A photo of a bill now becomes an Outlook reminder two working days early
A custom GPT that reads a photographed bill and places a reminder in Outlook two working days before it is due.
This student took an everyday chore, remembering when bills are due, and handed it to an assistant they built themselves. Along the way they wired ChatGPT to Microsoft Graph through Azure and OAuth, and pushed through the error messages until it worked. It is a clear picture of what one focused build can look like.
Before
Bills arrived on paper or as documents, and keeping track of each due date was a manual job. Getting an AI to act on their calendar meant working with tools like Azure, Entra ID and OAuth, which are not simple to set up. The idea was clear, but the path from a photo to a calendar entry was not.
“Take a photo or attach a document of a bill and it will put a reminder in my Outlook calendar 2 working days before it is due.”
In their own words
The turning point
During the program they broke the build into steps. They wrote a custom GPT prompt with step-by-step instructions, then tested until it could consistently produce the JSON and permissions needed. When OAuth 2.0 kept throwing error messages, they troubleshot the Azure setup until ChatGPT could connect.
After
They now have a working custom GPT called Bill Reminder Assistant. They upload a photo or PDF of a bill, check a one-screen confirmation, and the assistant creates an Outlook event with the amount, due date and payment options. The event is placed two working days before the bill is due.
What it lets people do
It turns a piece of paper into a scheduled reminder without typing anything in by hand. The due date, amount and payment details land in the calendar note, so everything needed to pay is in one place at the right time.
What they learned
A big, technical idea becomes manageable when it is taken one step at a time and tested along the way. Error messages are part of the work, not a sign to stop, and getting through them is what turns a prompt into a tool that actually acts.
“Created and troubleshooted setup of OAuth 2.0 in Chat GPT to utilise setup in Azure as was getting error messages.”
In their own words
See the work
Bill Reminder Assistant was built during AI Mastery.
Read the full submission
Written 14 February 2026 Submitted by the storyteller
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