Computer Use helper SIGTRAPs on every click after get_app_state succeeds

What happened?

Computer Use can inspect an application successfully, but the first UI action immediately crashes SkyComputerUseService.

get_app_state returns a normal screenshot and accessibility text. A subsequent coordinate click against the same application fails with:

Sky Computer Use native pipe closed before response

A fresh SkyComputerUseService-*.ips crash report is written for each failed action. This reproduces in Citrix Viewer and in a simple local application such as Calculator, so it is not specific to the target application.

Environment

• Codex desktop app: 26.825.32147 (build 7303)
• Computer Use plugin: 1.0.1000901
• SkyComputerUseService: 26.826.1000901 (build 1000901)
• macOS: 26.6.1 (25G76)
• Architecture: Apple Silicon (arm64)

Crash signature

exception: EXC_BREAKPOINT
signal: SIGTRAP
termination: Trace/BPT trap: 5
faulting thread: Window Bounds Observer
top frame: _dispatch_assert_queue_fail
next frames: dispatch_assert_queue$V2.cold.1, dispatch_assert_queue,
             _swift_task_checkIsolatedSwift

The failure appears to be an internal Swift executor/dispatch-queue assertion in the window-bounds observer. The inspected application remains alive; only the Computer Use helper exits and restarts.

Steps to reproduce

1. Open any ordinary macOS application (reproduced with both Citrix Viewer and Calculator).
2. Call get_app_state; observe that it returns a valid screenshot and accessibility text.
3. Call click using valid coordinates within the visible application window.
4. Observe Sky Computer Use native pipe closed before response.
5. Confirm that a new SkyComputerUseService-*.ips report was created with the signature above.

Troubleshooting already attempted

• Fully quit and relaunched the Codex desktop app.
• Restarted Citrix Viewer and the remote session.
• Repeated the test against Calculator to exclude Citrix/Epic as the cause.
• Disabled Mac Mouse Fix and its launch helper, then retested.

The failure persisted unchanged.

Expected behavior

The click should be delivered and SkyComputerUseService should remain alive.

Impact

All Computer Use actions are blocked even though state inspection still works. This breaks an established, time-sensitive Citrix workflow that previously worked reliably.

Related reports

• #34432 also reports SkyComputerUseService SIGTRAP, but that report crashes during accessibility-tree inspection. In this case, inspection succeeds consistently and the crash occurs on the first action.

The full .ips file is intentionally omitted because it contains local identifiers and paths. A sanitized or privately shared crash report can be provided if requested.

Start by reproducing the get_app_state then click sequence against Calculator, and inspect the SkyComputerUseService crash report for the Window Bounds Observer and Swift executor assertion. Done means a coordinate click succeeds and SkyComputerUseService remains alive without the native pipe closing.