ChatGPT with Microsoft To Do
Learn how to build a custom GPT in ChatGPT that manages tasks in Microsoft To Do using Caddey — no coding required.
May 24, 2025
In this tutorial, you'll learn how to integrate Microsoft To Do with ChatGPT using Caddey. By setting up a custom GPT that connects to Caddey, you'll be able to list your tasks and add new tasks to Microsoft To Do directly from a ChatGPT conversation – all without writing any code. Let's get started!
Prerequisites
Make sure you have the following ready before you begin:
- ChatGPT Plus/Pro subscription: Access to custom GPT creation features in ChatGPT.
- Caddey account: A Caddey account to create an agent and connect Microsoft To Do.
- Microsoft account with To Do access: A personal or work Microsoft account that you use with Microsoft To Do (the tasks app). You’ll use this to authorize Caddey to manage your tasks.
Step 1: Create a Caddey Agent
First, set up an agent in Caddey to act as the bridge between ChatGPT and Microsoft To Do:
- Log in to Caddey: Sign in to your Caddey account and go to the Agents section of the dashboard.
- Add a new agent: Click Add Agent and enter a name (for example, "To Do Agent") and an optional description for your agent.
- Save the agent: After filling in the details, save your new agent. Caddey will create the agent and immediately display its API Key.
- Copy the API key: Copy the agent’s API key now and keep it somewhere safe. This key will not be shown again, and you'll need it later to connect ChatGPT to Caddey.
The Caddey agent represents your assistant’s identity in Caddey. Its API key will allow ChatGPT to securely access the tools (like Microsoft To Do actions) that you connect to this agent.
Step 2: Connect Microsoft To Do in Caddey
Next, connect your Microsoft To Do account to Caddey as an app:
- Go to Caddey Apps: In the Caddey dashboard, navigate to the Apps section and open the Marketplace.
- Find Microsoft To Do: Browse or search the marketplace for Microsoft To Do. Once you find it, click the Connect button on the Microsoft To Do app.
- Configure key: A prompt will appear to choose a key. Choose the published OAuth key.
- Complete the connection: After connecting, the Microsoft To Do app will be added to your Caddey account. You should see Microsoft To Do listed under your connected apps.
Step 3: Create a Toolbox for Microsoft To Do
Caddey uses toolboxes to group related tools (actions) from your apps. This step shows how to create a toolbox to organize Microsoft To Do tools.
- Navigate to Toolboxes: In your Caddey dashboard, go to the Toolboxes section.
- Create a new toolbox: Click Create Toolbox. Give your toolbox a name, for example, "Microsoft To Do Tools", and add a description (like "Tools to manage my tasks"). Save the new toolbox.
- Add To Do tools: With your toolbox created, click Add Tools to add tools to it. From the list of available tools, select the ones related to Microsoft To Do – for example, List Tasks (to retrieve tasks) and Create Task (to add a new task). You can choose any other Microsoft To Do actions you see and want to use.
Step 4: Assign the Toolbox to Your Agent
Now link the Microsoft To Do tools to the Caddey agent you created:
- Open your agent settings: Go back to the Agents section and select the agent you created in Step 1 (e.g., "To Do Agent").
- Add a toolbox to the agent: In the agent’s toolboxes tab, find the option to Add Toolbox. Click this and choose the Microsoft To Do Tools toolbox you created in Step 3 from the list.
Step 5: Create a Custom GPT in ChatGPT
With Caddey set up, the next part is in ChatGPT. We'll create a custom GPT (a personalized ChatGPT instance) that can use the Caddey agent's tools:
- Open ChatGPT settings: Log in to your ChatGPT Plus/Pro account. In the ChatGPT interface, find and click on Explore GPTs (or a section for custom GPTs/GPT builder).
- Start a new GPT: Click the Create (or New GPT) button to begin making a custom GPT.
- Enter a title: Give your custom GPT a name. For example, "To Do Assistant". This will be the name of the assistant (you'll see it in your GPT list).
- Add a description: Provide a short description, such as "Helps manage my Microsoft To Do tasks via Caddey" – this is just for your reference or if you share the GPT with others.
