MCP client for `computer-use` failed to start

[LuisJG8]

What version of Codex CLI is running?

0.130.0

What subscription do you have?

Pro

Which model were you using?

gpt-5.5 xhigh fast

What platform is your computer?

Darwin 24.6.0 arm64 arm

What terminal emulator and version are you using (if applicable)?

Warp 0.2026.05.13.09.15.01

What issue are you seeing?

error message:
⚠ MCP client for computer-use failed to start: MCP startup failed: handshaking
with MCP server failed: connection closed: initialize response

⚠ MCP startup incomplete (failed: computer-use)

I only see the error message when I open a new Codex session.

What steps can reproduce the bug?

Uploaded thread: 019e2c3a-4797-7ff2-9e4c-bb78c1d13919

What is the expected behavior?

I should not be able to see the error since I have computer-use enabled. I can also use the computer-use plugin and skill even though I have that visual error on the CLI.

Additional information

I think this might just be a visual bug on the terminal. I don't think this is because I am using Warp. I also tried macOS terminal and I see the same visual error.

[RussellBrand]

I am seeing the same visible MCP startup error on macOS 15, but the underlying failure is a Swift runtime symbol mismatch before the MCP server can respond to initialize.

Environment:

Codex CLI: codex-cli 0.130.0
macOS: 15.7.3
Build: 24G419
Architecture: arm64
Plugin: computer-use@openai-bundled
Plugin version path: ~/.codex/plugins/cache/openai-bundled/computer-use/1.0.791
Helper binary: Codex Computer Use.app/Contents/SharedSupport/SkyComputerUseClient.app/Contents/MacOS/SkyComputerUseClient

Visible Codex error:

MCP client for `computer-use` failed to start: MCP startup failed: handshaking
  with MCP server failed: connection closed: initialize response

Underlying log from ~/.codex/log/codex-tui.log:

dyld: Symbol not found: _swift_task_addPriorityEscalationHandler
  Referenced from: .../SkyComputerUseClient
  Expected in: /usr/lib/swift/libswift_Concurrency.dylib

Direct repro:

cd ~/.codex/plugins/cache/openai-bundled/computer-use/1.0.791
./Codex\ Computer\ Use.app/Contents/SharedSupport/SkyComputerUseClient.app/Contents/MacOS/SkyComputerUseClient mcp

Observed result:

dyld: Symbol not found: _swift_task_addPriorityEscalationHandler
  Referenced from: .../SkyComputerUseClient
  Expected in: /usr/lib/swift/libswift_Concurrency.dylib

Additional evidence from the bundled app metadata:

LSMinimumSystemVersion: 15.0
DTSDKName: macosx26.4
DTPlatformVersion: 26.4
DTXcodeBuild: 17E202

So this does not appear to be a Codex reinstall/cache issue. The helper process exits before MCP initialization because it is calling a Swift concurrency symbol that is not present in the macOS 15.7.3 system Swift runtime at /usr/lib/swift/libswift_Concurrency.dylib.

Expected behavior:

• publish a computer-use build that is actually compatible with macOS 15 if LSMinimumSystemVersion = 15.0 is intended, or
• update the plugin/system requirement and have Codex report a clear OS/runtime compatibility error instead of the generic MCP handshake failure.

Current workaround is disabling the plugin:

[plugins."computer-use@openai-bundled"]
enabled = false