MCP Client Quick Start

Background

Usually, compared with MCP Server, MCP Client will be more complex. Here’s a breakdown to clarify why:

MCP Server: Lightweight and Declarative

Purpose: Exposes and hosts tools with metadata in a standardized format.

Responsibilities:

• Serves tool definitions
• Provides a registry of capabilities (e.g. tool name, input/output schema).

Key Traits:

• Stateless, read-only, low logic overhead.
• No need to interact with LLMs or orchestrate execution.

MCP Client: Smart, Interactive, LLM-Aware

Purpose: Acts as the bridge between the LLM and tool invocation infrastructure.

Responsibilities:

• Queries the MCP Server to fetch tool metadata.
• Integrates with an LLM, providing it with the tool schema in MCP format.
• Parses LLM outputs to detect tool invocations (tool_use events).
• Calls tools using the provided input schema and passes results back to the LLM.
• Optionally manages conversational context, error handling, fallbacks, and multi-step toolchains.

Key Traits:

• Stateful, interactive, and logic-heavy.
• Needs tight coordination between…