I’ve created a script that helps you easily check if any pets or items in your current trade are also involved in other active trades.
How did you come up with the idea for this?
While browsing through suggestions, I came across this one from 2014. After reading through it, I thought, "Hey, I could probably script a solution for this!" So, over the course of a week, I put it together. A huge thanks to Celozon, spaceinmyhead, and Simon for helping me test it. Of course, I also got approval from Nick since we don't allow scripts that offer users an unfair advantage—but this is more like a helpful reminder than something that affects gameplay.
How does it work?
First, head over to your trading center and click on any of your current trades. If any pets or items on your side are also part of another active trade, a warning message will pop up with a direct link to the overlapping trade and the pet/items involved. If there’s no overlap, no message will appear. You can see an example of the warning message below:


WARNING
Please keep in mind that pets and items on CS are fundamentally different. Pets have unique IDs, meaning each pet is one-of-a-kind. When you search for a pet ID, it's the only version of that pet, and trading it away will automatically cancel any other trades containing that same pet. Items, on the other hand, do not have unique IDs. If you have the same item in two different trades, it won't automatically cancel unless you only have one copy of the item.
How do I install it?
- 1. Download and install the TamperMonkey extension for your browser. I've only tested this on Chrome, so if anyone can confirm it works on other browsers, that’d be fantastic!
2. Once you have TamperMonkey, go to this link and install the script: Check for Pet and Item Matches in Other Trades
I’m unsure if there’s a way to get this working on mobile, so if anyone has ideas or suggestions, I’d love to hear them!
Please keep in mind that only a few people have tested it so far. If you encounter any bugs, feel free to post them below, and I’ll work on getting them fixed.