Designing with typed decisions

typed-lm works best when you keep the control in your code and give the model narrow, structured decisions. This chapter is a short design guide.

Keep code in control

The model answers questions; your code decides what to do with the answers. Do not ask the model to perform multi-step reasoning or to choose a whole workflow. Ask for the individual judgments, then combine them with ordinary logic.

---
accTitle: Code controls the workflow, the model supplies decisions
accDescr: The application decomposes a workflow into atomic questions, the model returns typed decisions, and the code combines them.
---
flowchart LR
  workflow["business workflow"]:::neutral
  policy["your code<br/>weights · thresholds · rules"]:::primary
  atomic["atomic questions"]:::accent
  model["typed-lm"]:::accent
  decisions["typed decisions"]:::success
  outcome["action · route · escalate"]:::success

  workflow --> policy
  policy --> atomic --> model --> decisions --> policy
  policy --> outcome

  classDef primary fill:#ede9fe,stroke:#7c3aed,color:#3b0764,stroke-width:1.5px
  classDef accent fill:#dbeafe,stroke:#2563eb,color:#0c4a6e,stroke-width:1.5px
  classDef success fill:#d1fae5,stroke:#059669,color:#064e3b,stroke-width:1.5px
  classDef neutral fill:#f4f4f5,stroke:#a1a1aa,color:#18181b,stroke-width:1.5px

Decompose, do not compound

A compound question forces the model to weigh several factors at once, which reduces reliability. Decompose it into atomic questions and combine the results in code.

Instead of “rate this startup pitch”, ask separately about market size, technical feasibility and differentiation. Combine the scores with your own formula, so priorities can change without rewriting a prompt.

Ask one thing per question

• Specific — “The customer is eligible for a full refund under the store policy.” is better than “assess this case.”
• Closed — the answer set is declared in criteria.
• Grounded — the facts it needs are in the state or the context.

Match the primitive to the decision

Use confidence to decide whether to act

Treat confidence (for choice and score) and the noul value as gates. Act automatically only when the model is sure; route the uncertain band to a human or a slower path. See Confidence.

A worked decomposition

A support ticket must be refunded, routed and prioritized. Do not ask one question that returns all three. Ask three:

1. Noul — is the customer eligible for a full refund?
2. Choice — which department owns this case?
3. Score — how urgent is it?

Then combine in code: refund only when the noul exceeds your threshold and the amount is within policy; route to the chosen department; escalate when urgency is high. Every rule lives in code, where you can test and change it.

Next steps

• Patterns — reusable architectures.
• Cookbooks — end-to-end examples.
• Preparing datasets — teach these decisions.