Uncredited Spreadsheet Idea

You spent the weekend building a spreadsheet that fixed a reporting problem at work. On Monday, a colleague presented it to the team as their own idea, and your supervisor praised them. You like this colleague and do not want conflict, but you feel overlooked. Speak to your colleague: explain how you feel and suggest how to correct it.

Hey, can I grab you for a quick chat? I wanted to mention something about Monday's meeting. When you presented the reporting spreadsheet, it came across as your idea, and I was a little surprised, because I built it over the weekend. I'm sure you didn't mean it that way, and I'm glad the team found it useful. Would you mind sending a short note to our supervisor mentioning that we worked on it together? Going forward, maybe we could agree on how we present shared work. Thanks for hearing me out.