[Bug] Subagent task messages never delivered to spawned agents; agents idle or act on inherited context (Windows desktop app)

What version of the Codex App are you using (From “About Codex” dialog)?

26.818.3698.0 (package: OpenAI.Codex_26.818.3698.0_x64__2p2nqsd0c76g0)【需你确认:请以 About Codex 对话框显示为准,如有差异替换】

What subscription do you have?

其他

What platform is your computer?

Microsoft Windows NT 10.0.26100.0 x64

What issue are you seeing?

Spawned subagents never receive the task text passed via spawn_agent or followup_task. They either complete an onboarding turn and reply "waiting for task", or act only on the context inherited from the parent thread (recursively spawning their own subagents and running unrelated demos). A verbatim quote-back test failed: the agent did not repeat the given message and instead spawned more subagents. Observed in two independent conversations; symptom in the other chat was "subagent invoked but just watching/idle". No error message is shown.

What steps can reproduce the bug?

Feedback ID: 01a025b0-87c5-72a0-ab34-d0e3e2858267

What is the expected behavior?

Per official docs (https://developers.openai.com/codex/subagents), a spawned agent should receive the task text in its own thread and execute it, and its result should return to the parent. Actual behavior: the task text never appears in the agent's visible conversation; agents idle or act on inherited context.

Additional information

• interrupt_agent works reliably; subagents can still spawn recursively (multi-level chains) without ever receiving a task.
• Not config-induced: no [agents] overrides in config.toml.
• Suggested fix area: message delivery into spawned agent threads — both the initial spawn message and follow-up messages (followup_task / queued messages), desktop app build 26.818.3698.0.
• 2026-08-22 retrieved docs at https://developers.openai.com/codex/subagents and https://developers.openai.com/codex/reference/troubleshooting.

Start with the subagent documentation and reproduce the issue using Feedback ID 01a025b0-87c5-72a0-ab34-d0e3e2858267. Trace the spawn_agent and followup_task message-delivery entry points in the Windows desktop app; done means spawned agents receive the task text and return their results to the parent instead of idling or using inherited context.