Normalize connection logging

[cliffhall]

DON'T MERGE UNTIL #470 IS MERGED

• In server/index.js

  • in createTransport()
    • stringify query params to put them on one line
    • remove logging of transport creation (done in callers)
  • in /mcp POST handler
    • report POST request if session id is present
    • otherwise, report new StreamableHttp connection request
    • report creation of server transport
    • report creation of client transport
  • in /stdio GET handler
    • report new STDIO connection request
    • report creation of server transport
    • report creation of client transport
    • report 401 as authentication error without stack
    • in stderr data handler
      • if it includes "MODULE_NOT_FOUND"
        • report "Command not found"
        • remove transports
      • otherwise send to client as usual
  • in /sse GET handler
    • report SSE connection request
    • report 401 as authentication error without stack
    • report 404 as server that may not support SSE
    • report error with "ECONNREFUSED" as "Connection refused" without stack
    • only create, map, and proxy transports if serverTransport was successfully created
  • in /message POST handler
    • report received POST message

• In mcpProxy.ts

  • in onServerError()
    • if error message includes 404 OR error.cause includes ECONNREFUSED, report "Connection refused."

Motivation and Context

Normalize the reporting of connection success and errors. The logging is verbose and different for every server type. This is an attempt to make the console output cleaner and more readable.

How Has This Been Tested?

Connection attempts when server is present or absent. Before and after for each server type follows

SSE Connections

Existing SSE connection success

New SSE connection success

Existing SSE connection fail (no server at address)

New SSE connection fail (no server at address)

Existing SSE connection fail (no endpoint on server)

New SSE connection fail (no endpoint on server)

STDIO Connections

Existing STDIO connection success

New STDIO connection success

Existing STDIO connection fail

New STDIO connection fail

StreamableHttp Connections

Existing StreamableHttp connection success

New StreamableHttp connection success

Existing StreamableHttp connection fail

New StreamableHttp connection fail

Breaking Changes

Nope.

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] Documentation update
• [x] Output formatting

Checklist

• [x] I have read the MCP Documentation
• [x] My code follows the repository's style guidelines
• [x] New and existing tests pass locally
• [x] I have added appropriate error handling
• [ ] I have added or updated documentation as needed

Additional context

This fixes #348