--- url: >- https://adk.nht.io/api/@nhtio/adk/batteries/embeddings/transformers_js/types/interfaces/TransformersJsEmbeddingsAdapterOptions.md description: Constructor options for the transformers.js Embeddings adapter. --- # Interface: TransformersJsEmbeddingsAdapterOptions Defined in: [src/batteries/embeddings/transformers\_js/types.ts:96](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/embeddings/transformers_js/types.ts#L96) Constructor options for the transformers.js Embeddings adapter. ## Remarks Extends the shared [BaseEmbeddingsAdapterOptions](../../../openai/types/interfaces/BaseEmbeddingsAdapterOptions.md) (required `model` + prefix options) with transformers.js pipeline fields. `model` accepts any ONNX feature-extraction model id (e.g. `onnx-community/all-MiniLM-L6-v2-ONNX`) — there is no default. ## Extends * [`BaseEmbeddingsAdapterOptions`](../../../openai/types/interfaces/BaseEmbeddingsAdapterOptions.md).[`BatteryLifecycleHooks`](../../../../llm/transformers_js/helpers/interfaces/BatteryLifecycleHooks.md) ## Properties | Property | Type | Description | Inherited from | Defined in | | ------------------------------------------------------ | ---------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `createPipeline?` | [`CreateTransformersJsEmbeddingsPipeline`](../type-aliases/CreateTransformersJsEmbeddingsPipeline.md) | Override the pipeline factory. Default: `pipeline('feature-extraction', …)` via dynamic import. | - | [src/batteries/embeddings/transformers\_js/types.ts:101](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/embeddings/transformers_js/types.ts#L101) | | `device?` | | `"auto"` | `"gpu"` | `"cpu"` | `"wasm"` | `"webgpu"` | `"cuda"` | `"dml"` | `"coreml"` | `"webnn"` | `"webnn-npu"` | `"webnn-gpu"` | `"webnn-cpu"` | Inference device forwarded to `pipeline()`. Default: transformers.js environment default. | - | [src/batteries/embeddings/transformers\_js/types.ts:103](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/embeddings/transformers_js/types.ts#L103) | | `dimensions?` | `number` | Declared output dimensionality, surfaced via `adapter.dimensions`. Optional metadata for callers that pre-allocate buffers; the battery does not enforce it against responses. | [`BaseEmbeddingsAdapterOptions`](../../../openai/types/interfaces/BaseEmbeddingsAdapterOptions.md).[`dimensions`](../../../openai/types/interfaces/BaseEmbeddingsAdapterOptions.md#property-dimensions) | [src/batteries/embeddings/openai/types.ts:84](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/embeddings/openai/types.ts#L84) | | `documentPrefix?` | `string` | Instruction prefix prepended to inputs embedded with `kind: 'document'`. Unset → no prefix. Most asymmetric models (including Arctic) use no document prefix; exposed for symmetry and the models that do. | [`BaseEmbeddingsAdapterOptions`](../../../openai/types/interfaces/BaseEmbeddingsAdapterOptions.md).[`documentPrefix`](../../../openai/types/interfaces/BaseEmbeddingsAdapterOptions.md#property-documentprefix) | [src/batteries/embeddings/openai/types.ts:79](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/embeddings/openai/types.ts#L79) | | `dtype?` | | `"auto"` | `"fp32"` | `"fp16"` | `"q8"` | `"int8"` | `"uint8"` | `"q4"` | `"bnb4"` | `"q4f16"` | `"q2"` | `"q2f16"` | `"q1"` | `"q1f16"` | Quantization/precision dtype forwarded to `pipeline()`. | - | [src/batteries/embeddings/transformers\_js/types.ts:105](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/embeddings/transformers_js/types.ts#L105) | | `isAvailable?` | () => `boolean` | Override the availability probe. Default: `true` whenever the peer is importable (env-neutral). | - | [src/batteries/embeddings/transformers\_js/types.ts:125](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/embeddings/transformers_js/types.ts#L125) | | `model` | `string` | Model id to embed with. **Required, no default.