[BUG] MCP rich UI previews (e.g. Asana task preview) only render in the chat tab, not in the code/editor tab

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?

When using an MCP tool that returns a rich UI preview (e.g. Asana's create_task_preview), the preview renders correctly in the chat tab but is not visible in the code tab — only the raw tool result text is shown.

What Should Happen?

MCP tool rich UI previews (e.g. Asana's task preview card) should render consistently across all tabs — both the chat tab and the code/editor tab should display the same interactive preview component.

Error Messages/Logs

Steps to Reproduce

1. Connect an MCP server that returns rich UI previews (e.g. Asana MCP via Claude's MCP integrations)
2. Open Claude Code and switch to the code/editor tab
3. Ask Claude to create a task preview, e.g. "Create an Asana task called 'Test task'"
4. Claude calls the create_task_preview MCP tool
5. The tool response shows plain text (e.g. "Task preview generated: 'Test task'") — no interactive preview card is rendered

Note: Switching to the chat tab and repeating the same request renders the full interactive preview card with a "Create task" button correctly.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude 1.1.4498 (24f768) 2026-02-26T19:47:09.000Z

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_