Windows Desktop does not surface a healthy WSL stdio MCP server

Windows Desktop does not surface a healthy WSL stdio MCP server

Summary

On Windows, Codex Desktop did not expose the tools of a healthy stdio MCP
server launched through wsl.exe, although the same configuration was enabled
in codex mcp list and the exact server command completed a full MCP protocol
probe. This resembles the existing WSL spawn-bridge reports, but the server in
this reproduction is Docker-backed and does not require Node or Python on the
Windows host.

Environment

• Codex Desktop Windows: 26.715.3651.0
• Codex CLI: 0.144.1
• WSL distribution: Ubuntu 24.04
• Docker Desktop engine: 29.6.1
• MemPalace container: 3.5.0

Sanitized configuration

[mcp_servers.mempalace]
command = "wsl.exe"
args = ["-d", "Ubuntu-24.04", "--", "docker", "run", "-i", "--rm",
        "-v", "theseus-mempalace-clean:/data", "theseus-mempalace:pilot"]
enabled = true
startup_timeout_sec = 60
tool_timeout_sec = 120

Evidence

1. codex mcp get mempalace reported the server as enabled using stdio.
2. Running the exact launcher independently completed MCP initialize, then

notifications/initialized, then tools/list.

1. The response identified MemPalace 3.5.0 and returned 36 tools.
2. In the running Desktop task, no mempalace_* tools were surfaced, while

other configured MCP tools were available.

1. A bounded Windows process/network snapshot found Codex Desktop, its

code-mode host, Docker Desktop, and expected local service listeners alive;
it did not indicate a Docker or WSL outage.

Candidate workaround

The same container and volume pass the identical full MCP probe when launched
with native docker.exe instead of wsl.exe:

[mcp_servers.mempalace]
command = "docker.exe"
args = ["run", "-i", "--rm", "-v", "theseus-mempalace-clean:/data",
        "theseus-mempalace:pilot"]

This removes only the Desktop-to-WSL process hop. It preserves the volume and
MCP server. Desktop reload verification is still pending after a full restart,
so this is a candidate workaround rather than a confirmed product fix.

Expected behavior

When codex mcp list reports an enabled stdio server and the exact command
successfully completes initialize and tools/list, Codex Desktop should
surface the server tools or provide a visible startup error with captured
stderr.

Related reports

• #21147: Windows Desktop WSL mode launches a Windows app-server path.
• Discussion #5471: MCP servers work from WSL CLI but are not detected in the

Windows IDE/WSL bridge.