googleapis/mcp-toolbox · error

parameter type %q cannot specify 'embeddedBy'

Error message

parameter type %q cannot specify 'embeddedBy'

What it means

ParseParameter rejects array/map-typed parameters (and others that aggregate values) that declare an 'embeddedBy' field, because embedding is only meaningful for scalar parameter types whose value is spliced into a string template. The error fires during config parsing of a parameter block in tools.yaml.

Source

Thrown at internal/util/parameters/parameters.go:432

func ParseParameter(ctx context.Context, p map[string]any, paramType string) (Parameter, error) {
	dec, err := util.NewStrictDecoder(p)
	if err != nil {
		return nil, fmt.Errorf("error creating decoder: %w", err)
	}
	switch paramType {
	case TypeString:
		a := &StringParameter{}
		if err := dec.DecodeContext(ctx, a); err != nil {
			return nil, fmt.Errorf("unable to parse as %q: %w", paramType, err)
		}
		return a, nil
	case TypeInt:
		a := &IntParameter{}
		if err := dec.DecodeContext(ctx, a); err != nil {
			return nil, fmt.Errorf("unable to parse as %q: %w", paramType, err)
		}
		if a.GetEmbeddedBy() != "" {
			return nil, fmt.Errorf("parameter type %q cannot specify 'embeddedBy'", paramType)
		}
		return a, nil
	case TypeFloat:
		a := &FloatParameter{}
		if err := dec.DecodeContext(ctx, a); err != nil {
			return nil, fmt.Errorf("unable to parse as %q: %w", paramType, err)
		}
		if a.GetEmbeddedBy() != "" {
			return nil, fmt.Errorf("parameter type %q cannot specify 'embeddedBy'", paramType)
		}
		return a, nil
	case TypeBool:
		a := &BooleanParameter{}
		if err := dec.DecodeContext(ctx, a); err != nil {
			return nil, fmt.Errorf("unable to parse as %q: %w", paramType, err)
		}
		if a.GetEmbeddedBy() != "" {
			return nil, fmt.Errorf("parameter type %q cannot specify 'embeddedBy'", paramType)

View on GitHub (pinned to 8cc6e09de2)

Solutions

1. Remove 'embeddedBy' from the array/map parameter
2. Switch the parameter to a scalar type if embedding behavior is needed

When it happens

Trigger: Thrown at internal/util/parameters/parameters.go:432 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/0038ee30365fd853. Report an issue: GitHub.