Remote MCP servers (also called hosted MCP servers) run as cloud-based HTTP services rather than local child processes, enabling browser-based and background AI agents to access external tools without any local installation. The post explains the MCP protocol's two-sided architecture (client and server), contrasts local stdio-based servers with remote Streamable HTTP servers across dimensions like transport, authentication, scaling, and client compatibility, and details how OAuth 2.1 with PKCE replaces local environment variable secrets. CircleCI's hosted MCP server at mcp.circleci.com is used as a concrete example, showing how agents can autonomously query pipeline failures, flaky tests, and build logs by connecting to a single HTTPS URL.
Table of contents
What is MCP?What makes an MCP server “remote” (or “hosted”)?Local vs. remote MCP serversHow a remote MCP server works under the hoodConnecting an agent to CircleCI via remote MCPChoosing your CircleCI agent interfaceWrapping up178 Impressions