangedAt":"2026-09-05T01:10:36.887Z","schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}