Codex Desktop regression: Subagents panel no longer opens a writable child-agent chat

[parthi2929]

What version of the Codex App are you using?

• Codex Desktop on Windows
• App package: OpenAI.Codex 26.715.8383.0
• Bundled runtime: codex-cli 0.145.0-alpha.27

What subscription do you have?

ChatGPT paid account.

What platform is your computer?

Windows x64.

What issue are you seeing?

The Subagents panel shows Active and Done child agents. I cannot open a child agent as an interactive chat or send it a direct follow-up.

This workflow worked in an earlier Codex Desktop build. I could open the subagent thread and continue talking with that agent while it retained its delegated context.

Current behavior:

• An active child remains shown as “thinking”.
• Completed children appear under Done.
• Selecting the child fails to provide a writable child conversation.
• Starting another child only produces another Active/Done entry with the same limitation.
• The parent can relay a message through collaboration tools, which adds an extra parent turn and removes the direct user-to-child workflow.

This affects long test reviews where a specialist subagent holds the complete review context and the user needs to question that same agent directly.

What steps can reproduce the issue?

1. Open a task in Codex Desktop.
2. Ask the parent agent to create a subagent for a long-running review.
3. Open the Subagents panel.
4. Select the active child entry and try to open its chat.
5. Try to send the child a direct question.
6. Repeat after the child completes and appears under Done.

What is the expected behavior?

Selecting an active or completed subagent should open its child thread.

• An active child should accept direct steering.
• An idle or completed child should accept a follow-up turn.
• The child transcript and delegated context should remain available.
• The parent task should remain the default task when the user returns to it.

Additional information

This appears related to the MultiAgentV2 direct-input policy:

• MultiAgentV2: Allow child threads to accept corrections and steering #33885
• app-server: reject direct input to multi-agent v2 sub-agents #27173
• Make parent-owned sub-agent threads read-only in the TUI #33841

Issue #33885 documents the app-server error direct app-server input is not allowed for multi-agent v2 sub-agents and the read-only child-thread policy. This report covers the Codex Desktop experience: the Subagents panel still presents child entries while the previous direct-chat workflow is unavailable.

Known-good legacy comparison

Local rollout metadata confirms the earlier writable workflow:

• A Codex Desktop task created on 2nd Jul 2026 used codex-cli 0.142.5 with multi_agent_version: v1.
• Retained Desktop logs map Windows package OpenAI.Codex 26.623.19656.0 directly to bundled codex-cli 0.142.5.
• A fresh user-owned root task created on 8th Jul 2026 under that package resolved to multi_agent_version: v1; its spawned children also resolved to V1.
• Its children were stored as durable thread_source: subagent / thread_spawn threads with parent IDs and agent roles.
• A child rollout contains a direct user_message event and the child agent's reply, confirming direct user-to-child chat.
• A resumed legacy V1 parent still spawned V1 children under codex-cli 0.145.0-alpha.18 on 20th Jul 2026.
• Newly created tasks in the current Desktop build use MultiAgentV2 and appear in the read-only Active/Done panel.

This identifies the V1-to-V2 workflow change as the compatibility boundary.

Verified release boundary

• PR app-server: reject direct input to multi-agent v2 sub-agents #27173 explicitly limits the direct-input rejection to MultiAgentV2 and leaves V1 agents writable.
• Merge commit 1026e9de1be292ebb01579dfcce5a34ab224917a is absent from stable 0.139.0.
• The commit first appears in 0.140.0-alpha.2 and is included in stable 0.140.0.
• Stable 0.139.0 is therefore the strongest verified CLI rollback target for removing the app-server rejection itself.
• PR Make parent-owned sub-agent threads read-only in the TUI #33841 later added the read-only capability and UI layer. It first appears in 0.145.0-alpha.22 and is included in stable 0.145.0.

The locally observed Desktop package 26.715.7063.0 bundled 0.145.0-alpha.18. That build predates the later read-only UI layer and still contains the earlier MultiAgentV2 app-server rejection.

The current Desktop frontend accepts the CODEX_CLI_PATH environment override. Its packaged application code also declares 0.141.0 as the minimum supported app-server version and rejects older runtimes with codex-app-server-version-unsupported. This prevents current Desktop package 26.715.8383.0 from using the fully pre-rejection CLI target 0.139.0 as a simple override.

Public issues #28094 and #28348 map the About build 26.609.41114 to Windows package OpenAI.Codex 26.609.4994.0 with CLI 0.139.0. This is the strongest public mapping for a fully pre-#27173 Desktop stack. Public issue #27175 also reports Desktop 26.602.71036 with CLI 0.138.0 and stability problems in that package. An official historical MSIX download is currently unavailable through the published stable installer URL or Microsoft Store version listing.

The strongest locally verified Desktop rollback target for restoring the former writable-child workflow is therefore OpenAI.Codex 26.623.19656.0. A signed historical installer for this exact package remains required.

[github-actions]

Potential duplicates detected. Please review them and close your issue if it is a duplicate.

• MultiAgentV2: Allow child threads to accept corrections and steering #33885
• Allow direct conversation with a subagent thread without interrupting the parent thread #34377

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[Alien-AV]

Still present, extremely disruptive. This breaks the workflow where subagents are dispatched by a single long-running main thread and the user iterates with some of the subagents directly, not wasting main-thread context (and time!).