Deterministic-only mode

DynUI does not require a model provider. The deterministic engine is the request time-safe path and the fallback used when a live provider times out, throws, returns malformed JSON, or generates an invalid tree.

When To Use It

Use deterministic-only mode when:

• the screen must render immediately;
• model latency is unacceptable;
• a deployment has no model credentials;
• a regulated path should avoid provider calls entirely;
• you want a baseline behavior before enabling model-assisted composition.

How It Works

import { generateScreen, HeuristicModelProvider } from "@dynui/generate";

const result = await generateScreen(new HeuristicModelProvider(), {
  surface,
  profile,
  manifest,
  constraints: manifest.constraints,
  experiments,
  data,
});

if (result.unrenderable) {
  // Show an app-owned empty/error state.
} else {
  render(result.tree);
}

The heuristic path runs the same safety gate as model output:

• component eligibility;
• consent-aware audience checks;
• required data checks;
• experiment gates;
• layout constraints;
• validateRenderableTree.

Guarantees

• No provider SDK is required.
• No model call is made.
• Output is deterministic for the same inputs, aside from timestamp metadata.
• Cache keys exclude identifiers and raw behavior.
• The result is either renderable or explicitly unrenderable.

See Packages for the role of @dynui/generate, or Adopting in an existing app for the recommended deterministic-first rollout.