- (Optional) Add instructions or personality: You can add some instructions or a prompt to guide how this assistant behaves. For instance, you might note that it can manage tasks and should use the Caddey tools when appropriate. (This step is optional, but you could include a friendly greeting or usage tips for the assistant here.)
After filling in the basic details, you’re ready to connect the GPT to Caddey’s API.
Step 6: Connect the GPT to Caddey
Now we'll link your custom GPT to the Caddey agent’s tools using an API action:
- Add a new action: In the GPT builder interface, find the option to Add Action (this lets your GPT call external APIs).
- Configure authentication: Still in the action settings, you'll need to add your Caddey agent’s API key for authentication:
- Select API Key as the authentication method.
- Choose the Custom Header option (since Caddey expects the API key in a header).
- For the header name, enter
X-API-KEY
. - In the API key value field, paste the Caddey agent API key that you copied in Step 1.
The API key you entered allows ChatGPT to use your Caddey agent. If you ever need to revoke access, you can delete or regenerate the agent’s API key in Caddey.
-
Import Caddey’s OpenAPI schema: Next, load the definition of Caddey’s tools API so ChatGPT knows what actions are available:
- Choose the option to Import OpenAPI schema (from a URL).
- Enter the URL:
https://api.caddey.ai/v3/api-docs/tools
and import it.
-
Confirm the tools endpoints: After importing, you should see that ChatGPT has loaded the Caddey tools endpoints. In particular, look for:
- GET
/tools/query
– used to search or list the available tools your agent can access. - POST
/tools/{toolId}/execute
– used to execute a specific tool (like listing tasks or creating a task).
These are the actions ChatGPT will use to interact with your Microsoft To Do tools via Caddey.
- GET
-
Save the action: Once everything is configured, save or confirm this new action in the GPT builder. Your custom GPT is now configured to communicate with Caddey.
Step 7: Test the Integration in ChatGPT
It’s time to try out your new GPT and make sure everything works as expected. Use the preview mode in the GPT builder or save and start a conversation with your custom GPT:
Note: The first time you execute any Microsoft To Do action, ChatGPT will prompt you to authenticate your Microsoft account by providing a link. Click the link, sign in, and grant permission before continuing.
- Ask for available tools: Start by asking your assistant something like “What tools do you have?” or “What can you do?” The GPT will call Caddey’s
/tools/query
endpoint to retrieve the list of tools. It should respond with the tools you added, for example, a list that includes List Tasks and Create Task (and any other tools in the toolbox). - List your tasks: Now, ask the assistant to retrieve your tasks. You can say something like “List my tasks” or “What’s on my to-do list?” The GPT will use the List Tasks tool via Caddey to fetch your current Microsoft To Do tasks and display them in the chat. (If you have tasks in To Do, you should see them listed; if not, the assistant might say you have no tasks or an empty list.)
- Create a new task: Finally, test adding a task. For example, type: “Add a task to buy groceries tomorrow.” The assistant will use the Create Task tool and attempt to create a new task in your Microsoft To Do with the title "buy groceries" and a due date for tomorrow. It should then respond confirming that the task was created.
- Verify the action: (Optional) You can open your Microsoft To Do app or website and check that the new task ("buy groceries") appears with the due date you specified. This confirms the integration is working correctly with real data!
If each of these steps works, congratulations – ChatGPT is now successfully talking to Microsoft To Do through Caddey!
You can expand your assistant’s capabilities anytime by connecting more tools in Caddey. If you add new tools or even other apps (say, a Calendar or Notes app), just assign them to your Caddey agent. Your custom GPT will update to include the new actions, allowing you to manage even more from ChatGPT!
Finalize and Deploy Your Custom GPT
Once you're satisfied that everything is functioning, click Save (or Done) to finalize your custom GPT. Your new "To Do Assistant" will now be available in your ChatGPT interface for you to chat with whenever you need it.
Going forward, you can simply start a conversation with this GPT and ask it to manage your tasks. For example, "What are my tasks for today?" or "Mark the grocery task as complete." (if you added a tool for completing tasks) – and the assistant will carry out the request via Caddey.
You’re all set! You have successfully created a ChatGPT assistant that works with Microsoft To Do. Enjoy the convenience of managing your to-do list through natural language, and happy tasking!