** For OpenAI this is e.g. `text-embedding-3-small`; for WebLLM it is an MLC embedding model id (e.g. `snowflake-arctic-embed-m-q0f32-MLC`). | [`BaseEmbeddingsAdapterOptions`](../../../openai/types/interfaces/BaseEmbeddingsAdapterOptions.md).[`model`](../../../openai/types/interfaces/BaseEmbeddingsAdapterOptions.md#property-model) | [src/batteries/embeddings/openai/types.ts:67](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/embeddings/openai/types.ts#L67) | | `modelSource?` | [`TransformersJsEmbeddingsModelSource`](../type-aliases/TransformersJsEmbeddingsModelSource.md) | Custom model-source resolver (OPFS / separate source / bundled bytes). When set, model files load through it behind the global-`env` mutex; otherwise straight from HF (unchanged). See [TransformersJsEmbeddingsModelSource](../type-aliases/TransformersJsEmbeddingsModelSource.md). | - | [src/batteries/embeddings/transformers\_js/types.ts:121](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/embeddings/transformers_js/types.ts#L121) | | `normalize?` | `boolean` | L2-normalise the embeddings (default `true`). | - | [src/batteries/embeddings/transformers\_js/types.ts:109](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/embeddings/transformers_js/types.ts#L109) | | `onCompiling?` | [`BatteryLifecycleCallback`](../../../../llm/transformers_js/helpers/type-aliases/BatteryLifecycleCallback.md) | Engine/graph/shader compilation after download, before the first token. A COARSE marker: the on-device runtimes (LiteRT `Engine.create`, transformers.js `from_pretrained`) expose the boundary — download done, opaque WebGPU/WASM graph build about to run — but NOT a progress stream, so `progress` is usually absent. Often the slowest part of a cold start; without this it was invisible. | [`BatteryLifecycleHooks`](../../../../llm/transformers_js/helpers/interfaces/BatteryLifecycleHooks.md).[`onCompiling`](../../../../llm/transformers_js/helpers/interfaces/BatteryLifecycleHooks.md#property-oncompiling) | [src/batteries/llm/chat\_common/lifecycle.ts:95](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/llm/chat_common/lifecycle.ts#L95) | | `onComplete?` | [`BatteryLifecycleCallback`](../../../../llm/transformers_js/helpers/type-aliases/BatteryLifecycleCallback.md) | After the turn's output is parsed + persisted, before `ack` (fires per turn). | [`BatteryLifecycleHooks`](../../../../llm/transformers_js/helpers/interfaces/BatteryLifecycleHooks.md).[`onComplete`](../../../../llm/transformers_js/helpers/interfaces/BatteryLifecycleHooks.md#property-oncomplete) | [src/batteries/llm/chat\_common/lifecycle.ts:105](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/llm/chat_common/lifecycle.ts#L105) | | `onError?` | [`BatteryLifecycleCallback`](../../../../llm/transformers_js/helpers/type-aliases/BatteryLifecycleCallback.md) | A load or generation failure (paired with `nack`). | [`BatteryLifecycleHooks`](../../../../llm/transformers_js/helpers/interfaces/BatteryLifecycleHooks.md).[`onError`](../../../../llm/transformers_js/helpers/interfaces/BatteryLifecycleHooks.md#property-onerror) | [src/batteries/llm/chat\_common/lifecycle.ts:107](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/llm/chat_common/lifecycle.ts#L107) | | `onGenerating?` | [`BatteryLifecycleCallback`](../../../../llm/transformers_js/helpers/type-aliases/BatteryLifecycleCallback.md) | The generate call is in progress (fires per turn). Fires once immediately before the provider call for most engines; engines that stream per-step generation progress (e.g. a diffusion denoise loop) fire it REPEATEDLY during generation, each carrying a `progress` in `0..1`. | [`BatteryLifecycleHooks`](../../../../llm/transformers_js/helpers/interfaces/BatteryLifecycleHooks.md).