[BUG] Blender MCP Install Bug

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?

Summary

The extension-install confirmation dialog for a .mcpb bundle renders its install control as a blank/unlabeled pill button with no visible "Install" text. Clicking it has no effect — the extension is never actually installed.

App version

Claude 1.21459.0 (f7518f), built 2026-07-14T05:32:17.000Z (macOS)

Steps to reproduce

1. Download the Blender MCP extension bundle (blender-1.0.0.mcpb, ~5.5MB).
2. Open the .mcpb file (e.g. via open blender-1.0.0.mcpb or double-click), which launches Claude Desktop's extension-install dialog.
3. Observe the install control in the top-right of the dialog: it renders as an empty grey pill with no label, instead of a labeled "Install" toggle/button.
4. Click the blank control anyway.

Expected behavior

The control should display a legible "Install" label/toggle, and clicking it should install the extension.

Actual behavior

• The control shows no text at all (see attached screenshot).
• Clicking it produces no visible change and no install occurs.
• Confirmed no install actually happened: ~/Library/Application Support/Claude/extensions-installations.json has no entry for the extension, and no corresponding folder is created under ~/Library/Application Support/Claude/Claude Extensions/.

Troubleshooting already tried (no effect on any of these)

• Clicking the blank control directly.
• Toggling macOS Accessibility → Display settings ("Increase Contrast", "Reduce Transparency"), in both directions.
• Fully quitting and relaunching Claude Desktop (Cmd+Q, not just closing the window), then reopening the .mcpb file for a fresh dialog attempt.
• Checking for app updates (already on latest available version).

All attempts reproduce the identical blank-control state with no install recorded.

Attachments

• Screenshot of the blank install dialog (attached separately).

What Should Happen?

The control should display a legible "Install" label/toggle, and clicking it should install the extension.

Error Messages/Logs

Steps to Reproduce

1. Download the Blender MCP extension bundle (blender-1.0.0.mcpb, ~5.5MB).
2. Open the .mcpb file (e.g. via open blender-1.0.0.mcpb or double-click), which launches Claude Desktop's extension-install dialog.
3. Observe the install control in the top-right of the dialog: it renders as an empty grey pill with no label, instead of a labeled "Install" toggle/button.
4. Click the blank control anyway.

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude 1.21459.0 (f7518f), built 2026-07-14T05:32:17.000Z (macOS)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

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