xc-mcp/dist/utils/error-formatter.js

MCP server that wraps Xcode command-line tools for iOS/macOS development workflows

/**
 * Error formatting utilities for token-efficient error responses
 *
 * Condenses verbose Apple framework errors into concise, actionable messages.
 * Parses nested error dictionaries and extracts only the relevant failure reason.
 */
/**
 * Parse and condense Apple error output
 *
 * Apple errors often include deeply nested dictionaries with redundant information.
 * This extracts the core failure reason and filters out noise.
 *
 * Example input:
 * ```
 * Simulator device failed to terminate com.example.app.
 * Info: ["NSLocalizedFailureReason": found nothing to terminate, ...]
 * ```
 *
 * Example output:
 * ```
 * found nothing to terminate
 * ```
 */
export function condenseAppleError(errorOutput) {
    if (!errorOutput)
        return 'Unknown error';
    // Extract NSLocalizedFailureReason if present (most specific info)
    const reasonMatch = errorOutput.match(/"NSLocalizedFailureReason"\s*:\s*([^,\]]+)/);
    if (reasonMatch) {
        return reasonMatch[1].trim();
    }
    // Extract main error message before nested dict starts
    const mainMessageMatch = errorOutput.match(/^([^[\n]+)/);
    if (mainMessageMatch) {
        const msg = mainMessageMatch[1].trim();
        // Remove trailing period and common prefix
        return msg
            .replace(/\.$/, '')
            .replace(/^Error: /, '')
            .trim();
    }
    // Fallback to first line
    const firstLine = errorOutput.split('\n')[0];
    return firstLine?.trim() || 'Unknown error';
}
/**
 * Format error for LLM response
 *
 * Takes raw stderr and returns a concise error message suitable for MCP tools.
 * Avoids dumping entire error dictionaries while preserving actionable information.
 */
export function formatToolError(stderr, defaultMessage = 'Unknown error') {
    if (!stderr || stderr.trim() === '') {
        return defaultMessage;
    }
    const condensed = condenseAppleError(stderr);
    // Cap message length to prevent token waste
    // Most error messages are actionable in first 140 chars
    const MAX_LENGTH = 140;
    if (condensed.length > MAX_LENGTH) {
        return condensed.substring(0, MAX_LENGTH).trim() + '...';
    }
    return condensed;
}
//# sourceMappingURL=error-formatter.js.map