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 AI 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:
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Intercepts the tool invocation.
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Extracts Identity, context, tool, and parameter information.
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Requests an authorization decision from PlainID.
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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.