[`onGenerating`](../../../../llm/transformers_js/helpers/interfaces/BatteryLifecycleHooks.md#property-ongenerating) | [src/batteries/llm/chat\_common/lifecycle.ts:103](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/llm/chat_common/lifecycle.ts#L103) | | `onInitProgress?` | `ProgressCallback` | Called with model-load progress reports while weights download/compile. | - | [src/batteries/embeddings/transformers\_js/types.ts:123](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/embeddings/transformers_js/types.ts#L123) | | `onLifecycle?` | [`BatteryLifecycleCallback`](../../../../llm/transformers_js/helpers/type-aliases/BatteryLifecycleCallback.md) | Fires on EVERY phase transition (the firehose). | [`BatteryLifecycleHooks`](../../../../llm/transformers_js/helpers/interfaces/BatteryLifecycleHooks.md).[`onLifecycle`](../../../../llm/transformers_js/helpers/interfaces/BatteryLifecycleHooks.md#property-onlifecycle) | [src/batteries/llm/chat\_common/lifecycle.ts:86](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/llm/chat_common/lifecycle.ts#L86) | | `onLoading?` | [`BatteryLifecycleCallback`](../../../../llm/transformers_js/helpers/type-aliases/BatteryLifecycleCallback.md) | Weights/runtime loading — may fire repeatedly with `progress` as the provider reports it. | [`BatteryLifecycleHooks`](../../../../llm/transformers_js/helpers/interfaces/BatteryLifecycleHooks.md).[`onLoading`](../../../../llm/transformers_js/helpers/interfaces/BatteryLifecycleHooks.md#property-onloading) | [src/batteries/llm/chat\_common/lifecycle.ts:88](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/llm/chat_common/lifecycle.ts#L88) | | `onReady?` | [`BatteryLifecycleCallback`](../../../../llm/transformers_js/helpers/type-aliases/BatteryLifecycleCallback.md) | Engine/pipeline resolved and cached, before the first generation. | [`BatteryLifecycleHooks`](../../../../llm/transformers_js/helpers/interfaces/BatteryLifecycleHooks.md).[`onReady`](../../../../llm/transformers_js/helpers/interfaces/BatteryLifecycleHooks.md#property-onready) | [src/batteries/llm/chat\_common/lifecycle.ts:97](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/llm/chat_common/lifecycle.ts#L97) | | `pipeline?` | `FeatureExtractionPipeline` | A pre-built pipeline. When provided, the battery uses it directly and skips lazy creation. | - | [src/batteries/embeddings/transformers\_js/types.ts:99](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/embeddings/transformers_js/types.ts#L99) | | `pooling?` | [`TransformersJsPooling`](../type-aliases/TransformersJsPooling.md) | Pooling method (default `'mean'`). | - | [src/batteries/embeddings/transformers\_js/types.ts:107](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/embeddings/transformers_js/types.ts#L107) | | `poolingOwner?` | [`TransformersJsPoolingOwner`](../type-aliases/TransformersJsPoolingOwner.md) | Who pools + normalizes (default `'engine'` — today's behavior, byte-identical). Set `'battery'` to pool + L2-normalize in deterministic shared JS for tighter node↔browser parity. See [TransformersJsPoolingOwner](../type-aliases/TransformersJsPoolingOwner.md). | - | [src/batteries/embeddings/transformers\_js/types.ts:115](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/embeddings/transformers_js/types.ts#L115) | | `queryPrefix?` | `string` | Instruction prefix prepended to inputs embedded with `kind: 'query'`. Unset → no prefix. For Snowflake Arctic Embed, the documented value is `'Represent this sentence for searching relevant passages: '`. | [`BaseEmbeddingsAdapterOptions`](../../../openai/types/interfaces/BaseEmbeddingsAdapterOptions.md).[`queryPrefix`](../../../openai/types/interfaces/BaseEmbeddingsAdapterOptions.md#property-queryprefix) | [src/batteries/embeddings/openai/types.ts:73](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/embeddings/openai/types.ts#L73) |