googleapis/mcp-toolbox · error

description is required for tool %q

Error message

description is required for tool %q

What it means

Initialize for looker-update-dashboard-layout-component enforces a non-empty `description` on the tool config before constructing its parameters. The description is required for MCP tool registration, so an empty one aborts initialization with this error.

Source

Thrown at internal/tools/looker/lookerupdatedashboardlayoutcomponent/lookerupdatedashboardlayoutcomponent.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)
	}

	componentIdParam := parameters.NewStringParameter("dashboard_layout_component_id", "The ID of the dashboard layout component to update.")
	layoutIdParam := parameters.NewStringParameter("dashboard_layout_id", "The ID of the target dashboard layout (tab) to move the component to.", parameters.WithStringRequired(false))
	rowParam := parameters.NewIntParameter("row", "The new row position.", parameters.WithIntRequired(false))
	columnParam := parameters.NewIntParameter("column", "The new column position.", parameters.WithIntRequired(false))
	widthParam := parameters.NewIntParameter("width", "The new width.", parameters.WithIntRequired(false))
	heightParam := parameters.NewIntParameter("height", "The new height.", parameters.WithIntRequired(false))

	params := parameters.Parameters{
		componentIdParam,
		layoutIdParam,
		rowParam,
		columnParam,
		widthParam,
		heightParam,
	}

View on GitHub (pinned to 8cc6e09de2)

Solutions

1. Add a non-empty `description:` to the tool entry
2. Fix the config generator/template to always emit description
3. Add a startup-time validation that all tool configs have descriptions

Example fix

// before
tools:
  update_layout_component:
    kind: looker-update-dashboard-layout-component
    source: my-looker-source
// after
tools:
  update_layout_component:
    kind: looker-update-dashboard-layout-component
    source: my-looker-source
    description: Update or move a dashboard layout component within a Looker dashboard.

if cfg.Description == "" {
    return errors.New("looker-update-dashboard-layout-component tool requires a non-empty description")
}

tool, err := cfg.Initialize(ctx)
if err != nil {
    if strings.Contains(err.Error(), "description is required") {
        return fmt.Errorf("set `description` for tool %q", cfg.Name)
    }
    return err
}

When it happens

Trigger: A kind looker-update-dashboard-layout-component tool entry is parsed with no `description:` field or an empty string, during server startup or dynamic config load.

Common situations: Hand-written configs missing the description; templating that omits empty values; bulk config migrations that dropped the field.

Related errors

• description is required for tool %q
• description is required for tool %q
• description is required for tool %q
• description is required for tool %q
• description is required for tool %q

AI-assisted analysis of googleapis/mcp-toolbox@8cc6e09de2 (2026-09-05). Data as JSON: /api/errors/a008f8d600645a6a. Report an issue: GitHub.