A defined interface for your existing system
MCP provides a common interface for tools and resources. The project defines which operations your application will offer and how they behave when a request is incomplete, unauthorized or repeated.
- Connected systems
- MCP + REST API
- Data flow
- A supported AI client calls the MCP server, which validates the request and invokes the permitted application API. Results return to the requesting client. The underlying website or business system owns records, permissions and accepted state changes.
Map existing operations
Inspect the available API and name the records, fields and actions the assistant needs. A lookup and a record update receive separate tool definitions. An older interface may need application work before an AI connection is practical.
Build the server boundary
Define typed inputs, limited responses and server-side authorization for each operation. Check the calling identity against the downstream system’s permissions. Tool descriptions explain permitted use; they do not replace access controls.
Handle retries and failures
Return useful validation errors and distinguish an unsuccessful request from an unknown result. For write operations, design request identifiers or confirmation checks where the application supports them, so a retry does not silently repeat a business action.