MediaPipeOnDeviceLlm

True when this backend accepts an LlmPart.Image in generate. False = text-only.

Honest self-report for a capability-aware caller: whether this backend genuinely streams tokens and accepts images, which GenerationConfig fields it reads, and — when it can't run — the real AiFailure reason instead of a bare false. Default answer is conservative (no streaming, no honored config) and derives AiCapabilities.unavailableReason from isAvailable alone; a backend with a more specific gate (model residency, OS feature status) overrides this to report why.

Runs prompt on-device. Success carries the model's text; failure names why via AiFailure.

Multimodal entry point. Default maps a single LlmPart.Text onto generate (String) so every existing text-only actual (MediaPipe, Foundation Models, jvm) keeps working with zero changes. Backends that accept images (ML Kit GenAI) override this directly.

Streaming variant of generate. Default replays the single-shot result as one emission so every existing actual keeps working with zero changes; backends with native token streaming (ML Kit GenAI, MediaPipe) override this directly. CompositeOnDeviceLlm overrides both overloads too, so streaming through it reaches whichever backend it picked, not this default.

Cheap, synchronous floor — true only when the platform could run inference. NOT the authoritative runtime check (model residency is async); generate still guards internally.