googleapis/mcp-toolbox · error

description is required for tool %q

Error message

description is required for tool %q

What it means

Configuration-time validation in Initialize: the looker-create-git-branch tool entry in tools.yaml omits its description, which Toolbox requires for the tool manifest.

Source

Thrown at internal/tools/looker/lookercreategitbranch/lookercreategitbranch.go:71

}

type Config struct {
	tools.ConfigBase `yaml:",inline"`
	Type             string                 `yaml:"type" validate:"required"`
	Source           string                 `yaml:"source" validate:"required"`
	Annotations      *tools.ToolAnnotations `yaml:"annotations,omitempty"`
}

// validate interface
var _ tools.ToolConfig = Config{}

func (cfg Config) ToolConfigType() string {
	return resourceType
}

func (cfg Config) Initialize(context.Context) (tools.Tool, error) {
	if cfg.Description == "" {
		return nil, fmt.Errorf("description is required for tool %q", cfg.Name)
	}

	projectIdParameter := parameters.NewStringParameter("project_id", "The project_id")
	branchParameter := parameters.NewStringParameter("branch", "The git branch to create")
	refParameter := parameters.NewStringParameter("ref", "The ref to use as the start of a new branch. Defaults to HEAD of current branch if not specified.", parameters.WithStringDefault(""))
	params := parameters.Parameters{projectIdParameter, branchParameter, refParameter}

	annotations := &tools.ToolAnnotations{}
	if cfg.Annotations != nil {
		*annotations = *cfg.Annotations
	}
	readOnlyHint := false
	annotations.ReadOnlyHint = &readOnlyHint

	// finish tool setup
	return Tool{
		BaseTool: tools.NewBaseTool(
			cfg,

View on GitHub (pinned to 8cc6e09de2)

Solutions

1. Add a non-empty description to the tool entry in tools.yaml
2. Check YAML indentation so description parses as a string rather than null

When it happens

Trigger: Thrown at internal/tools/looker/lookercreategitbranch/lookercreategitbranch.go:71 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of googleapis/mcp-toolbox@8cc6e09de2 (2026-09-05). Data as JSON: /api/errors/5bae1f4cc0ccec99. Report an issue: GitHub.