Glossary — Agentic AI
What is an MCP Client?
An MCP client is the component within an AI agent or application that connects to MCP servers, discovers available tools and resources, and invokes them on behalf of the agent following the Model Context Protocol specification.
WHY IT MATTERS
In the MCP architecture, the client is the agent's gateway to external capabilities. It maintains connections to one or more MCP servers, each providing different tools, resources, or prompts. The client handles protocol negotiation, capability discovery, and request/response management.
Most agent frameworks now include MCP client support — meaning any MCP-compatible tool automatically works with any MCP-compatible agent. This decouples agent development from tool development, creating a plugin-like ecosystem.
For financial agents, the MCP client manages connections to payment tools, blockchain interfaces, and policy servers. It needs to handle authentication, connection failures, and timeouts gracefully — a dropped connection mid-transaction could be costly.
HOW POLICYLAYER USES THIS
Agents running as MCP clients can connect to PolicyLayer's MCP server to access spending policy tools — checking limits, validating transactions, and querying spending history before executing financial operations.