MCP boolean parameters are serialized as strings, causing validation errors

Description

When calling MCP tools that expect boolean parameters, Claude Code serializes true/false as strings ("true"/"false") instead of JSON booleans. This causes Zod validation errors on the MCP server side.

Steps to Reproduce

1. Connect to Asana's official MCP server (mcp.asana.com/sse) via Claude Code
2. Call asana_update_task with completed: true
3. Observe the error:

MCP error -32602: Input validation error: Invalid arguments for tool asana_update_task: [
  {
    "code": "invalid_type",
    "expected": "boolean",
    "received": "string",
    "path": ["completed"],
    "message": "Expected boolean, received string"
  }
]

Expected Behavior

Boolean parameters should be passed as JSON booleans (true/false), not as strings ("true"/"false").

Actual Behavior

All parameter values are serialized as strings in the XML-like parameter format, so true becomes "true".

Environment

• Claude Code version: 2.1.59 (latest)
• OS: Windows 11
• MCP Server: Asana official (mcp.asana.com/sse)

Notes

• This issue affects any MCP tool that defines boolean parameters, not just Asana.
• Other MCP clients (Roo Code, GitHub Copilot) handle the same Asana MCP server correctly.
• Possibly related to #5504 and #3084 (JSON object serialization issues).