[BUG] Empty/whitespace content block causes permanent API 400 error loop in Dispatch Background Tasks dialog

[https://i.imgur.com/rEqI84h.png](url)

Preflight Checklist

• [ ] 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?

Related to #45217, #23270, #23390, #23440, #26870, #22923, #23005, #59294, #57918, and microsoft/vscode#307807 — same root validation gap, different trigger surfaces. Adding a new trigger surface not covered by the existing reports.

Environment: Claude Desktop app, Cowork mode (Dispatch orchestrator), Windows.

Observed:

Recurring API Error: 400 messages: text content blocks must contain non-whitespace text on scheduled background-task wakes — matches #45217's description closely.
New: attempting to authorize/connect the GitHub MCP connector (Settings → Connectors → GitHub) also fails on this same 400. The connector's GitHub App shows as authorized (user consent granted) but never completes installation on any account — consistent with the auth-flow's own request hitting this same empty/whitespace validation before the install step finishes.
Once triggered, the session is stuck permanently — every subsequent request replays the same bad content block from history and fails identically (matches the persisted-history mechanism described in vscode#307807). Only recovery found: abandon/restart the session.

Why it matters beyond chat UX: this currently blocks a real dispatch access to local system resources (can only function within linux) with no user-facing workaround, since the failure is inside Anthropic's own auth/install flow, not anything the session controls.

Suggested fix (matches other threads on this bug): sanitize message content client-side before transmission instead of sending empty parts as-is:

Sources:

microsoft/vscode#307807
anthropics/claude-code#45217
anthropics/claude-code#23390

What Should Happen?

fix this it has been going on for too long and tends to happen often

Error Messages/Logs

Steps to Reproduce

Mulitple Claude desktop app versions

OS: Windows
App: Claude Desktop, Cowork mode (Dispatch orchestrator)
App version: 2.1.219 (pulled from this session's own transcript metadata)

One time happened when sending a simple image without words

Happened a week prior forgot what was sent.

Third time hit clear background tasks

I was able to rename a folder or uuid folder and resolve it but forget which - will update if able to determine which exactly.

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.219

Claude Code Version

2.1.219

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

cant believe how long and how many have had this with autoclose or mod closing issues no resolutions.