Webhooks

[pantanurag555]

Motivation and Context

This is draft PR for the changes discussed in specification discussion #523.

How Has This Been Tested?

Tested by setting up a webhook, client and server locally. The webhook received all messages when the server was setup with streamable http. It was tested for both json_response True and False. All units tests succeeded.

Breaking Changes

None

Types of changes

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

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
• [x] I have added or updated documentation as needed