deepseek-ai/deepseek-harness · error

sessions.select: unknown session ${sessionId}

Error message

sessions.select: unknown session ${sessionId}

What it means

Error "sessions.select: unknown session ${sessionId}" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/client/runtime/src/client/sessions/manager.ts:188

    restoredSelection?: SessionId,
    restoredAddress?: SubagentAddress,
    private readonly conversation?: ConversationRuntime,
  ) {
    this.selected = restoredSelection
    if (restoredAddress !== undefined) this.addresses.set(restoredAddress.childSessionId, restoredAddress)
    this.listSnapshotCache = this.buildListSnapshot()
  }

  // ---- Selection ----

  /**
   * Select a listed Session or a retained catalog-addressed child.
   * @param sessionId - listed or catalog-addressed Session id.
   */
  select(sessionId: SessionId): void {
    const address = this.navigationAddress(sessionId)
    if (!this.summaries.some(summary => summary.sessionId === sessionId) && address === undefined) {
      throw new Error(`sessions.select: unknown session ${sessionId}`)
    }
    if (address !== undefined) this.addresses.set(sessionId, address)
    this.sessions.get(sessionId)?.configureSubagent(
      address,
      address === undefined
        ? false
        : this.catalogs.get(address.parentSessionId)?.parentAvailable ?? false,
    )
    this.selected = sessionId
    // Looking at the session consumes its completion reminder (dot clears).
    this.completedNotifications.delete(sessionId)
    void this.refreshSubagents(sessionId)
    this.notifier.notifyNow()
  }

  /**
   * Select a healthy child through its durable direct-parent address.
   * @param address - catalog-derived parent and child ids.

View on GitHub (pinned to b150a551b8)

Solutions

1. Select an existing session id from the sessions list.

When it happens

Trigger: Thrown at packages/client/runtime/src/client/sessions/manager.ts:188 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/7740d518aeac9676. Report an issue: GitHub.