Terminology

Agent (Client + Host)

In MCP:

• The client is the software entity that connects to the MCP server to receive context and tools.

• The host is the environment that provides that context, typically an application or orchestration layer that knows the patient, user, and FHIR server.

In many practical implementations, the host and client are in the same system, or at least tightly coupled. For clarity and simplicity, SHARP refers to this unified role as the agent, the logical entity that initiates an MCP session and consumes its output.

MCP Server

A remote server that implements the Model Context Protocol and is responsible for:

• Providing tool definitions
• Accepting context inputs
• Streaming results back to the agent

SHARP on MCP will define best practices and a standard structure for building these servers in a decoupled, reusable way for healthcare.

Context

A structured set of parameters that describe the environment, data sources, patient, and user identity relevant to a particular request.

In SHARP on MCP, context is typically passed via HTTP headers (e.g., X-FHIR-Server, X-Patient-ID, X-Access-Token).

Tool

A callable function or API exposed by the MCP server that an agent can invoke as part of its reasoning. Tools include metadata (e.g., name, parameters, return types) that the agent can use to determine how and when to call them.

Invocation

The process by which a host or agent sends a request to an MCP server, including context, and receives streamed output and tool definitions.

SSE/Streamable HTTP

TODO - Transports - Model Context Protocol

FHIR Server

A standards-based data source conforming to HL7 FHIR, commonly used in healthcare environments to store and access clinical data. MCP servers following SHARP on MCP are designed to plug into any FHIR-compliant system.

LLM (Large Language Model)

TODO