laya_dart

Laya is an open-source System 1 decision model. It evaluates a state against typed questions and returns choices, scores, and yes/no probabilities.

laya_dart runs Laya locally in Flutter or Dart. It uses the onnxruntime_v2 Flutter FFI wrapper, backed by ONNX Runtime, to execute the model on the device.

Install

dependencies:
  laya_dart: ^0.0.1

Use

import 'package:laya_dart/laya_dart.dart';

// Downloads uppppiiiii/laya_onnx once, then reuses the verified cache.
final laya = await Laya.load();
// Or: await Laya.load('/path/to/local/laya-bundle'); // No network access.
final result = await laya.predictAsync(
  'The customer was charged twice and wants a refund.',
  {
    'department': LayaQuestion.choice(
      instructions: 'Which team should handle this message?',
      criteria: {
        'billing': 'payments and refunds',
        'technical': 'bugs and outages',
        'other': 'anything else',
      },
    ),
    'urgency': LayaQuestion.score(
      instructions: 'How urgently should this message be handled?',
      criteria: ['not urgent', 'soon', 'urgent', 'critical'],
    ),
    'refund': LayaQuestion.noul(
      instructions: 'Does the customer request a refund?',
    ),
  },
);
await laya.close();

Laya.predict is synchronous. Laya.predictAsync queues native inference on a worker isolate. choice selects a labelled option, score selects an ordered level, and noul returns a yes/no probability. Loading and tokenization currently run on the calling isolate; profile their UI impact before shipping.

Await laya.close() to drain accepted requests and release the session. Repeated closes share the same completion. New requests after close and synchronous inference while async requests are pending are rejected. The shared ORT environment remains process-resident so closing one session cannot invalidate another. Native inference has no timeout/cancellation: a caller-side timeout does not stop it.

Hugging Face model and pinned downloads

Laya.load() downloads the default uppppiiiii/laya_onnx bundle from Hugging Face at the immutable commit b3930f0f1aed41bb6a4493eafdca9d19ee0d86f5. It includes laya.onnx, its required laya.onnx.data external weights, rl_agent_config.json, and the tokenizer files. The bundle requires roughly 1.7 GB of download/storage.

Every downloaded file is pinned to its SHA-256 checksum. The package downloads into application-support storage once, verifies it, and reuses that versioned cache on later runs. To stay fully offline or load a different compatible bundle, pass its directory explicitly: Laya.load('/path/to/local/laya-bundle').

Downloads stream to staging and publish into a versioned directory only after checksum validation. Cached files are checked again before reuse. Old versions are retained; corruption produces an actionable error. ensureDownloaded returns the actual version directory; use that path, not the cache root. Process crashes can leave unused staging directories, which may be removed once no downloads are running.

For local model download, ONNX conversion, and bundle setup, see the local model guide.

License

The laya_dart package is released under the MIT License. Laya model weights retain the model publisher's license.