Simple TypeScript MCP Server

Implementation Reference

• src/server.ts:146-190 (handler)

  Handler function for the 'updateNote' MCP tool that validates input, calls the notes store update method, handles note not found and errors, and returns a standardized JSON text response.

  async ({ noteId, title, content }) => {
    try {
      const updatedNote = notesStore.updateNote(noteId, { title, content });
      
      if (!updatedNote) {
        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: updatedNote
            }, null, 2)
          }
        ]
      };
    } catch (err) {
      return {
        content: [
          {
            type: "text",
            text: JSON.stringify({
              success: false,
              error: "Failed to update note",
              noteId
            }, null, 2)
          }
        ]
      };
    }
  },

• src/server.ts:141-145 (schema)

  Zod input schema for the 'updateNote' tool defining required noteId and optional title/content parameters.

  {
    noteId: z.string().describe("The ID of the note to update"),
    title: z.string().optional().describe("The updated title of the note"),
    content: z.string().optional().describe("The updated content of the note")
  },

• src/notes-store.ts:51-67 (helper)

  Core helper method in NotesStore class that performs the actual note update logic by mutating the in-memory note object if it exists.

  updateNote(id: string, updates: { title?: string; content?: string }): Note | undefined {
    const note = this.notes[id];
    
    if (!note) {
      return undefined;
    }
  
    if (updates.title !== undefined) {
      note.title = updates.title;
    }
  
    if (updates.content !== undefined) {
      note.content = updates.content;
    }
    
    return note;
  }

• src/notes-store.ts:2-7 (schema)

  TypeScript interface defining the structure of a Note object, used in the updateNote method and responses.

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

• src/server.ts:139-191 (registration)

  MCP server.tool registration for the 'updateNote' tool, specifying name, input schema, and inline handler function.

  server.tool(
    "updateNote",
    {
      noteId: z.string().describe("The ID of the note to update"),
      title: z.string().optional().describe("The updated title of the note"),
      content: z.string().optional().describe("The updated content of the note")
    },
    async ({ noteId, title, content }) => {
      try {
        const updatedNote = notesStore.updateNote(noteId, { title, content });
        
        if (!updatedNote) {
          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: updatedNote
              }, null, 2)
            }
          ]
        };
      } catch (err) {
        return {
          content: [
            {
              type: "text",
              text: JSON.stringify({
                success: false,
                error: "Failed to update note",
                noteId
              }, null, 2)
            }
          ]
        };
      }
    },
  );