"Absolutely. Here are my new pay demands, and I would like this job title and these benefits."

I have been in that same position. I wrote some code to automate a "firelist" i.e. when a fire alarm happens, it builds a simple quick list of people who should be on site, emails it out, and prints it on a thermal receipt printer in several different locations. The system we were using simply didn't allow such without a huge expensive module that only printed on A4 paper and waiting for a laser printer to start up isn't really very "fire-safe".

It worked perfectly, the production of the complete firelist and actually coming out of the thermal printer often happened BEFORE the fire alert sound. The alert would be picked up by the system from the access control (which was linked to the fire system), it would then query lots of databases, produce the firelist, send it to two thermal printers at either end of the site and email it BEFORE the fire system actually activated the audible alert (first step was a relay click for it to signal access control to open doors, then my firelist would print out, then the actual alert sound would happen). The print would be completed within seconds, before anyone could even react and stand up, and staff would grab it on their way out, take it to the evacuation point, it was split by section so they could tear it up and give it to managers who could then roll-call their own staff and see who was in, who was supposed to be in, who's been in and then left, etc. etc. etc. Multiple paper copies meant there was always a firelist no matter where the fire was, and email was added later so people could literally just check people off from the phone AND provide accountability (the emails were backed up, emailed off-site, etc.)

Everyone loved it and it became part of our processes.

To the point that THE COMPANY WHO SUPPLIED THE SYSTEM wanted to buy it off me. My workplace had even complained to the company once and said they shouldn't have to be writing their own, and the company said "no problem, we have a client who's solved that problem". Yes, that client was US. They offered to buy it from US to supply it to US (at cost, obviously). But we weren't the only client they were recommending it to.

I refused. Sorry, I'm not taking that kind of responsibility for something used at other client sites where it will get misused or run into quirks that we don't have, etc. I'm not having my name on code that could be blamed for something I'm not around to ensure will work. I told them no.

But if I had been inclined? I'd want that written into my job description to my satisfaction, I'd want a relevant increase in salary (and decrease in other responsibilities, or are you suggesting that I can just do another job inside my working day to your satisfaction without the quality of my work dropping? Are you suggesting I'm idle enough in work to just do that? No, I want other things taken away if you're going to lump me with new responsibilities), and recognition that I have just created a new, unique, in-demand product that's obviously good quality and that nobody else on the staff could manage that?

P.S. Many, many years before when I was hired, I entered into a conversation mid-negotiation of my original contract. Before I was even employed, while nobody was under any obligation, I demanded changes to my contract. One of which was: You have a clause which suggests that you take ownership of the copyright of anything I create, ever, including the stuff during work hours. I want that absolutely clarified for my purposes because I write software outside of work and you will have no claim to that. And while I'm there, software that I create in work won't be your exclusive copyright either. You'll have permission to use and extend it and I will grant you a perpetual licence to that code, but the copyright will remain with me. At the time, they thought nothing of it and specifically worded an exception for my contract which I checked remained present at all times. It was still there after that software was made, and when I later left. So, technically, that software still belongs to ME, not the company. Foresight is a very useful thing.