What Is an MCP Gateway?
Learn what an MCP Gateway is, how it fits into the Model Context Protocol stack, and how it simplifies secure agent access to APIs.
TL;DR:
An MCP Gateway is a policy enforcement and token validation layer that sits between your APIs and incoming agents.It intercepts requests, verifies MCP tokens, and ensures that only authorized, scoped, and traceable agents get through.
Think of it like an API gateway — but agent-aware.
🧠 Why You Need an MCP Gateway
As agent access grows, you need a way to:
- Accept only valid MCP tokens
- Enforce token scopes and permissions
- Apply delegation and tenancy rules
- Generate real-time audit logs
- Throttle or revoke misbehaving agents
Instead of embedding this logic inside every microservice or endpoint, an MCP Gateway centralizes enforcement.
🔐 What It Does
An MCP Gateway typically:
- Intercepts agent requests to your APIs
- Validates signed MCP tokens (e.g., JWT or similar)
- Verifies scope, delegation, expiration, and revocation status
- Logs the request for audit trail
- Enforces policy (e.g., rate limits, tenant access boundaries)
Some gateways may also:
- Handle token introspection
- Translate between legacy auth headers and MCP format
- Route traffic based on agent type or origin
📦 Where It Fits
<code>plaintextCopyEditAgent (MCP Client)
↓
MCP Gateway
↓
MCP Server (if needed for token exchange or validation)
↓
Application API / Resource Server</code>
You can think of the MCP Gateway as:
- An MCP-native API gateway
- An access firewall for machine identities
- The trust enforcement point for agent-based traffic
🛠️ Example: Prefactor’s Approach
At Prefactor, our MCP Gateway:
- Integrates with your existing API infrastructure
- Supports fine-grained policy definitions via DSL
- Validates and logs every agent interaction
- Works alongside your identity provider or token issuer
You don’t rewrite your APIs. You just deploy a layer that knows how to speak MCP.