add npm run dev:sdk to get live sdk changes w/ simple server

[ochafik]

Introduces an npm run dev:sdk script that allows live edit/rebuild of the SDK + inspector codebases.

TL;DR: npm run dev:sdk "cd sdk && npm run examples:simple-server:w" and open http://localhost:3000/mcp as SHTTP

Motivation and Context

The inspector is great to test SDK changes, but there's a bit of gymastics required: there's no watch-enabled build of the SDK, and no instructions or scripts to npm link.

How Has This Been Tested?

This builds upon modelcontextprotocol/typescript-sdk#663

• Checkout this Inspector branch & the SDK:

  git clone https://github.com/modelcontextprotocol/typescript-sdk
  git clone https://github.com/modelcontextprotocol/inspector
  cd inspector
  git checkout ochafik/dx-inspector-sdk

• If the sdk isn't in ../typescript-sdk, set MCP_SDK env

• Run the simpleStreamableHttp.ts example server alongside the inspector & SDK:

  npm run dev:sdk "cd sdk && npm run examples:simple-server:w"

• Open http://localhost:3000/mcp as Streamable HTTP in the inspector

• Inspector & SDK edits should be reflected ~live

To undo the linking of the local typescript-sdk codebase, run npm run unlink:sdk && npm i.

Breaking Changes

None

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

Checklist

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