[BUG] Regression in 1.15962.2 / SDK 2.1.197 — Bash tool dispatch never reaches the VM (Exit code 1, no output)

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?

Environment: Claude Desktop (Cowork), Windows 11, app build 1.15962.2.0, claude-code-vm SDK 2.1.197. Previously working build: 1.15962.1.0 / SDK 2.1.187.

Summary: After the app auto-updated to 1.15962.2 (SDK 2.1.197) at ~20:03, every Bash tool call returns Exit code 1 with no output — including trivial commands (echo ok, :). The command never reaches the VM. Reproduces in a brand-new clean chat, so it is not a stuck session.

Steps to reproduce:

Open a new chat in Claude Desktop on build 1.15962.2 / SDK 2.1.197.
Run echo ok via the Bash tool.
Result: Exit code 1, empty output.
Expected: ok with exit 0.

Evidence (cross-checked in logs):

main.log: last [workspaceMcpServer] bash: dispatch is from the morning on SDK 2.1.187 (exit=0). Zero dispatch lines after the update.
cowork_vm_node.log: last [vmOneShot] Running: bash is also from the morning. Zero after the update.
The VM itself is healthy on the new build: [VM:start] ... Claude_1.15962.2.0, Installing SDK ... version=2.1.197, API reachability: REACHABLE, Startup complete, and later [startVM] VM already connected.
Conclusion: the Bash command dies in the host MCP tool routing/dispatch layer — above workspaceMcpServer/vmOneShot — before reaching the VM. The VM and a standalone host Git Bash both work fine.
Impact: All Bash/Python-dependent workflows are blocked inside the Desktop app. Workaround = running the claude CLI from Git Bash.

Suspected cause: Bash dispatch regression introduced in app 1.15962.2 / SDK 2.1.197 (2.1.187 worked the same morning).

What Should Happen?

All Bash/Python-dependent workflows are blocked inside the Desktop app. Workaround = running the claude CLI from Git Bash.

Error Messages/Logs

Steps to Reproduce

Open a new chat in Claude Desktop on build 1.15962.2 / SDK 2.1.197.
Run echo ok via the Bash tool.
Result: Exit code 1, empty output.
Expected: ok with exit 0.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

v2.1.152

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

_No response_