Glossary
The words that come up when you read about System One AI models, defined once and linked from everywhere else on the site.
C
- Calibrated ProbabilityA calibrated probability is a number from a model that means what it says: across all the answers given at 80%, about 80% are right.
- CalibrationCalibration is the match between a model's stated probabilities and how often it turns out to be right.
- ChoiceA Choice is a System One question type for selecting one option from a defined set.
- Composite scoringComposite scoring is one of TypeSafe's documented patterns, described as "Combine several dimensions of analysis into a single score." You ask a separate question about each dimension, then your own code weights and combines the answers.
- ConfidenceConfidence is a number from 0 to 1 that TypeSafe computes from the probability distribution an answer already carries.
- Confidence GatingConfidence gating is the practice of branching your code on a model's confidence value as well as on its answer.
D
E
H
I
J
N
Q
R
S
- ScoreA Score is a System One question type that rates content against ordered, descriptive levels, minimum 2 and maximum 10.
- Speculative fan-outSpeculative fan-out is one of TypeSafe's documented patterns: "Send many questions in a single call, including speculative ones, and let your code decide what's relevant." Because questions are evaluated in parallel, extra questions typically cost no extra latency, so you ask ahead instead of making a second round trip.
- StateState is TypeSafe's word for the content you hand a System One model: the ticket, document, transcript or JSON object the questions are asked about.
- Structured outputsStructured outputs is the existing technique for making a language model emit valid JSON: constrain decoding to a schema so every generated token keeps the output parseable.
- System One ModelA System One model is a class of AI models built to make fast, structured decisions that software can use directly.
- System Two ModelSystem Two model is a contrast term, not a product.
T
- Thinking, Fast and SlowThinking, Fast and Slow is Daniel Kahneman's 2011 book (Farrar, Straus and Giroux) describing two modes of human thought: a fast, automatic System 1 and a slow, deliberate System 2.
- Typed outputTyped output is a model answer that arrives already shaped as a value your code can use, such as an enum member or a probability between 0 and 1.
- TypeSafe AITypeSafe AI is the San Francisco company that coined the term System One model and shipped the first one, Jev, on 2026-09-15.