Describe the bug

In my typescript ESM module project (https://github.com/compiler-explorer/compiler-explorer) I tried to install and use this package, and it picks up @modelcontextprotocol/sdk@1.11.0. That package appears to come from git+ssh://git@github.com/modelcontextprotocol/typescript-sdk.git#621ccea...
This git package is missing the dist subdirectory.

To Reproduce

1. Create a new project and install dependencies:

mkdir mcp-repro && cd mcp-repro
npm init -y
npm install @modelcontextprotocol/sdk@github:modelcontextprotocol/typescript-sdk tsx

2. Create a simple TypeScript file (mcp-repro.ts):

// Simple file to test MCP SDK import
import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
console.log('McpServer successfully imported:', McpServer);

3. Run the file with tsx: npx tsx mcp-repro.ts

Expected behavior
The script should successfully import the McpServer class from the SDK and output its details.

Actual behavior

$ npx tsx mcp-repro.ts
node:internal/modules/cjs/loader:1281
  const err = new Error(`Cannot find module '${request}'`);
              ^

Error: Cannot find module '/tmp/mcp-repro/node_modules/@modelcontextprotocol/sdk/dist/cjs/server/mcp.js'
    at createEsmNotFoundErr (node:internal/modules/cjs/loader:1281:15)
    at finalizeEsmResolution (node:internal/modules/cjs/loader:1269:15)
    at resolveExports (node:internal/modules/cjs/loader:638:14)
    at Function._findPath (node:internal/modules/cjs/loader:743:31)
    at node:internal/modules/cjs/loader:1230:27
    at nextResolveSimple (/tmp/mcp-repro/node_modules/tsx/dist/register-D2KMMyKp.cjs:3:942)
    at /tmp/mcp-repro/node_modules/tsx/dist/register-D2KMMyKp.cjs:2:2550
    at /tmp/mcp-repro/node_modules/tsx/dist/register-D2KMMyKp.cjs:2:1624
    at resolveTsPaths (/tmp/mcp-repro/node_modules/tsx/dist/register-D2KMMyKp.cjs:3:760)
    at /tmp/mcp-repro/node_modules/tsx/dist/register-D2KMMyKp.cjs:3:1038 {
  code: 'MODULE_NOT_FOUND',
  path: '/tmp/mcp-repro/node_modules/@modelcontextprotocol/sdk/package.json'
}

Node.js v22.13.1

Additional context

Related issues:

1. Issue Error [ERR_PACKAGE_PATH_NOT_EXPORTED] when importing @modelcontextprotocol/sdk #427: Error [ERR_PACKAGE_PATH_NOT_EXPORTED] when importing @modelcontextprotocol/sdk #427
   - Nearly identical to our error - package can't find the specified paths
   - Problem with the exports field in package.json not correctly mapping to dist files
2. Issue ERR_MODULE_NOT_FOUND When Importing from proxyProvider Without .js Extension #440: ERR_MODULE_NOT_FOUND When Importing from proxyProvider Without .js Extension #440
   - Similar module not found error
   - Workaround: add .js extension to imports (though this won't help in our case)
3. Issue Module Resolution Error in ESM: Unable to Resolve @modelcontextprotocol/sdk/types.js #459: Module Resolution Error in ESM: Unable to Resolve @modelcontextprotocol/sdk/types.js #459
   - Another module resolution issue in ESM context
   - Very similar error pattern to what we're experiencing

The core issue appears to be in how the SDK is packaged and exported:

1. The package.json has an exports field that points to:
   "exports": {
   "./": {
   "import": "./dist/esm/",
   "require": "./dist/cjs/*"
   }
   }
2. However, when installed, the dist directory is missing entirely, causing any imports
   to fail with ERR_MODULE_NOT_FOUND
3. This is likely happening because the package is being installed directly from GitHub
   without being properly built first.