deepseek-ai/deepseek-harness · error · WorkflowError

AGENT_START

AGENT_START

Error message

agent() could not start a child: ${renderThrown(error)}

What it means

Error "agent() could not start a child: ${renderThrown(error)}" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/workflow/workflow-worker-thread/src/runtime.ts:288

      // tick even when a slot is free, and a queued waiter resumes a tick
      // after its release — a cancel() landing in either window must not
      // reach the host (which would refuse anyway, but the refusal reads as
      // a start failure rather than the cancellation it is).
      this.throwIfCancelled()
      let run: ChildHandle
      try {
        run = await this.children.startAgent({
          prompt: rawPrompt,
          ...opts.schema !== undefined ? { schema: opts.schema } : {},
          ...opts.provider !== undefined ? { provider: opts.provider } : {},
          ...opts.model !== undefined ? { model: opts.model } : {},
        })
      } catch (error: unknown) {
        // The host refuses starts once the run is cancelled — a refusal that
        // races our own cancel state must read as the cancellation it is,
        // not as a broken contract.
        if (this.isCancelled()) throw this.cancelledError()
        throw new WorkflowError(`agent() could not start a child: ${renderThrown(error)}`, 'AGENT_START', { cause: error })
      }
      // The start round-trip yields to the event loop, so a cancel CAN land
      // between the host starting the child and this continuation running —
      // wind the fresh child down instead of leaving it live behind a dead
      // script.
      if (this.isCancelled()) {
        await run.dispose()
        throw this.cancelledError()
      }
      const info: WorkflowAgentInfo = { seq, label, ...phase !== undefined ? { phase } : {}, childId: SessionId(run.id) }
      this.observer.agentStart(info)
      try {
        let result
        try {
          result = await run.result
        } catch (error: unknown) {
          // A rejected child result is an INFRASTRUCTURE fault relayed by the
          // host — distinct from a child that failed and resolved. Pair the

View on GitHub (pinned to b150a551b8)

Solutions

1. Read the embedded child-start error (provider missing, budget exhausted) and fix that cause before retrying.

When it happens

Trigger: Thrown at packages/workflow/workflow-worker-thread/src/runtime.ts:288 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/bce3ab2ebf7f015f. Report an issue: GitHub.