What is an MCP Client?

What it is

An MCP client is the side of the Model Context Protocol that connects out to external MCP servers to use their tools, data, and actions. When a product is an MCP client, it can plug into any MCP-compatible server and call the capabilities that server exposes. General-purpose assistants and developer tools are the most common MCP clients; many purpose-built vertical agents are not, because they ship with fixed native integrations instead.

How it works

The client initiates a connection to a server over a supported transport, discovers the tools, resources, and prompts the server advertises, then calls them as part of completing a task. The user or workspace controls which servers the client may connect to. Because the protocol is standardized, one client can work with many servers without custom code for each. See our related definitions of MCP and an MCP server for the wider context.

Key capabilities

• ✓Connects to external MCP servers over a standard protocol
• ✓Discovers and calls tools that servers expose
• ✓Reads resources such as files or records from connected servers
• ✓Lets users add or restrict which servers it can use
• ✓Works across many servers without per-integration code

Common use cases

• →Adding external tools to an assistant without custom integrations
• →Letting an agent pull data from a connected system at runtime
• →Extending a developer tool with third-party capabilities
• →Restricting research or actions to approved servers

How to evaluate one

• ?Does the product officially support connecting to MCP servers?
• ?Can users add their own servers, or only vendor-approved ones?
• ?What controls exist over which servers are allowed?
• ?Are connections read-only, or can the client take actions?

Frequently asked questions

Related definitions