Codex VS Code renderer crashes during concurrent agent streaming

Codex
1

I am seeing repeatable full VS Code renderer crashes while the Codex extension is streaming a long-running task with multiple concurrent/background agent threads.

Environment

  • Windows 10.0.26200.8973 (x64)
  • VS Code 1.132.0 (df53daabb18cd157bdb08c7f01c34df936cf12f4)
  • Codex extension 26.803.41515
  • Bundled Codex CLI 0.147.0-alpha.6.5

Crash signature

Three crashes on the same day produced the same minidump signature:

  • EXCEPTION_BREAKPOINT
  • Crashing instruction: int 0x3
  • Crashed thread: CrRendererMain
  • Top frame: Code.exe + 0x2350820

Local symbol analysis maps this offset to Blink’s Document::UpdateStyleAndLayoutTreeForThisDocument() lifecycle check.

Immediately before the latest crash, the Codex log repeatedly contained:

[desktop-notifications][global-error] ResizeObserver loop completed with undelivered notifications.

In the latest session:

  • 308 ResizeObserver loop errors
  • 683 completed reasoning-summary item events
  • During the final ~197 seconds: 7 distinct streaming threads, 77 reasoning-summary events, and 41 ResizeObserver errors

The dump was written at 23:26:47, followed by renderer/extension-host termination at 23:26:49. The extension host received termination from the renderer, so its shutdown errors appear downstream of the renderer failure.

Configuration/workaround result

I set:

model_reasoning_summary = "none"

The turn-start log confirmed:

  • summary=none
  • concurrentReasoningSummariesFeatureOverrideEnabled=false

However, the extension continued receiving hundreds of empty summary events (summary=[], summaryPartCount=0) and the renderer crashed again. This workaround did not prevent the failing UI update path in this environment.

Reproduction

  1. Open the Codex sidebar in VS Code.
  2. Resume a long-running local thread.
  3. Run multiple background/subagent threads concurrently.
  4. Repeated ResizeObserver errors appear.
  5. The VS Code renderer terminates and the window closes; the local session transcript remains recoverable after restart.

Expected

Streaming updates from concurrent Codex threads should not violate Blink layout lifecycle invariants or terminate the VS Code renderer.

Related reports

I can provide sanitized log excerpts or minidump metadata if maintainers need them. I am intentionally not attaching the raw dump publicly because it may contain process memory.

2

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