googleapis/mcp-toolbox · error

description is required for tool %q

Error message

description is required for tool %q

What it means

Config.Initialize for firestore-querycollection requires a non-empty description, rejecting the config at load time when cfg.Description is empty. Descriptions are part of the tool's MCP manifest exposed to clients.

Source

Thrown at internal/tools/firestore/firestorequerycollection/firestorequerycollection.go:116

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{}

// ToolConfigType returns the type of tool configuration
func (cfg Config) ToolConfigType() string {
	return resourceType
}

// Initialize creates a new Tool instance from the configuration
func (cfg Config) Initialize(context.Context) (tools.Tool, error) {
	if cfg.Description == "" {
		return nil, fmt.Errorf("description is required for tool %q", cfg.Name)
	}

	// Create parameters
	params := createParameters()

	return Tool{
		BaseTool: tools.NewBaseTool(
			cfg,
			tools.GetAnnotationsOrDefault(cfg.Annotations, tools.NewReadOnlyAnnotations),
			tools.Manifest{Description: cfg.Description, Parameters: params.Manifest(), AuthRequired: cfg.AuthRequired},
			params,
		),
	}, nil
}

func (t Tool) GetSourceName() string {
	return t.Cfg.Source
}

View on GitHub (pinned to 8cc6e09de2)

Solutions

1. Add a non-empty `description:` field to the firestore-querycollection tool config.
2. Verify env-var/templated description values are populated at render time.

Example fix

// before
  query_collection:
    kind: firestore-querycollection
    source: my-fs
// after
  query_collection:
    kind: firestore-querycollection
    source: my-fs
    description: Query documents from a Firestore collection

if strings.TrimSpace(cfg.Description) == "" {
	return errors.New("firestore-querycollection tool requires a non-empty description")
}

tool, err := cfg.Initialize(ctx)
if err != nil {
	return fmt.Errorf("tool init failed: %w", err)
}

When it happens

Trigger: A firestore-querycollection tool config missing its `description:` field or defining it as an empty string.

Common situations: Omitting the field in hand-written YAML; templated configs with unfilled description placeholders.

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/5d031f347987aefc. Report an issue: GitHub.