Ollama's new /v1/systemone endpoint isn't a chat completion with a JSON wrapper. It's a different contract.
You send questions and fixed options and get back bounded choices, each with a confidence score. There's no streaming and no tools. In v0.35.x it's local GGUF models only, and cloud tags return a 400.
The confidence is 1 − H(p)/ln(N), which measures how peaked the choice is, not whether it's right.
What you can check yourself, and what's already changing in v0.40:


A Decision Endpoint Is Not a Chat Completion: Ollama’s /v1/systemone and What You Can Verify
Ollama’s /v1/systemone returns choices, probabilities, and scores instead of chat text. A decision endpoint is a different contract from /v1/chat...

