As we kick off 2026, the landscape for AI agent service discovery has evolved into three distinct tiers. Here is a summary of the three primary options an AI agent has for discovering services to fulfill its objectives:
1. Hardcoded / Manual Configuration
The most basic method, where developers manually provide the agent with a list of tools and their JSON-schema definitions during the initial prompt or as part of the system configuration. This method is best for small or experimental projects with a limited number of tools.
- How it works: Tools are defined in a local config.json or hardcoded in the agent’s code.
- Shortcomings: Impossible to scale across an organization. If a tool's API endpoint changes, every agent using it must be manually updated.
2. Standardized Protocol (MCP Client-Server)
The Model Context Protocol (MCP) provides a "handshake" mechanism. Instead of the agent knowing the tool, it knows the MCP Server. This method is best for integrating a specialized third-party tool (e.g., GitHub) directly into an AI client (e.g., Cursor)
- How it works: The agent connects to an MCP Server via stdio (local) or SSE/HTTP (remote). Upon connection, the server sends a "list tools" response, effectively telling the agent: "Here is everything I can do for you today."
- Shortcomings: The agent still needs to know the exact address/URL of every server it wants to talk to. There is no "global search" across multiple servers.
3. Centralized Service Registry
This is the "Enterprise" tier of discovery. A registry acts as a directory across (the "Yellow Pages") between many agents and many MCP servers. This method is best for scaling adoption of AI agents within a large organization.
- How it works: MCP servers register their capabilities with the MCP Registry, enabling agents to semantically discover relevant tools at runtime. The registry then resolves the request by returning only the authorized tools the agent can use to achieve its objective.
- Shortcomings: Requires an initial setup of the registry infrastructure, though Kong’s MCP Server Generator automates the population of the registry from existing APIs.