Been a weird week to be paying attention to OpenAI, and I'm writing this Friday afternoon with one eye on the news ticker because something is very obviously happening over there right now that nobody outside the building fully understands yet. Not touching that until it settles. What I actually want to write about is something smaller and, honestly, more useful to me day to day: I spent most of last weekend building custom GPTs, and it's changed how I use ChatGPT more than any update since the original GPT-4 launch.
Quick backstory for anyone who missed it. At DevDay on November 6th, OpenAI rolled out GPT-4 Turbo, which bumps the context window to 128k tokens (thats something like 300 pages of text in one conversation, which is absurd when you say it out loud) and pushed the knowledge cutoff up to April 2023. Pricing dropped too: $0.01 per 1K input tokens and $0.03 per 1K output tokens if youre using the API, which is roughly a third of what the old GPT-4 cost. But the part that actually reached regular Plus subscribers like me this week is the "GPTs" feature, meaning you can build your own configured version of ChatGPT without writing a line of code.
I know, I know, the naming is a disaster. GPT-4, GPT-4 Turbo, and now "GPTs" as a totally separate plural noun. Whoever signed off on that deserves a stern email.
Anyway, how it actually works: theres a Create tab where you just describe what you want in plain English, and a Configure tab where you get more granular. Name, description, a big instructions box where you write the system prompt, an optional file upload for "knowledge" (I dropped in a folder of my own old blog posts for one of them), and toggles for web browsing, DALL-E image generation, and code interpreter. You can also wire up custom Actions that hit an external API if you want it doing more than chatting, though I didnt bother with that part yet.
The first one I made was dumb but useful: I fed it eleven years of this blogs archive and told it to write in my voice when I give it a topic. It's not perfect, it leans a little too hard on em dashes for my taste and it loves starting sentences with "honestly," which apparently I do a lot more than Id like to admit. But as a first-draft generator for posts like this one, its saved me a solid hour this week alone.
The second one is more practical. My mother-in-law is visiting for Thanksgiving and every year theres a group text negotiation over who's bringing what. I built a GPT that just knows our usual dishes, our allergies (my brother-in-law and shellfish, never again after 2019), and can spit out a shopping list scaled to however many people are coming. Took maybe fifteen minutes to set up including testing. Would I have built a whole app for this? Absolutely not. Would I spend fifteen minutes on it? Apparently yes.
A few rough edges worth flagging if you're going to try this yourself. The knowledge upload has a file size limit thats stingier than youd expect, so if you're feeding it a big archive youll want to trim it down first rather than dumping everything in and hoping. The instructions box also has a length cap, and it's easy to blow past it if youre the type (me) who writes instructions the way you'd explain something to a very literal-minded intern. Shorter and more direct works better than longer and more thorough, which took me a couple of tries to actually accept.
There's also a GPT Store coming, supposedly, where you'll be able to publish and even get paid for GPTs other people use. Nothing live yet as far as I can tell, just the promise of it during the keynote. I'll believe the payout part when I see a number in an account.
None of this required touching the API or writing code, which is the actual headline here for anyone who's been intimidated by that stuff. If you've got a ChatGPT Plus subscription already, the GPT builder is sitting right there under the "Explore" section, and it's worth the twenty minutes it takes to make something dumb just to see how the pieces fit together. Start small. Mine started with a Thanksgiving grocery list and I'm already thinking about what to build next.