Document PyPI+uvx deployment pattern for Python MCP servers

[bryan-anthropic]

Summary

Add minimal documentation for an alternative Python deployment pattern using PyPI and uvx instead of bundling dependencies.

Motivation

During testing, we verified that Python MCP servers can successfully use PyPI for dynamic dependency resolution via uvx. This pattern is already in production use but was undocumented in the MCPB specification.

Changes

README.md

• Add concise section on PyPI-based deployment
• Include trade-offs comparison table
• Link to example implementation

MANIFEST.md

• Add uvx configuration example alongside traditional Python example

examples/pypi-python/

• Complete minimal working example
• Demonstrates manifest and pyproject.toml configuration
• Shows required [project.scripts] entry point setup

Pattern Overview

Manifest configuration:

{
  "mcp_config": {
    "command": "uvx",
    "args": ["--native-tls", "package-name@latest"]
  }
}

Benefits:

• Smaller bundle sizes (< 1 MB vs 50+ MB)
• Automatic updates via @latest tag
• Modern Python packaging alignment

Trade-offs:

• Requires users to install uv tool
• Needs internet connection at first launch

Testing

• ✅ Verified working with test implementation
• ✅ Confirmed PyPI package can be fetched via uvx
• ✅ Validated manifest schema compliance

Documentation Approach

This PR intentionally keeps documentation minimal and generic:

• No company-specific references in core docs
• Concise explanations focusing on essentials
• Working example for reference