03.01 · Concept
What MCP actually solves
Say what problem MCP solves that a bag of function definitions does not.
MCP standardises the boundary between AI clients and external systems, so tools and context can be discovered, called, permissioned, and maintained through a common protocol. A list of function schemas can describe callable operations, but it does not provide the integration contract needed across many apps, teams, providers, and environments.
What this lesson answers
- what problem does MCP solve beyond function calling
- when should an AI integration use MCP
- how is MCP different from tool schemas
Notes
A bag of function definitions tells a model that some callable things exist, but it does not solve the larger integration problem. Real applications need a repeatable way to discover tools, understand available resources, pass context, handle permissions, connect to many providers, and keep those connections stable as clients and servers change. MCP is trying to standardize that boundary: an AI application can speak one protocol to many context and tool providers instead of learning a new custom integration for each one.
A useful mental model is USB-C for AI context, not because every device…
Common questions
- Is MCP just function calling with different packaging?
- No. Function calling usually means giving a model a set of callable operations inside one application flow. MCP defines a client-server protocol around tools and context sources, including discovery, transport, lifecycle, reuse, and separation of responsibilities. It is about making integrations stable across systems, not just naming functions.
- What does MCP change for application integration?
- It gives AI applications a common way to connect to external systems instead of writing bespoke glue for every database, repository, file store, tracker, or internal service. The server wraps the external system and exposes capabilities in a structured form, while the client can discover and use them through the same protocol.
- When is a bag of function definitions enough?
- A small, local feature with a fixed set of functions may not need MCP. Function definitions are often fine when one application owns the whole flow and the integration is not reused elsewhere. MCP becomes more useful when capabilities need to be discoverable, shared, permissioned, and maintained across multiple clients or teams.