What is MCP?

IBM z/OS Connect uses Model Context Protocol (MCP) to allow Large Language Models (LLMs) to access programs and data on z/OS using existing z/OS® Connect APIs.

zosConnect-3.0 Applies to zosConnect-3.0.

What is MCP?

Model Context Protocol (MCP) is an open protocol that is designed to enable Large Language Models (LLMs) and AI agents to interact with external systems in a standardized way. In the context of z/OS Connect, MCP allows LLMs to invoke existing z/OS APIs to access programs.

When MCP is enabled in z/OS Connect, each API operation is exposed as an MCP tool. These tools can be discovered and invoked by AI agents to retrieve real-time data or trigger business logic on z/OS.

Figure 1. MCP with z/OS Connect
An image to show the flow AI agent, through MCP to z/OS Connect and the data and applications

Why MCP?

LLMs are powerful, but they lack access to current system data and cannot perform actions on their own. MCP bridges this gap by standardizing how AI agents request and receive information from external systems.

LLMs are inherently stateless and lack access to real-time system data or the ability to perform actions. MCP addresses this limitation by:

  • Standardizing tool invocation - AI agents can query available tools and invoke them using a consistent protocol.
  • Enabling agentic workflows - LLMs can reason about which tools to use based on context and dynamically interact with enterprise systems.

How MCP works

  1. Tool Registration

    When an API is deployed in z/OS Connect, each operation is automatically registered as an MCP tool.

  2. Client-Server Interaction

    An MCP client (typically an AI agent or orchestration layer) sends requests to the MCP server running inside z/OS Connect. The server uses Streamable HTTP transport to handle requests and responses.

  3. Tool Discovery and Invocation

    Clients can:

    • List available MCP tools
    • Retrieve metadata about each tool
    • Invoke tools with structured input and receive structured output

  4. Dynamic Updates

    MCP tool availability is automatically updated when APIs are deployed or undeployed, helping ensure accurate discovery.

MCP in z/OS Connect

With MCP enabled:

  • All deployed API operations are automatically registered as MCP tools.
  • The MCP server uses Streamable HTTP transport to communicate with clients.
  • Tool lists are dynamically updated when APIs are deployed or removed.

Learn more