[Bug] MCP connectors timeout at 30s despite fast endpoint response; claude.ai-scoped connectors fail while functioning in Claude app

Bug Description
▎ Claude Code CLI cannot connect to two custom claude.ai-scoped MCP connectors (meta-ads, SyncHub). claude mcp list reports "connection timed out after 30000ms" for both. The same connectors pull live data normally in the Claude app on the same account and machine. The endpoints answer a direct POST in 0.3s. Raising MCP_TIMEOUT to 120000 fails identically at 120s, so it hangs rather than being slow. Every other connector in the session works. Secondary issue: inside a session this surfaces only as "still connecting" with zero tools and no error — the timeout is visible only by running claude mcp list separately.

Environment Info

• Platform: darwin
• Terminal: vscode
• Version: 2.1.231
• Feedback ID: 92470abe-42d8-42a9-956a-be4c0b4c2210

Errors

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