How to Build an MCP-Powered Contract Query and Delay Service with Node.js

Background

With the growing adoption of MCP, we explore whether, from a business perspective, MCP‑style interactions can allow users to operate the system simply by describing actions in natural language, delivering lower cost, more convenient, and faster experiences.

Implemented Functions

1. Query contract information based on contract status or contract number:

i. question: "Please help me query contracts pending signature"

ii. Invoke MCP matching via MCP client

iii. After user confirmation, call the contract query MCP server

2. Implement business contract extension handling:

i. Describe in natural language the contract I wish to extend

ii. Invoke MCP matching via MCP client – if the contract is not in the previous list, the large model first queries to ensure the contract is valid

iii. After query completion, automatically invoke the delay MCP server

iiii. Return result: extension successful

iiiii. Business system verification – success 🏅

Code Implementation

import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import { z } from "zod";
const QUERY_CONTRACT = "xxxxxxx";
const DELAY_CONTRACT = "xxxxxxx";
// Create server instance
const server = new McpServer({
    name: "contract",
    version: "1.0.0",
    capabilities: {
        resources: {},
        tools: {},
    },
});
// Helper function for making API requests
async function makeRequest(url, params) {
    const headers = {
        "X-Requested-With": 'XMLHttpRequest',
        "content-type": 'application/json',
    };
    try {
        const response = await fetch(url, {
            method: 'POST',
            headers: headers,
            body: JSON.stringify(params),
            credentials: 'include',
        });
        if (!response.ok) {
            throw new Error(`HTTP error! status: ${response.status}`);
        }
        return (await response.json());
    } catch (error) {
        console.error("Error making Contract request:", error);
        return null;
    }
}
// Format alert data
function formatAlert(feature) {
    const props = feature;
    return [
        `合同号: ${props.contractNumber || "Unknown"}`,
        `合同id: ${props.id || "Unknown"}`,
        `版本号: ${props.version || "Unknown"}`,
        `创建人: ${props.creator || "Unknown"}`,
        `合同名称: ${props.name || "Unknown"}`,
        `合同主体: ${props.ouName || "Unknown"}`,
        `合同类型: ${props.typeName || "Unknown"}`,
        `交易方: ${props.refPartiesName || "Unknown"}`,
        `有效日期至: ${props.endTime || "Unknown"}`,
        "---"
    ].join("
");
}
const statusDict = {
    xx: xx
};
// Register tools
server.tool("获取合同列表", "获取某种状态或某个合同的合同列表", {
    state: z.string().describe("两或三字的合同状态 (e.g. xx, xx)"),
    contractNumber: z.string().describe("合同号 (e.g. xxxxxxx,xxxxxxxx,xxxxxxx)"),
}, async ({ state, contractNumber }) => {
    const statusCode = statusDict[state];
    const alertsData = await makeRequest(QUERY_CONTRACT, { status: statusCode, pageIndex: 1, pageSize: 10, searchSource: 0, contractNumber: contractNumber });
    // ...省略业务逻辑
});
server.tool("合同延期", "对指定合同进行延期操作", {
    contractId: z.string().describe("合同id (e.g. 41556890,41556953)"),
    contractNumber: z.string().describe("合同号 (e.g. PE2025A3709738,BEC2025A3709735)"),
    version: z.string().describe("版本号 (e.g. 1,2)"),
    endTime: z.string().describe("有效日期至 (e.g. 2023-08-15 12:00:00)"),
}, async ({ contractId, contractNumber, version, endTime }) => {
    const alertsData = await makeRequest(DELAY_CONTRACT, { endTime: newEndTime, version, contractNumber, contractId });
    // ...省略业务逻辑
});
async function main() {
    const transport = new StdioServerTransport();
    await server.connect(transport);
    console.error("Contract MCP Server running on stdio");
}
main().catch((error) => {
    console.error("Fatal error in main():", error);
    process.exit(1);
});