# Configure Render Timeouts
URL: /runtime/guides/render-timeouts



Use `operationTimeout` for wall-clock deadlines on document description, evaluation, view rendering, and exports. All values are milliseconds; zero disables enforcement. Direct transcodes have a separate deadline.

## Prerequisites [#prerequisites]

Use an isolated worker or remote transport capable of enforcing a deadline. Same-isolate `inProcessTransport` rejects a positive timeout because synchronous work also blocks the client's timer. See [Transport API](/runtime/api/transport).

## Steps [#steps]

### 1. Configure the client [#1-configure-the-client]

```typescript
import { createRuntimeClient, isOperationTimeoutError } from '@taucad/runtime/client';
import { createWebWorkerClientOptions } from '@taucad/runtime/transport/web';

const clientOptions = createWebWorkerClientOptions({
  createWorker: () => new Worker(new URL('./runtime.worker.ts', import.meta.url), { type: 'module' }),
});
const client = createRuntimeClient({ ...clientOptions, operationTimeout: 60_000 });
const document = client.open({ source: { path: 'main.ts' } });

try {
  const outcome = await document.evaluation();
  if (!outcome.superseded) {
    console.log(outcome.evaluation.success);
  }
} catch (error) {
  if (isOperationTimeoutError(error)) {
    console.warn(error.code, error.phase);
  } else {
    throw error;
  }
} finally {
  document.close();
  await client.shutdown();
}
```

The worker entry declares plugins with `defineRuntime` and calls `serveWebWorkerRuntime`; see [Worker Model](/runtime/concepts/worker-model). Keep reusable client options at module scope, and materialize a fresh client for each independent lifetime.

### 2. Change future deadlines [#2-change-future-deadlines]

```typescript
import type { RuntimeClient } from '@taucad/runtime/client';

export function changeDeadlines(client: RuntimeClient): void {
  client.setOperationTimeout(120_000);
  client.setTranscodeTimeout(30_000);
}
```

Both setters return synchronously, reject negative/nonfinite durations, and affect subsequently admitted operations. They do not change work already in flight. Direct conversion defaults to `60_000`; document operations default to zero.

### 3. Distinguish failure from supersession [#3-distinguish-failure-from-supersession]

Deadline expiry rejects the matching promise locally with `OperationTimeoutError`, including without shared memory. Supersession instead resolves as `{ superseded: true }`. Explicit abort uses `OperationAbortedError`; transport loss or termination uses `RuntimeTerminatedError`.

The runtime requests cooperative cancellation. A blocked isolated host that cannot settle during bounded recovery may be terminated. Recreate its client from the stable options spec after termination; explicitly reopen the intended source. The runtime does not replay model operations automatically.

## Variations [#variations]

Electron uses its renderer/main/utility transport ownership to terminate a blocked utility process. Use `createElectronClientOptions` from `@taucad/runtime/electron/renderer` rather than passing utility IDs or raw ports to the client.

For native/WASM kernels, shared abort state can be checked inside synchronous loops. Kernel authors use the existing operation-scoped services signal and cooperative abort helpers; see [Cooperate with Cancellation](/runtime/guides/cooperate-with-cancellation).

## Related [#related]

* [Handle Errors](/runtime/guides/error-handling)
* [Client API](/runtime/api/client)
* [Worker Model](/runtime/concepts/worker-model)