deepseek-ai/deepseek-harness · error

subagent: ${name} listener threw: ${renderThrown(error)}

Error message

subagent: ${name} listener threw: ${renderThrown(error)}

What it means

Error "subagent: ${name} listener threw: ${renderThrown(error)}" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/subagent/subagent/src/lifecycle.ts:119

  ctx: Context,
  carrier: (parent: Agent) => object,
): LifecycleEmitter {
  return (
    name: 'subagent/start' | 'subagent/end' | 'subagent/provider-removed',
    info: SubagentRunInfo | SubagentRunEndInfo | string,
    parent?: Agent,
  ): void => {
    const dispatchArgs: unknown[] = parent === undefined
      ? [name, info]
      : [carrier(parent), name, info]
    for (const callback of ctx.events.dispatch('emit', dispatchArgs)) {
      try {
        const returned: unknown = callback(info)
        void Promise.resolve(returned).catch((error: unknown) => {
          ctx.logger.warn(`subagent: ${name} listener rejected: ${renderThrown(error)}`)
        })
      } catch (error: unknown) {
        ctx.logger.warn(`subagent: ${name} listener threw: ${renderThrown(error)}`)
      }
    }
  }
}

/**
 * Emit the start/end lifecycle pair for one accepted one-shot run.
 * @param emit - the contained lifecycle emitter.
 * @param provider - the provider that established the run.
 * @param parent - the delegating parent keying scoped dispatch.
 * @param run - the published run whose settlement closes the pair.
 * @returns the same run, unchanged.
 */
export function observeRun(
  emit: LifecycleEmitter,
  provider: string,
  parent: Agent,
  run: SubagentRun,

View on GitHub (pinned to b150a551b8)

Solutions

1. Fix the exception in the named subagent lifecycle listener.

When it happens

Trigger: Thrown at packages/subagent/subagent/src/lifecycle.ts:119 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/45b46f32f72c98a5. Report an issue: GitHub.