# ADR 0002: Run ONNX with one thread inside the Piper worker

## Decision

Configure ONNX Runtime Web to use one thread and stop backend initialization after 60 seconds. Piper already runs in a dedicated worker, so ONNX does not need to create another worker pool.

## Context

On iPad, the threaded ONNX WASM file downloaded fully, but the runtime did not report that initialization had completed. Nested worker startup and shared-memory setup are a likely compatibility boundary on mobile Safari. The available production assets currently include the threaded ONNX build.

## Consequences

This removes ONNX's additional worker pool and bounds initialization failures with a visible error. It may reduce inference throughput on desktop devices. CI and Kubernetes release verification must confirm that Piper still initializes and speaks on supported browsers; iPad acceptance remains a manual device check.