Configures a descriptive user agent in all HTTP requests.

Example (Node): my-mcp-sdk/1.17.2 os/darwin#24.5.0 lang/js md/nodejs#22.13.1

Example (Browser): mcp-sdk-ts/1.17.2 os/macOS#10.15.7 lang/js

• The browser user agent looks slightly different due to the method of acquiring the platform being different than in Node. Refer to userAgent.test.ts for details.

Motivation and Context

Makes debugging client/server incompatibilities easier.

How Has This Been Tested?

Unit tests.

Breaking Changes

No breaking changes.

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

Additional context

Reference implementation for modelcontextprotocol/modelcontextprotocol#1329