Practical MCP with FastMCP & LangChain

Prompts (Server Side)

Prompts are structured conversation blueprints that a server makes available to a client. They are not actions, and they do not fetch or modify data. Their role is to define how an interaction with the AI should be framed.

Think of a prompt as a prepared conversation setup. It tells the AI what role to play, what tone to adopt, and how to structure its response for a specific task.

For example, a server might expose a "Code Review" prompt. When the user selects a "Code Review Mode" button or writes a slash command like /review in a chat interface, the host retrieves a predefined template from the server.

That template could look conceptually like this:

System instruction: "You are a senior software engineer performing a strict code review. Focus on correctness, readability, performance, and security. Provide concrete suggestions. Be precise and structured."

User template: "Please review the following code and provide feedback grouped