Claude Desktop Task mode: "Failed to create bridge sockets after 5 attempts" on macOS 26.4

Summary

Task/agent mode in Claude Desktop fails to start any session on macOS 26.4. Every spawn of the in-VM claude CLI exits with code 1 within ~1s. Regular Chat mode works fine; the failure is specific to the agent-mode VM.

Environment

• Claude Desktop: 1.3036.0
• macOS: 26.4 (Darwin 25.4.0, Apple Silicon)
• Claude Code SDK in VM: 2.1.111

Error

From ~/Library/Logs/Claude/cowork_vm_node.log:

[Spawn:vm] Spawn succeeded in 41ms
[vm-stderr] Error: Failed to create bridge sockets after 5 attempts
[Process] Exited, code=1, duration=917ms

Root cause (as far as I can tell)

The VM-side CLI spawns socat TCP-LISTEN:3128 UNIX-CONNECT:/var/run/mitm-proxy.sock (HTTP bridge) and the same for port 1080 (SOCKS). Both fail. The VM itself boots cleanly, network is CONNECTED, and coworkd logs MITM proxy started on /var/run/mitm-proxy.sock, so the socket appears to exist — but the bridge setup fails deterministically.

Likely candidates: race between proxy socket creation and socat connect, permissions on the socket vs. the non-root session user, or a macOS 26.x Virtualization Framework regression.

Reproduction

1. Launch Claude Desktop on macOS 26.4
2. Start a Task mode session
3. Session immediately fails with "error code 1"

What I've tried

• Killed all Claude processes, reinstalled app — no change
• Deleted ~/Library/Application Support/Claude/claude-code-vm, local-agent-mode-sessions, vm_bundles — no change
• Full wipe of ~/Library/Application Support/Claude/ — no change

Chat mode works. claude.ai web works. Only Task mode is affected.