deepseek-ai/deepseek-harness · error

acp: session/update failed: ${String(error)}

Error message

acp: session/update failed: ${String(error)}

What it means

Error "acp: session/update failed: ${String(error)}" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/acp/acp/src/index.ts:153

  }

  const assertOpen = (): void => {
    if (closed) throw internalError('the ACP bridge has been disposed')
  }

  const requireSession = (sessionId: SessionId): SessionRecord => {
    const record = sessions.get(sessionId)
    if (record === undefined) throw invalidParams(`unknown session: ${sessionId}`)
    return record
  }

  /** Send one ordered protocol update while containing transport-only failure. */
  const notify = async (notification: SessionNotification): Promise<void> => {
    try {
      await conn.sessionUpdate(notification)
    /* v8 ignore start -- the ACP SDK contains notification-handler failures; only a transport write failure reaches this guard. */
    } catch (error: unknown) {
      logger.warn(`acp: session/update failed: ${String(error)}`)
    }
    /* v8 ignore stop */
  }

  const rejectFromError = (
    inflight: NonNullable<SessionRecord['inflight']>,
    reason: Extract<TurnEndReason, { kind: 'error' }>,
  ): void => {
    inflight.reject(internalError(`turn failed: ${reason.error.message}`))
  }

  /**
   * Settle one exact prompt only after admission, agent activity, and ordered
   * assistant delivery have all reached quiescence.
   */
  const settleAfterQuiescence = (
    record: SessionRecord,
    inflight: NonNullable<SessionRecord['inflight']>,

View on GitHub (pinned to b150a551b8)

Solutions

1. Inspect the embedded error from session/update and fix the cause (session state, payload); then retry.

When it happens

Trigger: Thrown at packages/acp/acp/src/index.ts:153 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/0fe375bfd43dc614. Report an issue: GitHub.