Simple TypeScript MCP Server

Implementation Reference

• src/server.ts:18-62 (handler)

  The main handler function for the MCP 'getNote' tool. It takes noteId, fetches the note from notesStore, handles not found and errors, and returns MCP-formatted content with JSON stringified response.

  async ({ noteId }) => {
    try {
      const note = notesStore.getNote(noteId);
      
      if (!note) {
        return {
          content: [
            {
              type: "text",
              text: JSON.stringify({
                success: false,
                error: "Note not found",
                noteId
              }, null, 2)
            }
          ]
        };
      }
  
      return {
        content: [
          {
            type: "text",
            text: JSON.stringify({
              success: true,
              note
            }, null, 2)
          }
        ]
      };
    } catch (err) {
      return {
        content: [
          {
            type: "text",
            text: JSON.stringify({
              success: false,
              error: "Failed to retrieve note",
              noteId
            }, null, 2)
          }
        ]
      };
    }
  },

• src/server.ts:15-17 (schema)

  Input schema validation for the getNote tool using Zod, defining the required 'noteId' parameter.

  {
    noteId: z.string().describe("The ID of the note to retrieve")
  },

• src/server.ts:14-14 (registration)

  The tool name 'getNote' registration within the server.tool() call.

  "getNote",

• src/notes-store.ts:30-32 (helper)

  Helper method in NotesStore class that retrieves a single note by ID from the in-memory store.

  getNote(id: string): Note | undefined {
    return this.notes[id];
  }

• src/notes-store.ts:2-7 (schema)

  TypeScript interface defining the structure of a Note object returned by getNote.

  export interface Note {
    id: string;
    title: string;
    content: string;
    createdAt: string;
  }