[BUG] Stitch generate_screen_from_text never queues via MCP

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?

generate_screen_from_text (Stitch built-in MCP integration on claude.ai) times out on every call and the generation job never reaches Stitch's backend. The tool is completely
non-functional - not just slow.

What Should Happen?

The tool may time out on the Claude side (generation can take 1–2 minutes), but the job should still be queued on Stitch's backend. A subsequent call to list_screens should show the in-progress or completed screen. Instead, list_screens always returns {} after the timeout, confirming the HTTP handoff to Stitch never completed.

Error Messages/Logs

The operation timed out.                                                                                                                                                      
Returned on every call to generate_screen_from_text, regardless of prompt length, model param (GEMINI_3_FLASH or GEMINI_3_1_PRO), or deviceType.

Steps to Reproduce

1. In a claude.ai Claude Code session, call mcp__stitch__create_project with any title — confirm the project is created and note the projectId.
2. Call mcp__stitch__create_design_system and mcp__stitch__update_design_system to attach a design system to the project — both succeed.
3. Call mcp__stitch__generate_screen_from_text with the projectId, a short prompt, and deviceType: "MOBILE". Wait for response.
4. Observe: tool returns The operation timed out.
5. Immediately call mcp__stitch__list_screens with the same projectId.
6. Observe: returns {} — no screen was queued.
7. Repeat step 3 with modelId: "GEMINI_3_FLASH" — same result.

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.98 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

This is specific to the claude.ai built-in Stitch MCP integration (tool prefix mcp__stitch__), not the Claude Code CLI. All other Stitch tools tested in the same session worked correctly: create_project, create_design_system, update_design_system, and list_screens all returned valid responses. The failure is isolated to generate_screen_from_text, suggesting the issue is with how the integration handles long-running HTTP requests specifically — the connection appears to be torn down before Stitch acknowledges the job.