/**
* Copyright (c) 2025 HUDU MCP Server Contributors
* SPDX-License-Identifier: MIT
*/
/**
* Maximum response size in characters (approximately 1MB in tokens)
* Using conservative estimate: 1 token ≈ 4 characters
* 1MB = 1,048,576 tokens ≈ 4,194,304 characters
* Using 3MB as safety margin
*/
const MAX_RESPONSE_SIZE = 3_000_000;
/**
* Truncate response data if it exceeds the maximum size
*/
export function truncateResponse(data: any): { data: any; truncated: boolean; originalSize: number } {
const jsonString = JSON.stringify(data, null, 2);
const originalSize = jsonString.length;
if (originalSize <= MAX_RESPONSE_SIZE) {
return {
data,
truncated: false,
originalSize
};
}
// If response is too large, truncate arrays and objects
const truncatedData = truncateDataRecursively(data, MAX_RESPONSE_SIZE * 0.8); // Use 80% of limit for safety
return {
data: {
...truncatedData,
_truncation_info: {
truncated: true,
original_size_chars: originalSize,
truncated_size_chars: JSON.stringify(truncatedData, null, 2).length,
message: 'Response was truncated due to size limits. Use pagination parameters to get smaller chunks of data.'
}
},
truncated: true,
originalSize
};
}
/**
* Recursively truncate data structures
*/
function truncateDataRecursively(data: any, maxSize: number): any {
if (typeof data !== 'object' || data === null) {
return data;
}
if (Array.isArray(data)) {
const truncatedArray = [];
let currentSize = 0;
for (let i = 0; i < data.length; i++) {
const item = data[i];
const itemString = JSON.stringify(item, null, 2);
if (currentSize + itemString.length > maxSize) {
// Add truncation info
truncatedArray.push({
_truncated: true,
_message: `Array truncated at index ${i}. Original length: ${data.length}, showing first ${i} items.`,
_remaining_items: data.length - i
});
break;
}
truncatedArray.push(truncateDataRecursively(item, maxSize / 10)); // Limit individual items
currentSize += itemString.length;
}
return truncatedArray;
}
// Handle objects
const truncatedObject: any = {};
let currentSize = 0;
const entries = Object.entries(data);
for (const [key, value] of entries) {
const valueString = JSON.stringify(value, null, 2);
if (currentSize + valueString.length > maxSize) {
truncatedObject._truncated = true;
truncatedObject._message = `Object truncated. Some properties were omitted due to size limits.`;
break;
}
// Special handling for large text fields
if (typeof value === 'string' && value.length > 10000) {
truncatedObject[key] = value.substring(0, 10000) + '... [truncated]';
} else {
truncatedObject[key] = truncateDataRecursively(value, maxSize / 10);
}
currentSize += valueString.length;
}
return truncatedObject;
}
/**
* Create a standardized MCP response with truncation support
*/
export function createMcpResponse(data: any, summary?: string): any {
const { data: responseData, truncated, originalSize } = truncateResponse(data);
const response = {
content: [
{
type: 'text',
text: JSON.stringify(responseData, null, 2)
}
]
};
// Add truncation warning to summary if needed
if (truncated && summary) {
const truncationWarning = ` [Response truncated from ${Math.round(originalSize / 1000)}KB due to size limits]`;
responseData.summary = summary + truncationWarning;
}
return response;
}
