deepseek-ai/deepseek-harness · error · MaterializeError

reading the value threw: ${renderThrown(error)}

Error message

reading the value threw: ${renderThrown(error)}

What it means

Error "reading the value threw: ${renderThrown(error)}" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/workflow/workflow-worker-thread/src/realm.ts:74

 * returned unchanged; nested `undefined` and values JSON cannot represent losslessly fail
 * with the offending path. Property accessors run normally, and a throwing read is wrapped
 * with its rendered failure.
 *
 * @param value - the realm value to materialize.
 * @param root - the path label for the root value (error messages).
 * @returns the host-realm copy (plain objects/arrays/scalars only).
 * @throws {@link MaterializeError} for unsupported values, cycles, sparse arrays, exotic
 *   prototypes, or property reads that throw.
 */
export function materializeFromRealm(value: unknown, root = 'value'): unknown {
  if (value === undefined) return undefined
  try {
    return materialize(value, root, new Set())
  } catch (error: unknown) {
    if (error instanceof MaterializeError) throw error
    // A property read ran script code that threw; total-ize it so callers can
    // keep the narrow MaterializeError contract.
    throw new MaterializeError(root, `reading the value threw: ${renderThrown(error)}`)
  }
}

function materialize(value: unknown, path: string, seen: Set<object>): unknown {
  switch (typeof value) {
    case 'boolean':
    case 'string':
      return value
    case 'number': {
      if (!Number.isFinite(value)) throw new MaterializeError(path, 'non-finite numbers are not JSON data')
      return value
    }
    case 'bigint':
      throw new MaterializeError(path, 'bigints are not JSON data')
    case 'function':
      throw new MaterializeError(path, 'functions are not plain JSON data')
    case 'symbol':
      throw new MaterializeError(path, 'symbols are not plain JSON data')

View on GitHub (pinned to b150a551b8)

Solutions

1. Remove throwing getters or proxies from the returned value; materialize plain data before returning it from the workflow.

When it happens

Trigger: Thrown at packages/workflow/workflow-worker-thread/src/realm.ts:74 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of deepseek-ai/deepseek-harness@b150a551b8 (2026-08-24). Data as JSON: /api/errors/c3484873565339bd. Report an issue: GitHub.