Evolving OAuth Client Registration in the Model Context Protocol

The Model Context Protocol (MCP) has adopted OAuth 2.1 as the foundation for its authorization framework. A key part of the authorization flow that MCP is particularly reliant on is client registration. This is especially important in a world where clients and servers don’t have a pre-existing relationship - we can’t assume that we will always know which MCP clients will connect to which MCP servers. This design highlights two challenges that need to be addressed: ...

August 22, 2025 · 10 min · Paul Carleton (Core Maintainer)