In app-to-app integration, the process of each application individually registering as an OAuth client for every other application has been a significant manual burden.
MCP Specification to Include OAuth Dynamic Client Registration (DCR) and More
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In response, Anthropic and OpenAI have incorporated Dynamic Client Registration (DCR)—an OAuth extension—into the MCP specification. DCR is a mechanism that allows an application to dynamically register itself with an unknown application, enabling it to initiate an OAuth flow immediately.
Furthermore, a mechanism called Client ID Metadata Documents (CIMD) exists. This allows an OAuth flow to be initiated without any prior registration work by self-hosting OAuth client data via a URL.
Val Town, a vibe coding platform, mentioned these technologies through its MCP server construction process. The company explained that by using authentication providers that support DCR, such integrations become possible regardless of the underlying infrastructure.
Source: Connecting every app to every other app (Hacker News Frontpage, 2026-09-05)