---
title: "MCP Gateway"
slug: "mcp"
status: "custom"
updated: 2026-10-21T07:16:35Z
published: 2026-10-21T07:16:35Z
canonical: "docs.plainid.io/mcp"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.plainid.io/llms.txt
> Use this file to discover all available pages before exploring further.

# MCP Gateway

The **MCP Gateway (MCP GW)** is a core component of **PlainID Edge**, responsible for securing, centralizing, and enforcing access to MCP-based tools in Agentic Identity Control environments.

Its primary role is to act as a **Policy-enforced control point** between AI agents and the organization’s MCP servers. Instead of agents connecting directly to multiple MCP servers, all MCP traffic is routed through the MCP Gateway. The gateway exposes a single MCP endpoint while maintaining full visibility and control over tool discovery and execution.

The MCP Gateway enables organizations to apply fine-grained, real-time authorization to agent **Actions** without modifying existing agents or MCP servers.

## Purpose and Design Goals

The MCP Gateway addresses several common challenges in agentic systems:

- Uncontrolled tool access by agents.
- Lack of centralized governance across MCP servers.
- No enforcement point for authorization at the tool or parameter level.
- Difficulty mapping dynamic MCP environments into authorization **Policy** models.

To address these challenges, the MCP Gateway provides:

- A unified MCP access layer.
- Tight integration with the PlainID authorization engine.
- Real-time enforcement for every MCP interaction, including tool parameter evaluation.
- Continuous alignment between **Runtime** behavior and **Policy** definitions.

## Core Functionalities

### Unified MCP Entry Point

The MCP Gateway presents itself as a single MCP server to all agents.

- Agents connect only to the MCP Gateway.
- Backend MCP servers remain unchanged.
- Multiple MCP servers are abstracted behind a single endpoint.

This approach simplifies agent configuration while enabling centralized governance and control.

### MCP Server and Tool Discovery

In addition to **Runtime** enforcement, the MCP Gateway discovers and onboards MCP **Assets** into the PlainID authorization model.

#### MCP Asset Discovery

As part of PlainID Edge, the MCP Gateway connects to customer MCP servers and automatically:

- Identifies all connected MCP servers.
- Discovers available tools.
- Retrieves structural and descriptive metadata from each server.

This discovery process requires no manual registration and does not impact existing MCP server behavior.

#### AI-Based Enrichment and Classification

After discovery, PlainID Edge enriches the collected data using AI-based classifiers.

During this phase:

- Tools are semantically analyzed.
- Functional **Attributes**, such as purpose, sensitivity, category, and risk indicators, are inferred.
- **Assets** are normalized into the PlainID internal authorization schema.

This process transforms low-level MCP metadata into **Policy**-ready authorization objects.

#### Publishing to PlainID Cloud

After discovery and enrichment, the MCP Gateway publishes the processed **Assets** to **PlainID Cloud**, where they become:

- Authorization Building Blocks for **Policy** authoring.
- First-class objects in the Policy Builder.
- Continuously synchronized with the **Runtime** environment.

Security and platform teams can then define authorization rules over MCP servers and tools without additional modeling or manual configuration.

#### Continuous Synchronization

Discovery is continuous. The MCP Gateway monitors the MCP environment and:

- Detects newly added or removed MCP servers.
- Identifies changes to tools or capabilities.
- Updates **PlainID Cloud** with near real-time status changes.

This ensures that authorization **Policies** reflect the current state of the MCP ecosystem.

### Real-Time Authorization Enforcement

For every MCP request, the MCP Gateway:

- Intercepts the tool invocation.
- Extracts Identity, context, tool, and parameter information.
- Requests an authorization decision from PlainID.
- Enforces the decision inline:
  - **Allow:** Forwards the request to the target MCP server.
  - **Deny:** Blocks execution and returns an authorization error.

Enforcement occurs synchronously and transparently, with no agent-side changes required.

### Fine-Grained Control

The MCP Gateway enables authorization enforcement at multiple levels:

- MCP server level.
- Tool level.
- Tool parameter level.