MCP For Claude Marketplace
ICU MessageFormat Validator

ICU MessageFormat Validator MCP Connector for Claude

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A deterministic validator for ICU MessageFormat strings to prevent i18n breakage from unbalanced braces or incorrect syntax.

3 tools Official Updated Oct 1, 2026 Official Vinkius Partner
More Details Connect to 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.

icumessageformatinternationalizationtranslationsyntax-validator

3 tools expose this connector's capabilities to your AI agent.

validate_structural_braces

Validate the structural integrity of braces and quotes in an ICU message

extract_template_variables

}`. Extract template variables from an ICU message

validate_category_logic

Validate the logic within plural/select blocks

See how to talk to your AI agent using ICU MessageFormat Validator.

Check if this ICU string is valid: '{name} has {count, plural, one {# message} other {# messages}}'

The string is structurally sound. The `validate_structural_balances` tool confirms that all braces are paired and the plural categories are correct.

What variables are in this message: 'Hello {user}, you have {items} items.'

The extracted variables are: user, items.

Is this string broken: '{unclosed_brace'

No, the string is invalid. The `validate_structural_braces` tool detected an unmatched opening brace at the start of the string.

The `validate_structural_braces` tool implements a state machine to track escaping. It recognizes that two consecutive single quotes (double-single-quote) represent a literal single quote, preventing the parser from incorrectly terminating an escaped sequence.

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