[BUG] Failed to create bridge sockets after 5 attempts" — every session exits code 1 on Claude Desktop 1.3036.0

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Every agent session in Claude Desktop fails instantly with exit code 1. The error "Failed to create bridge sockets after 5 attempts" appears in cowork_vm_node.log within ~1 second of process spawn. Affects both new and resumed sessions, scheduled tasks, and manually-triggered agents. Claude Desktop is fully non-functional for agent use. Claude.ai in browser works normally.

What Should Happen?

When I trigger an agent in Claude Desktop (either manually or via a scheduled task), the agent should spawn successfully, establish its sandbox bridge sockets, and begin processing the task — returning output as expected.

Instead, the Claude Code process spawns, then dies within ~1 second with "Failed to create bridge sockets after 5 attempts" and exit code 1 before producing any output. No agent can run.

Expected: Agent sessions start, run to completion, and return results.
Actual: Every session exits with code 1 immediately after spawn.

Error Messages/Logs

2026-04-16 14:18:46 [info] [VM:start] Beginning startup, bundlePath=.../vm_bundles/claudevm.bundle
2026-04-16 14:18:46 [info] [VM:start] Bundle version: 5680b11bcdab215cccf07e0c0bd1bd9213b0c25d
2026-04-16 14:18:46 [info] [VM:start] VM instance ID: df123b50-3f2f-41de-9d2e-ca63213f492d
2026-04-16 14:18:49 [info] [VM:steps] download_and_sdk_prepare completed (3184ms)
2026-04-16 14:18:55 [info] [VM] Network status: CONNECTED
2026-04-16 14:18:55 [info] [VM] Guest connection changed: true
2026-04-16 14:18:56 [info] [VM:steps] sdk_install completed (346ms)
2026-04-16 14:18:56 [info] [VM:start] Startup complete, total time: 9704ms
2026-04-16 14:19:06 [info] [VM] API reachability: REACHABLE

2026-04-16 14:22:18 [info] [Spawn:config] Creating spawn function for process=admiring-confident-lamport, 
  isResume=true, mounts=11, allowedDomains=4
2026-04-16 14:22:18 [info] [Spawn:create] cmd=/usr/local/bin/claude args=--output-format stream-json 
  --verbose --input-format stream-json --max-thinking-tokens 31999 --effort medium --model claude-opus-4-6 
  --permission-prompt-tool stdio --resume 56698465-66c8-41fc-99af-b6ea3db6d54c [plus allowed tools list] 
  --setting-sources=user --permission-mode default --allow-dangerously-skip-permissions 
  --include-partial-messages --plugin-dir /sessions/.../.remote-plugins/plugin_01FH9TqiaHWhhAGSQo7UCTZt 
  --plugin-dir /sessions/.../.remote-plugins/plugin_01MKcJsEAmPJswuCytbMJYZJ 
  --plugin-dir /sessions/.../.remote-plugins/plugin_01XH8yMVJbQydrVkX6WgLvck --replay-user-messages
2026-04-16 14:22:18 [info] [Spawn:vm] OAuth token approved with MITM proxy
2026-04-16 14:22:18 [info] [Spawn:vm] Spawn succeeded in 48ms
2026-04-16 14:22:19 [warn] [vm-stderr] Error: Failed to create bridge sockets after 5 attempts
2026-04-16 14:22:19 [info] [Process] Exited, code=1, signal=null, duration=1050ms, oom=false

Steps to Reproduce

1. Open Claude Desktop (v1.3036.0 on macOS Tahoe 26.3.1, M2)
2. Trigger any agent session — manually open an agent, or wait for a scheduled task
3. Observe: session shows "working" briefly, then fails
4. Check ~/Library/Logs/Claude/cowork_vm_node.log
5. See "Failed to create bridge sockets after 5 attempts" followed by "Exited, code=1"

Reproduces 100% of the time across:

• New sessions (isResume=false)
• Resumed sessions (isResume=true)
• Scheduled tasks
• Manual agent launches
• Fresh binary download (cleared ~/Library/Application Support/Claude/claude-code/)
• After full macOS reboot

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Unknown — was working earlier this morning

