Native cross-task tools absent despite an explicit recipient and send request

• Platform: Windows, Codex desktop package 26.901.6511.0.
• Affected session reports CLI version 0.153.4; an earlier successful session reports 0.153.0. This correlation does not establish a version regression.
• Expected: with an explicit existing recipient task and permission to send, the agent can discover the native task listing/reading/messaging tools, or receives an actionable explanation of why they are unavailable.
• Actual: repeated tool discovery attempts show other codex_app tools but no list_threads, read_thread, send_message_to_thread, or generic tool loader. Specifying the recipient again does not restore them. Agent-tree messaging is available but cannot address the existing desktop task.
• Earlier evidence: an existing session successfully called the native sender and received a non-error response containing the intended destination ID. The successful session's injected app context includes thread-management instructions; the affected session's injected app context does not.
• Read-only inspection of the installed desktop bundle shows tool construction and instruction injection both depend on the thread_tools feature override. The bundle maps feature gate 2395575782 to this override. The effective gate value at the failed turn has not been captured; its absence, a rollout change, and a loading defect have not been distinguished.
• No documented user setting for this desktop gate was located. No application binaries, feature-gate caches, permissions, or session databases were modified.

Please investigate why native thread tools and their instructions are omitted for these desktop turns, whether a supported user control exists, and how existing sessions can refresh the tools after a fix. Please preserve active sessions and avoid requiring users to manually relay messages as the routine workaround.

Validation requested: confirm tool availability in both existing and newly created tasks, then verify an authorized message is accepted and acknowledged by the intended existing task. A successful send in one task alone does not establish availability in all tasks.

Start with the installed desktop bundle's thread_tools feature override, feature gate 2395575782, and the injected app context that controls native thread-tool instructions. Capture and compare the effective gate and tool availability for existing and newly created tasks, then verify an authorized message is accepted and acknowledged by the intended existing task. Done means the cause is identified and sessions can refresh or regain the tools without manual message relaying.