There are now four categories of moddable things: World presets, survival bars, prompts, and event checks. With this also comes the "open sourcing" of almost all prompts and event checks.
World presets: You can add new game world presets to the defaults, and share them as mods. This is the simplest kind of mod.
Survival bars: You can make your own survival bars with a limited API of how they function in the world, e.g. whether they drain over time. You can also specify your own event checks to use to increase or decrease said survival bar (more on that below), as well as the event checks for whether a consumable heals that survival bar. The original 3 survival bars have been migrated to this new system so you can use them as examples (located in the "Default" directory) for how the survival bar mod config works.
Prompts: All prompts are now visible in the "prompts" directory and can be modified based on how you see fit. Some prompts may be outdated because they were engineered to play nice with the 125M, which is becoming less used for general text generation. There may be some low-hanging fruit, and if there are mods that improve them, I may incorporate them into the base game. For example, to avoid the "small," issue, maybe we can start separating entities by semi-colon, period, newline, or numbered list, instead of commas.
Event checks: Using gpt_testing.exe and my_gpt_calibration.exe, you can create your own event checks. Each event check must go through a "calibration" process, invented by yours truly, to make sure it plays nice with each AI model. This is where you provide positive and negative examples to try to make it hone in on a desirable threshold value. You should run calibration for at least the top 3 most used models as recommended by the instructions. For less-used models, the game will try to automatically run calibration for the user before running the model. It is not always easy to find event check prompts that work well, because what seems to work in calibration might not be great in the actual game. However, as with prompts, if people discover an absolute improvement, I will likely incorporate it into the base game.
Instructions on how to mod are inside the ai-roguelite-config/my-mods directory. It is not that intuitive at the moment. Better instructions and validation are forthcoming. Please note it's not recommended to modify the "Default" directory because it's the base game which will be updated; it's preferable to make a mod instead. Overall, making mods is intended for enthusiasts, and people who just want to play the game with mods can subscribe to them on the AI Roguelite steam workshop page, which will hopefully be more populated as time goes on.