Primitives· Last updated 2026-09-21

Jev Choice questions

A Choice is the System One question for “which of these?” You supply a map of option name → description (null if the name is enough). The API allows up to 255 options.

The answer includes:

• choice — the highest-probability option.
• probabilities — every option mapped to a float. They sum to 1.
• confidence — a 0–1 summary of how peaked that distribution is.

Minimal shape

{
  "department": {
    "type": "choice",
    "instructions": "Which team should handle this?",
    "criteria": {
      "billing": "Payments, invoicing, refunds",
      "technical": "Bugs, outages, integrations",
      "sales": "Pricing, upgrades, new accounts"
    }
  }
}

TypeSafe’s launch post notes that high-cardinality Choices use a two-stage system (score independently, then choose), which can occasionally slow a call. That is their description of jev behavior at high cardinality, not a latency SLA from this site.

Relative, not absolute

A Choice settles which option wins among the set. Separate Nouls on each option ask whether each property is true in absolute terms. Those can all be low. The skill-suggestion cookbook uses both: Choice to pick a skill, Nouls to decide whether to suggest one at all.

Do not carry a threshold tuned on a Noul over to a Choice. The jaggedness page shows they are not interchangeable.

When Choice is the wrong tool

• You need “how much,” not “which.” Use Score.
• You need “is this true?” Use Noul.
• You need a value extracted from text (an email address, a date). Extract candidates in code, then Choice among them — or use the extraction cookbooks.