MCP and APIs: complementary tools
MCP is not a replacement for REST APIs. It is a communication protocol optimised for AI agents. REST APIs are designed for applications that know exactly what to request. MCP is designed for agents that need to discover capabilities autonomously.
When to use MCP
For AI agents that explore
If your agent must discover which tools are available and decide which to use itself, MCP is superior.
For multi-client integrations
If you want to expose your data to multiple different AI clients, one MCP server saves you from maintaining specific integrations for each.
When to keep your REST API
For deterministic applications
If your application knows exactly what data to retrieve and in what order, a REST API is simpler, faster and more predictable.
Our recommendation: expose your data in MCP for AI agents, keep your REST APIs for your applications. Both can coexist perfectly.
How to migrate progressively
Create an MCP server that wraps your existing APIs. No need to refactor everything. Zero-risk migration, immediate benefit.
This architectural choice, and the gradual migration described here, belong to the architecture block of the AI Engineering Bootcamp.
