MCP server
An MCP server is a program that exposes tools, resources, and prompts to AI agents over the Model Context Protocol. Each tool carries a name, a description, and an input schema the agent uses to decide when and how to call it. An agent typically connects to several servers at once.
Servers range from official first-party integrations to single-file community projects, and an agent extends the same protocol-level trust to all of them. The description and schema a server publishes are rendered into the model's context, which is why a malicious server is not just a bad dependency but a voice inside the agent's reasoning. Vetting servers, screening their schemas, and governing their calls are distinct controls; conflating them is how gaps happen.
Related
Shrike governs AI agent actions in real time: every command, query, and tool call evaluated against policy before it executes. Start with what is action governance or the quickstart.