Run with Browser AI · Chapter 12

Run Chapter 12: Model Contract Compatibility Laboratory

Compare versioned Prompt API option profiles, preserve exact lifecycle failures and distinguish operator-labelled browser configurations from browser-attested model identity.

← Read The Browser Manages the Model
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Chapter experiment

The Browser Manages the Model

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What this experience knows

This experience is grounded in Chapter 12 and treats the browser-managed model as an abstraction boundary with observable effects.

Identity boundary

The operator can label a browser configuration and record its exact build. Neither value is model attestation. The Prompt API does not identify the model that produced a response, so exports keep source: operator-supplied and browserAttested: false.

Compatibility boundary

Each creation policy has a stable profile ID, explicit options and a SHA-256 option fingerprint. Results from different profiles are not silently pooled.

Lifecycle boundary

Availability, session creation, acquisition-monitor callbacks, prompting and destruction are separate observations. An available result does not certify that creation or prompting will succeed.

Progress boundary

The API event is preserved as model.download.progress, but the interface calls it an asset-monitor callback. A zero-to-one callback sequence does not by itself prove a new download or identify an asset.

Probe boundary

The compatible suite uses only profiles named by the observed runtime error as acceptable. The non-deterministic profile is isolated behind a separate button. Whether it is accepted or rejected is evidence about this browser configuration, not a universal assertion about all implementations.

Behavioral boundary

Creation success is not feature correctness. Compatible profiles run the same fixed fixture so lifecycle compatibility and basic behavioral continuity can be compared without changing the task.

This laboratory runs a fixed feature contract through several explicitly versioned Prompt API option profiles. It records availability, creation, progress callbacks, prompt behavior and destruction separately, because a browser-managed runtime can accept one boundary and reject the next.

The deliberately non-deterministic profile is never included in the compatible suite. It runs only through its own explicit probe and preserves the current browser’s exact acceptance or rejection rather than treating a historical error as a permanent universal rule.