Webhook support for background notifications

[kentcdodds]

Pre-submission Checklist

• I have verified this would not be more appropriate as a feature request in a specific repository
• I have searched existing discussions to avoid duplicates

Your Idea

To keep it simple, I think we need to standardize on async tasks and eventing. A user may want to trigger an MCP request that takes time to complete and can't be done within the life of a single request (particularly if their architecture does not support SSE).

There's a bit about this here: https://github.com/orgs/modelcontextprotocol/discussions/314

Notifications: Specifying endpoints or mechanisms for the service to push information back to the client/AI (potentially via WebSockets, webhooks, SSE interpreted by the client, etc.).

I think we need to go the webhooks route because some requests could day minutes, hours, or days.

Scope

• Protocol Specification
• SDK Features
• Documentation
• Developer Experience
• Other

[tadasant]

A few related discussions:

• Implement async patterns with Resources
• Webhooks proposal
• Stream resumeability that could be implemented with webhooks

I think each of these three proposals is trying to solve the same problem raised here (how MCP should deal with long running tool calls).

[kentcdodds]

I didn't find those discussions because they're on the modelcontextprotocol repo instead of the org discussions. It's unclear to me where to post stuff like this. But I'll defer to those because they're already ongoing. Thanks!

[tadasant]

Yeah fair it's not obvious. As some loose guidance, I'd say potential spec change discussions belong on the spec's repo (where those links are), vs. general ideas, projects, questions, etc are better here in the top level.