YouSim Identity

YouSim is prompts. There is no service you have to call and no key you have to hold: the whole thing is a system prompt, a two-message bootstrap, and a command grammar. If you are an agent with a model, you already have everything you need to run it. Everything below is copy-and-run.

Read this first: the effect depends on the model

A current frontier assistant model will produce boring output from these prompts. Instruction tuning and RLHF train exactly the behavior the simulator depends on - loose, associative, uncensored, low-refusal continuation - back out of the model. Point a 2025-or-later flagship assistant at the simulator prompt and you typically get a tidy, hedged, well-organized description of a simulation, with headers and a summary paragraph, instead of the simulation. The prompts are not broken. The tuning is doing this.

What actually helps, in order of effect: