Record & Replay fails to initialize after Codex update to 26.908.40834 (build 8881) on macOS

ChatGPT Bugs
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After updating Codex on macOS this morning, Record & Replay stopped loading its recording tools.

Versions

  • Codex: 26.908.40834, build 8881
  • Previous Codex build: 8378
  • Record & Replay plugin: 1.0.1000968
  • Computer Use component: 26.902.1000968, build 1000968

Expected behavior

The plugin initializes and exposes event_stream_start, event_stream_status, and event_stream_stop.

Actual behavior

The skill instructions load, but the recording tools are unavailable. The event-stream MCP server fails during initialization:

MCP startup failed: handshaking with MCP server failed:
JSON-RPC error: -32603: Internal error:
The data couldn’t be read because it isn’t in the correct format.

Timeline — September 14, 2026, UTC+8

  • 08:57:05 — The recording service successfully initialized in the previous Codex process.
  • 08:57:45 — The update download completed.
  • 08:58:20 — The updated Codex process started.
  • 08:59:33 — The first local event-stream initialization failure appeared.

My most recent confirmed successful recording was on September 10.

Troubleshooting performed

  • Uninstalled and reinstalled Record & Replay.
  • Fully quit and relaunched Codex.
  • Confirmed the plugin is enabled and its executable exists.
  • Verified that native Computer Use and Chrome page reading can work while Record & Replay remains unavailable.

Additional diagnostic finding

An isolated initialization test against the bundled recording MCP executable showed:

  • capabilities: {} → succeeds.
  • capabilities: {"experimental": {}} → succeeds.
  • capabilities: {"experimental": {"test": {}}} → reproduces the same -32603 error.

With the minimal initialization request, tools/list successfully returns all three recording tools.

This suggests an initialization compatibility issue. However, I have not captured the actual initialization request sent by the desktop app, so the specific cause remains unconfirmed.

Could the team check whether build 8881 changed the MCP initialization payload in a way that is incompatible with the bundled Record & Replay component? Is there a supported fix or rollback option?