/**
* MCP Tool: comparePrices
*
* Compare prices and market data for multiple cryptocurrency tokens.
* Efficiently batches requests to minimize API calls.
*/
import { coingeckoClient, type TokenPrice } from '../apis/coingecko.js';
import { ValidationError } from '@boosty/mcp-shared';
// ============================================================================
// Input/Output Types
// ============================================================================
export interface ComparePricesInput {
/** Array of token symbols to compare (max 25) */
symbols: string[];
/** Currency for prices (default: 'usd') */
currency?: string;
}
export interface TokenComparison {
symbol: string;
price: number;
change24h: number;
marketCap: number;
volume24h: number;
rank: number;
}
export interface ComparePricesOutput {
currency: string;
tokens: TokenComparison[];
summary: {
count: number;
totalMarketCap: number;
averageChange24h: number;
bestPerformer: TokenComparison | null;
worstPerformer: TokenComparison | null;
highestMarketCap: TokenComparison | null;
lowestMarketCap: TokenComparison | null;
};
timestamp: string;
}
// ============================================================================
// Tool Definition (MCP Schema)
// ============================================================================
export const comparePricesDefinition = {
name: 'comparePrices',
description:
'Compare prices and market data for multiple cryptocurrency tokens in a single request. Returns rankings by market cap and identifies best/worst performers.',
inputSchema: {
type: 'object' as const,
properties: {
symbols: {
type: 'array',
items: { type: 'string' },
description: 'Array of token symbols to compare (e.g., ["BTC", "ETH", "SOL"])',
minItems: 1,
maxItems: 25,
},
currency: {
type: 'string',
description: 'Fiat currency for prices (e.g., usd, eur). Default: usd',
default: 'usd',
},
},
required: ['symbols'],
},
};
// ============================================================================
// Tool Implementation
// ============================================================================
/**
* Validate input parameters
*/
function validateInput(input: unknown): ComparePricesInput {
if (!input || typeof input !== 'object') {
throw new ValidationError('Input must be an object');
}
const { symbols, currency } = input as Record<string, unknown>;
if (!symbols) {
throw new ValidationError('Symbols array is required');
}
if (!Array.isArray(symbols)) {
throw new ValidationError('Symbols must be an array');
}
if (symbols.length === 0) {
throw new ValidationError('Symbols array cannot be empty');
}
if (symbols.length > 25) {
throw new ValidationError('Cannot compare more than 25 tokens at once');
}
// Validate each symbol
const validatedSymbols: string[] = [];
for (let i = 0; i < symbols.length; i++) {
const symbol = symbols[i];
if (typeof symbol !== 'string') {
throw new ValidationError(`Symbol at index ${i} must be a string`);
}
const trimmed = symbol.trim();
if (trimmed.length === 0) {
throw new ValidationError(`Symbol at index ${i} cannot be empty`);
}
if (trimmed.length > 20) {
throw new ValidationError(`Symbol at index ${i} is too long`);
}
validatedSymbols.push(trimmed);
}
// Remove duplicates
const uniqueSymbols = [...new Set(validatedSymbols.map((s) => s.toLowerCase()))];
if (currency !== undefined && typeof currency !== 'string') {
throw new ValidationError('Currency must be a string');
}
return {
symbols: uniqueSymbols,
currency: typeof currency === 'string' ? currency.trim() : 'usd',
};
}
/**
* Compare prices for multiple tokens
*/
export async function comparePrices(input: unknown): Promise<ComparePricesOutput> {
const { symbols, currency = 'usd' } = validateInput(input);
// Batch fetch all prices
const pricesMap = await coingeckoClient.getPrices(symbols, currency);
// Convert to array and add rankings
const tokens: TokenComparison[] = [];
for (const symbol of symbols) {
const priceData = pricesMap.get(symbol.toUpperCase());
if (priceData) {
tokens.push({
symbol: symbol.toUpperCase(),
price: priceData.price,
change24h: Math.round(priceData.change24h * 100) / 100,
marketCap: priceData.marketCap,
volume24h: priceData.volume24h,
rank: 0, // Will be set after sorting
});
}
}
// Sort by market cap and assign ranks
tokens.sort((a, b) => b.marketCap - a.marketCap);
tokens.forEach((token, index) => {
token.rank = index + 1;
});
// Calculate summary statistics
const count = tokens.length;
const totalMarketCap = tokens.reduce((sum, t) => sum + t.marketCap, 0);
const averageChange24h =
count > 0
? Math.round(
(tokens.reduce((sum, t) => sum + t.change24h, 0) / count) * 100
) / 100
: 0;
// Find extremes
let bestPerformer: TokenComparison | null = null;
let worstPerformer: TokenComparison | null = null;
let highestMarketCap: TokenComparison | null = null;
let lowestMarketCap: TokenComparison | null = null;
if (tokens.length > 0) {
bestPerformer = tokens.reduce(
(best, t) => (t.change24h > best.change24h ? t : best),
tokens[0]
);
worstPerformer = tokens.reduce(
(worst, t) => (t.change24h < worst.change24h ? t : worst),
tokens[0]
);
highestMarketCap = tokens[0]; // Already sorted by market cap desc
lowestMarketCap = tokens[tokens.length - 1];
}
return {
currency: currency.toUpperCase(),
tokens,
summary: {
count,
totalMarketCap,
averageChange24h,
bestPerformer,
worstPerformer,
highestMarketCap,
lowestMarketCap,
},
timestamp: new Date().toISOString(),
};
}
