/**
* MCP JSON file loader for mcpGraph
* Loads mcpServers from a standard MCP configuration JSON file
*/
import { readFileSync } from "node:fs";
import { z } from "zod";
import { logger } from "../logger.js";
import type { ServerConfig } from "../types/config.js";
import { serverConfigSchema } from "./schema.js";
// Schema for MCP JSON file structure
const mcpJsonFileSchema = z.object({
mcpServers: z.record(serverConfigSchema).optional(),
});
/**
* Load mcpServers from an MCP JSON configuration file
* @param filePath - Path to the MCP JSON file (typically mcp.json)
* @returns Record of server name to ServerConfig, or undefined if file doesn't exist or has no mcpServers
* @throws Error if file exists but cannot be parsed or validated
*/
export function loadMcpServers(filePath: string): Record<string, ServerConfig> | undefined {
try {
logger.info(`Loading MCP servers from: ${filePath}`);
const fileContents = readFileSync(filePath, "utf-8");
const parsed = JSON.parse(fileContents) as unknown;
// Validate file structure and server configs (all validated at once)
const validated = mcpJsonFileSchema.parse(parsed);
if (!validated.mcpServers || Object.keys(validated.mcpServers).length === 0) {
logger.info(`No mcpServers found in ${filePath}`);
return undefined;
}
// All servers are already validated by the schema, just cast to the correct type
const servers = validated.mcpServers as Record<string, ServerConfig>;
logger.info(`Loaded ${Object.keys(servers).length} MCP server(s) from ${filePath}`);
return servers;
} catch (error) {
if (error instanceof Error) {
// Check if it's a file not found error
if ((error as NodeJS.ErrnoException).code === "ENOENT") {
throw new Error(`MCP file not found: ${filePath}`);
}
logger.error(`Failed to load MCP file: ${error.message}`);
throw error;
}
throw new Error("Unknown error loading MCP file");
}
}
