Hey there!

In this tutorial, we're going to build an app that ChatGPT can actually control.

The idea is simple: instead of ChatGPT just answering questions, it can now create notes, manage your tasks, search your data, or do pretty much anything you want, all through natural conversation.

Basically, we'll build a system where you can:

• Tell ChatGPT "Create a note about my meeting with John" and it actually does it

• Ask "Show me all my notes from last week" and see real results

• Say "Search for notes about project ideas" and get instant answers

• Build any personal app (todo lists, journals, recipe keepers) that ChatGPT can manage

By the end of this guide, you'll have your own app running, connected to ChatGPT, and ready to use through simple conversation. 

Let's get started! 

What You're Building

So here's the thing: ChatGPT is powerful, but normally it can't actually do anything with your personal data. It can't save your notes, manage your tasks, or interact with apps you build.

This setup changes that completely.

Think of it in three simple parts:

ChatGPT = where you talk naturally, like "add this to my todo list"

The Bridge (MCP) = the translator that understands what ChatGPT wants to do

Your App = where the real work happens, storing data and executing actions

Here's how they connect: 

Real Example: Notes App

Let's use a Notes App as our example throughout this tutorial because it's simple, useful, and demonstrates all the core concepts.

This same pattern works for any app you can imagine: todo lists, expense trackers, habit journals, recipe collections, you name it.

What You'll Need

Before we start building, let's make sure you have everything ready. Don't worry, almost everything has a free tier.

 An Emergent Account - This is where you’ll build your app without writing code. Emergent gives you your database, hosting, backend logic, and a full environment to run everything. (Cost: Free tier available) → Sign up at emergent.sh

A ChatGPT Account - This is the AI interface you’ll use to interact with your app. Works with Plus, Pro, Go (Business/Enterprise plans don’t support this yet). → Sign up at chatgpt.com

One Account for Public Access - You’ll need to expose your app to the internet so ChatGPT can reach it. You can choose either:

• Cloudflare Tunnel (Recommended for beginners): No signup required, easiest setup, gives you a temporary URL that changes each session, and it’s completely free.
  
  
  

• ngrok (Recommended for ongoing use): Requires signup but provides a stable URL with a static domain - great for apps you’ll use regularly. (Free tier available)

Phase 1: Build Your App

Now that you have everything ready, let's build the actual app.

For this tutorial, we're building the Notes App. Here's what it needs to do:

That's it. Simple, functional, and useful.

Step 2: Tell Emergent What to Build

Here's where things get interesting.

Instead of coding, you just describe what you want in plain English.

Open Emergent and enter this prompt:

Build me a notes app where:

- Anyone can create notes with a title and content

- Users can see all their notes in a nice grid layout

- Users can search through notes by keywords

- Users can delete notes they don't want anymore

- No login system needed for now (we'll add that later if needed)

- Make it look modern and clean with soft shadows and good spacing

- Use a white background with subtle colors

Hit enter, and Emergent's agent gets to work. 

In a few minutes, you should have the first version of the app created. For me it was this : 

Step 4: Test Your App

Before moving on, make sure everything works:

1. Click the preview link Emergent gives you

2. Create a few test notes (try titles like "Shopping List" and "Project Ideas")

3. Search for one of them using the search box

4. Delete a note to make sure that works

✅ Checkpoint: If you can create, view, search, and delete notes, you're ready to move on. 

I also wanted some UI changes - like different colors for different categories of notes, which the first version was not giving : 

So, I simply asked the agent - “Can you give different colors for different categories of notes?” 

The agent takes your feedback and proceeds to make changes to /app/frontend/src/App.js and gives you exactly what you want : 

Phase 2: Add the Bridge (MCP)

Now comes the important part: connecting your app to ChatGPT. 

Without MCP, ChatGPT has no way to interact with your notes app. It can talk about notes, but it can't actually create, read, or delete them.

With MCP, you define "tools" that ChatGPT can use. These are like buttons ChatGPT can press:

For the Notes App:

• create_note -adds a new note

• list_notes -shows all notes

• search_notes -finds notes by keyword

• delete_note - removes a note

When you tell ChatGPT "Create a note about my meeting," it knows to use the create_note tool and passes the right information to your app.

Ask Emergent to Add MCP

Go back to your Emergent chat and enter this prompt:

Add MCP (Model Context Protocol) support to this app so I can use it from ChatGPT.

Make it work with ChatGPT by:

1. Creating an MCP server using Streamable HTTP transport

2. Adding these tools:

   - create_note (takes title and content)

   - list_notes (returns all notes)

   - search_notes (takes a query string)

   - delete_note (takes note ID)

3. Set it up to run on port 8002

4. Give me step-by-step instructions for connecting it to ChatGPT

What Emergent Creates

Emergent generates a new file called mcp_server_http.py in your backend folder.

This script:

• Runs alongside your main app (on port 8002)

• Listens for requests from ChatGPT

• Translates those requests into actual app functions

• Sends results back to ChatGPT

You don't need to understand how it works, just that it exists and connects the pieces.

Phase 3: Make It Accessible Online

Right now, your app and MCP server are running on Emergent's platform, but they're not publicly accessible.

ChatGPT needs to reach your MCP server over the internet, so we need to expose it.

For your first build, I recommend Cloudflare Tunnel because it's faster to set up.

Once you're building apps you want to use long-term, switch to ngrok.

