Agent identity vs MCP gateway
An identity platform answers who the agent is and what it may access, with short-lived scoped tokens instead of shared keys. A gateway enforces that at each tool call and records it. They overlap on authentication and credentials; neither finds shadow agents, and neither detects injected instructions on its own. Identity is the foundation, the gateway is where it is applied to MCP.
Side by side
Marks follow the shared criteria. Agent identity and secrets and MCP gateway are in the main comparison table.
| Dimension | Agent identity and secrets | MCP gateway |
|---|---|---|
| Authentication | Strong: the core of it. | Strong: applies your identity provider. |
| Credential handling | Strong: vaulted, short-lived, scoped. | Strong: brokered per request. |
| Policy depth | Partial: scopes and conditional access. | Partial to strong: tools and arguments. |
| Audit | Partial: sign-ins and access decisions. | Strong: each tool call. |
| Shadow agents | None: unregistered agents have no identity. | None: only routed clients. |
How they fit
OAuth token exchange lets a gateway trade a user's sign-in for a narrower token for one upstream server. Microsoft Entra Agent ID and Aembit approach this from the identity side; gateways approach it from the call path. Runlayer syncs your identity provider's groups, gives agents their own accounts with on-behalf-of tokens, and enforces the overlap of agent and user permissions in its gateway.
Which suits whom
- Microsoft-centred with agents mostly in Copilot StudioEntra Agent ID for identity, with a gateway for MCP tool calls.
- Agents across many clients and MCP serversA gateway that carries identity to each call; Runlayer does both.
Sources
- RFC 8693: OAuth 2.0 Token Exchange · IETF
- Authorization · Model Context Protocol specification, 2025-11-25
- What is Microsoft Entra Agent ID? · Microsoft Learn
- MCP server access (MCP Identity Gateway) · Aembit documentation
- Teams and directory sync · Runlayer documentation