Claude Desktop 1.1.3963: SSE/URL MCP server crashes app on launch (TypeError in _splat logger)

Description

Claude Desktop v1.1.3963 (Windows) crashes on launch when an MCP server using URL/SSE transport is configured in claude_desktop_config.json. The same configuration worked without issues on v1.1.3918.

Steps to Reproduce

1. Install Claude Desktop v1.1.3963 on Windows
2. Add an MCP server using URL transport to claude_desktop_config.json:

{
  "mcpServers": {
    "pieces-ltm": {
      "url": "http://localhost:39300/model_context_protocol/2025-03-26/mcp"
    }
  }
}

1. Launch Claude Desktop → immediate crash dialog: "Claude Desktop failed to Launch"

Expected Behavior

App should launch and connect to the SSE MCP server (or gracefully handle connection failure).

Actual Behavior

App crashes before rendering any UI. The error in launch-failure.err:

TypeError: Cannot read properties of undefined (reading 'value')
    at formatProperty (node:internal/util/inspect:2280:12)
    at formatRaw (node:internal/util/inspect:1176:9)
    at formatValue (node:internal/util/inspect:932:10)
    at formatProperty (node:internal/util/inspect:2283:11)
    at formatRaw (node:internal/util/inspect:1176:9)
    at formatValue (node:internal/util/inspect:932:10)
    at inspect (node:internal/util/inspect:409:10)
    at formatWithOptionsInternal (node:internal/util/inspect:2582:25)
    at Object.format (node:internal/util/inspect:2502:10)
    at i._splat (app.asar\.vite\build\index.js:65:5632)

Isolation

• Empty mcpServers: {}: launches fine
• Only pieces-ltm (URL/SSE): crashes
• 4 other MCP servers (all stdio transport): all work fine (github/npx, windows-mcp/npx, context7/npx, criminal-defense/python)
• v1.1.3918 with same config: worked fine before auto-update

Analysis

The crash is in Node.js util.inspect → formatProperty trying to access .value on an undefined property descriptor. This happens inside the Winston logger's _splat formatter. It appears the SSE/URL MCP connection (or its error) produces an object with a property that has a getter/proxy/accessor that util.inspect cannot serialize, and the logger crashes trying to format it.

This is a regression from v1.1.3918 → v1.1.3963.

Environment

• OS: Windows 11 Pro 10.0.26220
• App version: 1.1.3963 (commit 71a7aee7e4c1ab9eb313dc3051d72cf09be28d70)
• Previous working version: 1.1.3918
• Node: 24.13.0 (bundled)
• MCP server: PiecesOS LTM (localhost:39300, SSE transport)
• CPU: i9-11900K
• RAM: 48GB