Jev Noul

Noul is the smallest Jev primitive: one statement, one probability.

Request

{
  "is_urgent": {
    "type": "noul",
    "instructions": "Does this convey urgency?",
    "criteria": {
      "true": "Explicitly time-sensitive",
      "false": "No urgency expressed"
    }
  }
}

criteria is optional. Use it when the yes/no boundary is subtle.

Response

{
  "type": "noul",
  "noul": 0.95
}

There is no confidence key. noul itself is the uncertainty signal.

Phrase high as yes

“Is the customer angry?” is fine. “Is the customer not calm?” stacks a negation. Official jaggedness notes say contradictory true/false mappings perform worse.

Do not ask “Is this candidate strong in Python?” if you cannot define strong. Either tighten the Noul (“Does the resume state the candidate used Python at work?”) or switch to a Score.

Thresholds live in code

if answers["refund_requested"].noul > 0.9:
    start_refund_review()
elif answers["refund_requested"].noul < 0.15:
    close_as_not_refund()
else:
    queue_human()

The cutoffs are yours. Official cookbooks show routing uncertain nouls to humans while keeping the raw value visible.

When to use Noul

PII present? Refund requested? Prompt injection in this passage? Same-day risk? Skill needed at all?

TypeSafe's skill-suggestion cookbook uses Nouls and a Choice on the same shortlist: Choice picks a name, Nouls decide whether to suggest anything.

When not to use Noul

• Three plus destinations → Choice
• A spectrum → Score
• Counting how many items match → iterate in code, one Noul each, then sum

Common mistakes

• Using Noul as a 0–1 quality slider.
• Assuming P(refund) + P(not refund) = 1 across two questions. Official notes say that identity is not guaranteed.
• Copying a Noul threshold onto a yes/no Choice.

More patterns: examples and How Jev works.