User Management MCP Server

Instructions

Implementation Reference

• src/server.ts:133-177 (handler)

  Handler function that generates random user data using LLM sampling, parses the JSON response, and creates the user via the createUser helper function.

  async () => {
    const res = await server.server.request(
      {
        method: "sampling/createMessage",
        params: {
          messages: [
            {
              role: "user",
              content: {
                type: "text",
                text: "Generate fake user data. The user should have a realistic name, email, address, age, and phone number. Return this data as a JSON object with no other text or formatter so it can be used with JSON.parse.",
              },
            },
          ],
          maxTokens: 1024,
        },
      },
      CreateMessageResultSchema
    )
  
    if (res.content.type !== "text") {
      return {
        content: [{ type: "text", text: "Failed to generate user data" }],
      }
    }
  
    try {
      const fakeUser = JSON.parse(
        res.content.text
          .trim()
          .replace(/^```json/, "")
          .replace(/```$/, "")
          .trim()
      )
  
      const id = await createUser(fakeUser)
      return {
        content: [{ type: "text", text: `User ${id} created successfully` }],
      }
    } catch {
      return {
        content: [{ type: "text", text: "Failed to generate user data" }],
      }
    }
  }

• src/server.ts:123-178 (registration)

  Registration of the create-random-user tool on the MCP server, specifying description, metadata, and inline handler.

  server.tool(
    "create-random-user",
    "Create a random user with fake data",
    {
      title: "Create Random User",
      readOnlyHint: false,
      destructiveHint: false,
      idempotentHint: false,
      openWorldHint: true,
    },
    async () => {
      const res = await server.server.request(
        {
          method: "sampling/createMessage",
          params: {
            messages: [
              {
                role: "user",
                content: {
                  type: "text",
                  text: "Generate fake user data. The user should have a realistic name, email, address, age, and phone number. Return this data as a JSON object with no other text or formatter so it can be used with JSON.parse.",
                },
              },
            ],
            maxTokens: 1024,
          },
        },
        CreateMessageResultSchema
      )
  
      if (res.content.type !== "text") {
        return {
          content: [{ type: "text", text: "Failed to generate user data" }],
        }
      }
  
      try {
        const fakeUser = JSON.parse(
          res.content.text
            .trim()
            .replace(/^```json/, "")
            .replace(/```$/, "")
            .trim()
        )
  
        const id = await createUser(fakeUser)
        return {
          content: [{ type: "text", text: `User ${id} created successfully` }],
        }
      } catch {
        return {
          content: [{ type: "text", text: "Failed to generate user data" }],
        }
      }
    }
  )

• src/server.ts:201-207 (helper)

  Helper function used by create-random-user (and create-user) to persist new user data to users.json file.

  async function createUser(params: { name: string; email: string; address: string; age: number; phone: string }) {
      const users = await import("./data/users.json", { with: { type: "json" } }).then((m) => m.default);
      const newId = users.length + 1;
      const newUsers = [...users, { id: newId, ...params }];
      writeFileSync("./src/data/users.json", JSON.stringify(newUsers, null, 2));
      return newId;
  }