googleapis/mcp-toolbox · error

segment cannot be only whitespace

Error message

segment cannot be only whitespace

What it means

Segment guard in validateSegment: a path segment contains only whitespace characters, which Firestore would reject as a collection ID or document ID.

Source

Thrown at internal/tools/firestore/util/validator.go:113

	return nil
}

// validateSegment validates a single path segment
func validateSegment(segment string, isCollection bool) error {
	segmentType := "document ID"
	if isCollection {
		segmentType = "collection ID"
	}

	// Check for empty segment
	if segment == "" {
		return fmt.Errorf("segment cannot be empty")
	}

	// Check for whitespace-only segment
	if strings.TrimSpace(segment) == "" {
		return fmt.Errorf("segment cannot be only whitespace")
	}

	// Check for single or double period
	if segment == "." || segment == ".." {
		return fmt.Errorf("segment cannot be '.' or '..'")
	}

	// Check for reserved prefix
	if strings.HasPrefix(segment, "__") {
		return fmt.Errorf("%s cannot start with '__' (reserved prefix)", segmentType)
	}

	return nil
}

// IsAbsolutePath checks if a path is an absolute Firestore path
func IsAbsolutePath(path string) bool {
	return absolutePathRegex.MatchString(path)

View on GitHub (pinned to 8cc6e09de2)

Solutions

1. Trim whitespace from segment names
2. Ensure the path does not contain a segment of just spaces or tabs

When it happens

Trigger: Thrown at internal/tools/firestore/util/validator.go:113 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/4c97e26d7f427748. Report an issue: GitHub.