[Windows Desktop] create_thread absent from tool manifest in a task that instructs agents to use it

Codex version

• Codex CLI: 0.155.0-alpha.2.6
• Codex Desktop build: not exposed by the local executable metadata
• Platform: Microsoft Windows NT 10.0.26200.0 (64-bit)

What issue are you seeing?

In a Codex Desktop task, the app-provided instructions explicitly told the agent to use create_thread when the user asks to create a new task. The user then explicitly asked:

create a new chat/task to explore https://github.com/jarrodwatts/jev-trader

However, create_thread was absent from the task's callable tool manifest. Searches of the available tools by exact name and by thread/task-management descriptions returned no task-management tools, so the agent could not create the requested task.

This was not an approval rejection or a failed tool invocation: the capability was not exposed at all.

Steps to reproduce

1. Open a projectless task in Codex Desktop on Windows.
2. Ask the agent to create a new chat/task for a repository exploration.
3. Have the agent inspect its available tools.
4. Observe that create_thread (and the related thread-management tools) may be absent even though the app-injected instructions say to use them for this request.

Expected behavior

When the app instructs an agent to use create_thread, the tool should be present and callable for an explicit user request. If the feature is unavailable for the current account, task type, or runtime, the app should avoid injecting contradictory instructions and should expose a clear diagnostic reason.

Actual behavior

The agent had to decline the requested task creation because no create_thread tool existed in the session manifest.

Additional information

• No repository operation was attempted.
• No secrets, user identifiers, private conversation text, local paths, or raw logs are included.
• Restart/update guidance was suggested, but the session itself exposes no diagnostic explaining why the tool was omitted.

Start by reproducing a projectless Codex Desktop task on Windows and inspect the callable tool manifest alongside the app-injected instructions. Done means an explicit request to create a task either exposes create_thread and allows it to run, or the instructions are omitted with a clear diagnostic explaining why the feature is unavailable.