ICU MessageFormat Validator MCP Connector for Claude

The ICU MessageFormat Validator is a specialized utility designed to ensure the structural integrity of internationalization strings. By implementing a deterministic finite automaton (DFA), the server performs deep analysis of message content to identify critical errors that break translation logic. The validate_structural_braces tool tracks brace depth and single-quote escaping states, specifically detecting unmatched '{' or '}' characters and unescaped quotes that would otherwise corrupt the interpolation engine. Additionally, the validate_category_logic tool verifies that all identifiers within plural and select blocks belong to the approved set of categories like zero, one, two, few, many, and other, ensuring the 'other' category is always present. For developers needing to identify dynamic content, the extract_template_variables tool parses strings to reveal all unique variable names used in the template, providing a clear inventory of required interpolation parameters.