Mac-only: 'Claude couldn't process that message' crashes on fresh sessions with image/Drive workflows

Claude Code: "Claude couldn't process that message" — Mac only

Environment

• Claude Code version: 2.1.132
• macOS: Darwin 24.3.0
• Affected machine: MacBook
• Unaffected machine: Lenovo (Windows) — same account, same MCP tools connected

Problem

Fresh sessions repeatedly crash with "Claude couldn't process that message" on Mac. The same workflows complete without issue on Windows with identical tool configuration.

Errors observed

1. API Error: 400 messages.204.content.3.text: cache_control cannot be set for empty text blocks
2. API Error: 400 messages.204.content.8.text: cache_control cannot be set for empty text blocks
3. API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"Could not process image"}}

Reproduction

1. Start a fresh session on Mac
2. Use the Google Drive MCP (download_file_content) to pull an image file (PNG, ~1.6MB)
3. Attempt to use the image in a subsequent tool call (e.g., Klaviyo upload_image_from_url)
4. Session crashes — sometimes on the image step, sometimes on the next message after

Multiple fresh sessions hit this on the same workflow. At least 5 separate sessions attempted (see screenshot of session list).

MCP servers connected (same on both machines)

• Google Drive
• Klaviyo
• Shopify
• Gmail
• Facebook Ads
• Canva
• Supabase
• Netlify
• Figma
• Calendar
• PDF Tools
• Claude in Chrome
• Computer Use
• Claude Preview
• Control Chrome
• Control Mac (osascript)
• MCP Registry
• Scheduled Tasks
• Session Management
• + others (23 servers total, 150+ tools)

What's been ruled out

• Not a context length issue — happens on fresh sessions with minimal conversation
• Not a tool count issue — same tools on Windows without issue
• Not a specific session corruption — reproduces across new sessions
• Old session transcripts total ~373MB on Mac but shouldn't affect new sessions

Suspected cause

Platform-specific difference in how MCP servers or Claude Code packages API requests on macOS vs Windows, particularly when image data (base64) is involved in tool results.