Claude Code Version

2.1.111

Platform

Other

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

Bug: "Failed to create bridge sockets after 5 attempts" — every agent session exits code 1

Environment

• Claude Desktop version: 1.3036.0
• Claude Code binary (bundled): 2.1.111
• macOS: Tahoe 26.3.1
• Hardware: MacBook Air M2 (2022, Apple Silicon arm64)
• Shell: zsh
• Subscription: [add yours — Pro/Max/Team/Free]

What's broken

Every agent session in Claude Desktop fails instantly with exit code 1, within ~1 second of spawning. Affects BOTH new sessions and resumed sessions, BOTH scheduled tasks and manual agents. No agent can run at all.

Error (from ~/Library/Logs/Claude/cowork_vm_node.log)

[Spawn:vm] OAuth token approved with MITM proxy
[Spawn:vm] Spawn succeeded in 48ms
[vm-stderr] Error: Failed to create bridge sockets after 5 attempts
[Process] Exited, code=1, signal=null, duration=1050ms, oom=false

The VM itself boots cleanly (guest connected, network reachable, SDK installed). The crash happens in the binary's sandbox bridge setup after successful spawn.

Full log excerpt (relevant window)

2026-04-16 14:18:46 [info] [VM:start] Beginning startup, bundle version 5680b11bcdab215cccf07e0c0bd1bd9213b0c25d
2026-04-16 14:18:56 [info] [VM:start] Startup complete, total time: 9704ms
2026-04-16 14:19:06 [info] [VM] API reachability: REACHABLE
2026-04-16 14:22:18 [info] [Spawn:config] Creating spawn function for process=admiring-confident-lamport, isResume=true, mounts=11, allowedDomains=4
2026-04-16 14:22:18 [info] [Spawn:vm] OAuth token approved with MITM proxy
2026-04-16 14:22:18 [info] [Spawn:vm] Spawn succeeded in 48ms
2026-04-16 14:22:19 [warn] [vm-stderr] Error: Failed to create bridge sockets after 5 attempts
2026-04-16 14:22:19 [info] [Process] Exited, code=1, signal=null, duration=1050ms, oom=false

Troubleshooting already performed (none resolved the issue)

• Cleared ~/Library/Application Support/Claude/claude-code/ — forced fresh binary redownload (same 2.1.111)
• Cleared ~/Library/Application Support/Claude/claude-code-vm/
• Cleared stale /tmp/claude-* folders
• Cleared 13 stale com.anthropic.claudefordesktop.ShipIt.* folders from TMPDIR
• Cleared claude-hostloop-plugins from TMPDIR
• Full macOS reboot
• Verified no ANTHROPIC_API_KEY, ANTHROPIC_BASE_URL, or ANTHROPIC_AUTH_TOKEN env vars set
• Verified no Claude/Anthropic references in .zshrc, .zshenv, .zprofile, .bash_profile, .bashrc
• Verified TMPDIR exists and is writable (/var/folders/lz/.../T/)
• Confirmed local-agent-mode-sessions/ data is intact (213 persisted sessions load correctly)

Related existing issues

• #19503 — Cowork 'Failed to create bridge sockets' error on session resume
• #23746 — Failed to create bridge sockets on every new task after auto-update
• #11079 — Sandbox Error: Failed to create bridge sockets when TMPDIR is non-existent or non-writable (doesn't apply — TMPDIR is fine here)
• #40540 — Desktop App: Claude Code crashes with exit code 1 - SDK flag incompatibility

Impact

Claude Desktop is completely non-functional for agent use on this machine. Cannot run manual agents, scheduled tasks, or resumed sessions. Claude.ai web works fine — this is specific to Desktop's local agent VM.

Additional context

• Plugins installed: 3 remote plugins with MCP servers (slack, notion, asana, linear, atlassian, ms365, canva, figma, and others — all being "shadowed with no-ops to prevent SDK double-load" per logs)
• Fresh binary 2.1.111 after cache clear still exhibits the bug
• Problem persists across full macOS reboot
• socat is NOT installed on the host (but per issue #19503 the bridge sockets are created inside the VM guest, not on the host, so this shouldn't matter)