---
title: MCP Gateway
slug: kronpam-reference-guide-3-9-0/mcp-gateway
docTags: 
createdAt: 2026-10-14T13:48:00.689Z
---

The Kron PAM MCP Gateway brings the traffic between artificial intelligence (AI) clients and Model Context Protocol (MCP) servers under Kron PAM control. AI clients connect to a single gateway endpoint instead of the address of each MCP server. The gateway authenticates the user, checks the Realm authorization of the user for the requested MCP server, forwards the request only when access is allowed, and writes every step to an audit trail.

Without the gateway, AI clients call MCP servers directly, and each client configuration stores server addresses and credentials locally. In that model, Kron PAM cannot show who accessed which MCP server, which tool they called, or whether the access should have been allowed. The MCP Gateway makes Kron PAM the control point for this traffic, so administrators grant, revoke, and audit MCP access from the same interface that they use for other privileged access.

**Key Capabilities**

- **Single control point** — AI clients connect only to the gateway endpoint. Users never see the upstream URL or the outbound credential of an MCP server.
- **User-based authentication** — Users sign in through a browser with their Kron PAM credentials. Existing multi-factor authentication (MFA) rules continue to apply.
- **Realm-based authorization** — Administrators connect user groups to MCP Server Groups through Realms. The gateway evaluates the Realms on every request, so access changes take effect without a new sign-in.
- **Tool catalog visibility** — Administrators view the tools that each MCP server exposes.
- **Full auditability** — The gateway records authorization decisions, forwarded requests, and returned responses on the **MCP Gateway Logs** page.

### Gateway Tools

The MCP Gateway appears in the AI client as a single MCP server. The gateway exposes the four tools listed in the following table, and the AI client reaches the tools of the registered MCP servers through them.

| **Tool**        | **Description**                                                                                                              |
| --------------- | ---------------------------------------------------------------------------------------------------------------------------- |
| gateway\_login  | Starts a gateway session. When no valid session exists, the tool returns a sign-in link to the Kron PAM authentication page. |
| list\_tools     | Lists the MCP servers and the tools that the Realms of the current user authorize.                                           |
| call\_tool      | Runs a tool on an authorized MCP server and returns the result.                                                              |
| gateway\_logout | Ends the gateway session and invalidates the session token.                                                                  |

### Request Flow

An MCP request passes through five stages:

1. The AI client sends the request to the gateway endpoint of Kron PAM.
2. The gateway validates the gateway session of the user. When no valid session exists, the gateway returns a sign-in link instead of processing the request.
3. The gateway identifies the target MCP server and evaluates the enabled Realms against the current user group and MCP Server Group memberships.
4. When at least one Realm allows access, the gateway removes the authentication data of the user from the request and forwards the request to the MCP server with the outbound authentication method of the server. When no Realm allows access, the gateway returns a generic access denied response and does not contact the MCP server.
5. The gateway returns the response to the AI client and writes every stage to the MCP Gateway Logs under the same session ID.