Langfuse MCP Server

import { z } from 'zod'; import { LangfuseAnalyticsClient } from '../langfuse-client.js'; import { TracesResponse } from '../types.js'; export const getTracesSchema = z.object({ from: z.string().datetime().optional(), to: z.string().datetime().optional(), limit: z.number().min(1).max(100).default(25), page: z.number().min(1).default(1), orderBy: z.enum(['timestamp', 'totalCost', 'name']).default('timestamp'), orderDirection: z.enum(['asc', 'desc']).default('desc'), userId: z.string().optional(), name: z.string().optional(), tags: z.array(z.string()).optional(), environment: z.string().optional(), minCost: z.number().optional(), maxCost: z.number().optional(), }); export async function getTraces( client: LangfuseAnalyticsClient, args: z.infer<typeof getTracesSchema> ) { // Build tags array with environment and other filters const tags: string[] = []; if (args.environment) { tags.push(`environment:${args.environment}`); } if (args.tags) { tags.push(...args.tags); } try { const response = await client.listTraces({ page: args.page, limit: args.limit, name: args.name, userId: args.userId, tags: tags.length > 0 ? tags : undefined, orderBy: args.orderBy, orderDirection: args.orderDirection, fromTimestamp: args.from, toTimestamp: args.to, }); let traces = []; if (response.data && Array.isArray(response.data)) { traces = response.data.map((trace: any) => ({ id: trace.id, name: trace.name || 'Unnamed trace', timestamp: trace.timestamp || trace.startTime, totalCost: trace.totalCost || 0, totalTokens: trace.totalTokens || 0, userId: trace.userId, tags: trace.tags || [], metadata: trace.metadata, sessionId: trace.sessionId, version: trace.version, release: trace.release, })); // Apply cost filters if specified if (args.minCost !== undefined) { traces = traces.filter((trace: any) => trace.totalCost >= args.minCost!); } if (args.maxCost !== undefined) { traces = traces.filter((trace: any) => trace.totalCost <= args.maxCost!); } // Apply ordering (API might handle this, but ensure local sorting) traces.sort((a: any, b: any) => { let comparison = 0; switch (args.orderBy) { case 'timestamp': comparison = new Date(a.timestamp).getTime() - new Date(b.timestamp).getTime(); break; case 'totalCost': comparison = (a.totalCost || 0) - (b.totalCost || 0); break; case 'name': comparison = (a.name || '').localeCompare(b.name || ''); break; } return args.orderDirection === 'desc' ? -comparison : comparison; }); } const result: TracesResponse = { projectId: client.getProjectId(), traces, pagination: { page: args.page, limit: args.limit, total: response.meta?.totalItems || traces.length, }, }; return { content: [ { type: 'text' as const, text: JSON.stringify(result, null, 2), }, ], }; } catch (error) { // Return error information for debugging const errorMessage = error instanceof Error ? error.message : 'Unknown error'; return { content: [ { type: 'text' as const, text: JSON.stringify({ error: 'Failed to fetch traces', message: errorMessage, requestParams: { from: args.from, to: args.to, name: args.name, limit: args.limit, orderBy: args.orderBy, }, }, null, 2), }, ], isError: true, }; } }