MCP review

Server Primitives: Tools, Resources, and Prompts

These three primitives define how different parts of an application interact with the core AI model and the user interface.

**1. Tools**

• Control: Model controlled.
• Function: The AI model (Cloud) is responsible for deciding when to execute a tool.
• Purpose: Used to add external capabilities to the Cloud/Model (e. g. , executing JavaScript code).
• Implementation: Implement tools within an MCP server or consume them via an MCP client.

**2. Resources**

• Control: Application controlled.
• Function: The application's code decides when it needs data from a resource and executes it.
• Purpose: Used to fetch data and provide content for the UI (e. g. , fetching documents from Google Drive to show autocomplete options).
• Implementation: Implement resources within an MCP server.

**3. Prompts**

• Control: User controlled.
• Function: The user decides when a prompt workflow should run (e. g. , clicking a UI button or using a slash command).
• Purpose: Used to implement predefined workflows.
• Implementation: Implement prompts within an MCP server.

Summary of Roles

• Tools: Serve the Model.
• Resources: Serve the Application.
• Prompts: Serve the User.

Takeaways

• Tools are model-controlled and provide external capabilities to the AI.
• Resources are application-controlled and fetch data to support the user interface.
• Prompts are user-controlled and implement predefined workflows triggered by the user.
• The three primitives (Tools, Resources, Prompts) define how different parts of an application interact with the core AI model.