deepseek-ai/deepseek-harness · error · ApiRemoteSubagentSessionOwnership

agent-busy

agent-busy

Error message

session "${sessionId}" is a subagent session; use subagent delivery

What it means

Error "session "${sessionId}" is a subagent session; use subagent delivery" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/host/apiproxy/src/api-proxy.ts:1639

        // Another Host entry path may have published the same identity while
        // this operation crossed an asynchronous persistence/filesystem step.
        const live = ctx.agents.get(sessionId)
        if (live !== undefined) {
          if (hasSubagentOwner(live.session, live)) throw new SubagentSessionOwnership(sessionId)
          return live
        }
        const attached = ctx.sessions.get(sessionId)
        if (attached !== undefined && hasSubagentOwner(attached, undefined)) {
          throw new SubagentSessionOwnership(sessionId)
        }
        throw error
      }).finally(() => {
        sessionCreations.delete(sessionId)
      })
      sessionCreations.set(sessionId, creation)
    }
    const agent = await creation
    if (hasSubagentOwner(agent.session, agent)) throw new SubagentSessionOwnership(sessionId)
    // Beside the cwd check for the same reason, and after the await so it
    // covers every path that yields a live agent — freshly created, adopted
    // live, resumed from disk, or recovered by the concurrent-creation catch.
    assertPresetUnchanged(sessionId, presetId, resolveSessionPreset(agent.session))
    if (agent.session.header.cwd !== cwd) {
      throw new SessionCwdConflict(sessionId, cwd, agent.session.header.cwd)
    }
    return agent
  }

  /** Resolve or create one path while holding the Host's workspace-create chain. */
  function ensureWorkspace(path: string): Promise<{ workspace: Workspace; created: boolean }> {
    const operation = workspaceCreationChain.then(async () => {
      const existing = await ctx.workspaceRegistry.resolveByPath(path)
      if (existing !== undefined) return { workspace: existing, created: false }
      return { workspace: await ctx.workspaceRegistry.create(path), created: true }
    })
    workspaceCreationChain = operation.then(() => undefined, () => undefined)

View on GitHub (pinned to b150a551b8)

When it happens

Trigger: Thrown at packages/host/apiproxy/src/api-proxy.ts:1639 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/efce7f7cee48117f. Report an issue: GitHub.