fix: Handle -- separator in command arguments to prevent timeout

[yubingjiaocn]

Summary

Fixes timeout issues when proxying Node.js MCP servers with arguments that start with -.

Close #22

Problem

Commands like npx mcp-proxy --shell npx -- -y @modelcontextprotocol/server-everything were failing with timeout errors because yargs argument parsing didn't properly handle the -- separator.

Solution

• Add preprocessing to detect and handle -- separator in process.argv
• Split arguments into mcp-proxy options (before --) and target command args (after --)
• Preserve backward compatibility for commands without -- separator
• Maintain original behavior where command comes from yargs and everything after -- becomes arguments

Test Results

Both formats now work correctly:

• Without --: npx mcp-proxy --shell npx @modelcontextprotocol/server-everything ✅
• With --: npx mcp-proxy --shell npx -- -y @modelcontextprotocol/server-everything ✅

Tested with @modelcontextprotocol/server-everything - no more timeout errors, successful MCP handshake and server startup.

Backward Compatibility

✅ All existing functionality preserved
✅ All existing tests pass
✅ No breaking changes

🤖 Generated with Claude Code

[punkpeye]

I believe you are looking for https://github.com/yargs/yargs-parser?tab=readme-ov-file#populate---

[yubingjiaocn]

Hi, I updated my implementation with you recommended method. Please review. Thx.

[punkpeye]

Please undo unrelated changes.

[yubingjiaocn]

@punkpeye Reverted.

[punkpeye]

Thank you