Windows first launch can crash with Bun segmentation fault after install

[bhaskarvora-sun]

Summary

During Windows installation / first launch, ax-code crashed with a Bun native segmentation fault. The user reported that after this crash, running ax-code again worked, so this may be transient, but it is still a bad first-run/install experience and should be tracked.

No screenshot is attached here; details below are transcribed from the visible crash output.

Environment details visible in crash output

• ax-code version: 6.5.2
• Runtime: Bun v1.3.14 (0d9b296a) Windows x64
• OS: Windows v.win11_dt
• CPU features shown: sse42 avx avx2
• Shell: Windows PowerShell
• Working prompt path: PS C:\WINDOWS\system32>
• ax-code binary path shown in args: C:\Users\xmenn\.ax-code\bin\ax-code.exe
• UI state before crash: Dev · No provider selected · Connect a provider

Command / args visible in crash output

The crash output shows ax-code launched roughly as:

C:\Users\xmenn\.ax-code\bin\ax-code.exe --user-agent=ax-code/6.5.2 --use-system-ca ...

The visible argument list also includes a sandbox flag at the end, but the full text is partially obscured in the screenshot.

Crash details visible in output

panic(main thread): Segmentation fault at address 0x2AC4F7B0AA2
Oh no. Bun has crashed. This indicates a bug in Bun, not your code.

The output also showed:

Elapsed: 115655ms | User: 4500ms | Sys: 1187ms
RSS: 0.42GB | Peak: 0.42GB | Commit: 0.68GB | Faults: 179098 | Machine: 0.10TB

Actual result

ax-code crashed during launch with a Bun segmentation fault.

Expected result

ax-code should launch cleanly after installation, or fail with a controlled/actionable error instead of a native runtime crash.

Notes

• The crash banner says this is likely a Bun bug, but ax-code packages/runs on Bun, so users experience it as an ax-code install/first-run failure.
• User reported that a later ax-code run worked after the crash. That suggests a transient first-run or environment-specific failure rather than a permanently broken installation.

Suggested follow-up

• Check whether the Windows packaged launcher can collect enough diagnostics to correlate these crashes.
• Consider documenting a workaround/retry message if this is known upstream Bun behavior.
• If reproducible, file upstream with Bun using the generated crash-report URL from the crash output.

[automatosx]

Leaving open as a tracking issue. This is a native Bun segmentation fault on Windows first launch (panic(main thread): Segmentation fault), reported as transient (a subsequent run worked). It is not reproducible from a single ax-code code path and the crash originates in the Bun runtime itself, so there is no safe code change to make in this repo right now.

Note this CPU reports avx2 (unlike #274, which is a separate AVX2-baseline packaging bug). Suggested next steps remain: capture the Bun crash-report URL from the packaged launcher and file upstream with Bun, and consider a first-run retry/diagnostic message in the Windows launcher. Not bundled into the fix/issue-batch-254-274 branch.