Tell the Emergent agent: 

“Expose my MCP server using Cloudflare Tunnel”

Emergent will:

1. Install Cloudflare's tunnel software

2. Start the tunnel pointing to your MCP server (port 8002)

3. Give you a public URL like https://abc-def-123.trycloudflare.com

Your final URL must end with /mcp.

Ask the agent “Can you give me the connector url I can use to connect it to chatgpt?

The agent will give you an URL that looks like this : 

• https://abc-def-123.trycloudflare.com/mcp

• https://my-notes-app.ngrok-free.app/mcp

ChatGPT specifically looks for the /mcp endpoint to connect to your bridge.

Phase 4: Connect to ChatGPT

Now comes the exciting part: telling ChatGPT about your app so you can start using it through conversation.

Step 1: Enable Developer Mode in ChatGPT 

1. First, go to Settings and open your Personal Settings.

2. Then, navigate to Apps and Connectors.

3. Scroll down to the Advanced Settings section and turn on Developer Mode. 

Step 2: Create Your Connector

Still in the Apps & Connectors section:

1. Click the Create button (usually says "Create new connector")

2. You'll see a form with three fields. Fill them in: 

Once it is connected, you will see it in the Apps and Connectors tab : 

To summarize what we have done so far - 

You’ve just built an app on Emergent, which serves as both your notes database and interface. 

Then, you added an MCP bridge that connects ChatGPT with your app, exposed that bridge to the internet using a public URL, and told ChatGPT where to find it. 

Now, ChatGPT knows new actions it can take and exactly how to execute them through your app. 

Testing & Using Your App

This is where everything comes together. Let's actually use your app through ChatGPT.

How to Activate Your App

1. Start a new chat in ChatGPT (important: it must be a fresh conversation)

2. Click the "+" button above the input box

3. Select More → Notes App (or whatever you named your connector)

4. You'll see the app name appear above the input box, confirming it's active

Now you can talk to ChatGPT naturally, and it will interact with your notes app. 

Example Conversation

Create Note :

Type in Chatgpt : “Create a note called Shopping List with: Milk, Eggs, Bread. Category: General” 

Once you refresh your note taking app, an automatic list should appear : 

You can use this tool across different conversations too -  remember, it supports multiple actions: 

• create_note (add a new note with title, content, and category), 

• delete_note (remove a note by its ID), 

• get_note (retrieve a specific note), 

• list_notes (view all notes or filter by category), and 

• search_notes (find notes by keyword in title or content). 

So go ahead, experiment and have fun with it!

Understanding the Conversation Flow

Here's what happens behind the scenes when you say "Create a note about the meeting":

1. ChatGPT understands your intent - it recognizes you want to create a note

2. ChatGPT calls the create_note tool - it passes the title="Meeting" and content="..."

3. MCP bridge receives the request - it translates this into your app's format

4. Your app saves the note - the database stores the new entry

5. Response travels back - MCP → ChatGPT → you see confirmation

All of this happens in under a second, making it feel like ChatGPT is directly controlling your app. 

Debugging :  

Sometimes, the process might not go as smoothly. 

Some common situations like these can arise : 

Either way, you can just tell the Emergent agent to take care of something if it's not working and it will autonomously debug itself. 

You can also attach screenshots of the error and the agent will return a working version! 

Can Other People Use My App?

Yes! There are a few ways to share:

Option 1: Share the connector Give someone your connector name, and they can add it to their ChatGPT if your tunnel is public.

Option 2: Deploy with authentication Add user accounts to your app so multiple people can have their own data.

Option 3: Make it a public tool Deploy your app properly (not just a tunnel) and share it with the community.

For personal use, Option 1 works great. For serious projects, go with Option 2 or 3. 

You can also use the one we just created! 

Preview Link of the app built on Emergent : https://notegrid.preview.emergentagent.com/ 

Connector URL : https://best-carolina-literally-republican.trycloudflare.com/mcp 

What You Can Build Next

Once you've got the basics down, here are some ideas to take your apps further:

1. Add User Authentication

Right now, anyone with your app link can access all the notes. Add user accounts so:

• Each person has their own private data

• You can share the app with friends or family

• Data stays secure and separated

Tell Emergent: 

“Add user authentication with email and password. Each user should only see their own notes.”

2. Build Mobile-Friendly Views

Make your app work great on phones by asking Emergent: 

“Make this app fully responsive for mobile devices with touch-friendly buttons.”

3. Add Rich Features

Enhance your notes app with:

• Tags and categories -organize notes by topic

• Favorites -star important notes

• Timestamps -see when notes were created/edited

• Markdown support -format notes with headers, lists, bold text

• Attachments -upload images or files to notes

4. Create Related Apps

Use the same skills to build:

• Expense tracker with category analysis and budget alerts

• Reading list with ratings and progress tracking

• Contact manager with notes about each person

• Travel planner with itineraries and packing lists

Wrapping Up

You just built something powerful: an app that responds to natural conversation through ChatGPT.

Instead of clicking through menus and filling out forms, you can now:

• Create data by talking naturally

• Search and find information by asking questions

• Manage your personal information through simple conversation

• Build tools that actually fit how you think and work

Thousands of Emergent users are building apps like this to manage their lives, track their goals, and organize their world without learning to code.

Some are building personal CRMs to track relationships, others are creating custom productivity tools, and many are making apps for problems that off-the-shelf software doesn't solve.

Your turn: What will you build next?

The pattern you learned here works for literally any app where you want ChatGPT to take actions. The only limit is your imagination.

Ready to start?

Head to emergent.sh and tell the agent what you want to build!