An MCP Gateway Registry is a catalog that records available Model Context Protocol gateways, the tools they expose, and the policies that govern access to them. It helps AI agents and operators discover approved connections, manage trust boundaries, and track which services can be reached through controlled protocol mediation.
What an MCP Gateway Registry does
An mcp gateway Registry is the discovery and governance layer around approved Model Context Protocol gateways. It records what gateways exist, what tools they expose, and the access policies that shape how AI agents and operators can reach them.
That registry function matters because the gateway is not just a directory entry. It is the place where an organisation defines which mediated connections are acceptable, which services are visible, and which paths remain blocked until they meet policy. In practice, it becomes the control point between an agent’s intent and a real downstream action.
How it fits into MCP governance
The registry sits alongside the gateway as part of the control plane for MCP use. A gateway mediates protocol access, while the registry gives teams a structured view of those gateways and their boundaries, which is especially useful when multiple agents, teams, or environments share the same protocol ecosystem.
Because the registry tracks policy as well as inventory, it can support trust decisions such as which tools are approved for production use, which are limited to specific environments, and which require additional review before exposure. For governance teams, that makes the registry a practical source of truth rather than a simple service list.
Its value increases as the number of gateways grows. Without a registry, approved connections tend to become tribal knowledge, which makes it harder to reason about what an agent can actually reach versus what it was merely intended to reach.
What it records and why that matters
A useful registry typically captures gateway identity, the tool or service inventory behind each gateway, and the policy boundaries attached to access. That combination lets operators understand not just where a gateway points, but what authority it confers when an agent uses it.
This distinction is important because tool exposure is a security boundary. A gateway that exposes a narrow, reviewed toolset is very different from one that provides broad access to operational systems, data services, or sensitive workflows. The registry helps keep those differences visible.
The concept also intersects with agent behavior. If an agent can discover only approved gateways through the registry, the organisation can constrain reachable capabilities without having to redesign every downstream service. That is why registry quality affects both operational safety and policy enforcement.
NHIMG research on The State of MCP Server Security 2025 found that only 18% of MCP server deployments implement any form of access scoping for tool permissions, underscoring how easily gateway exposure can outpace governance.
Common failure modes
The most common weakness is treating the registry as passive inventory instead of an enforced trust boundary. When that happens, teams may document gateways but still allow broad tool access, stale entries, or unclear ownership over what an agent can invoke.
Another failure mode is registry drift. If the listed gateways, tool scopes, and policy rules fall out of sync with the real environment, operators may believe a path is controlled when it is actually overexposed. That gap is especially risky in agentic environments, where automated discovery can quickly amplify a mistaken trust decision.
Registry design also becomes brittle when it cannot distinguish between approved internal gateways and externally supplied or third-party ones. In that case, the registry may look complete while still leaving material third-party exposure untracked.
Risk and Threat Considerations
An MCP Gateway Registry can reduce exposure, but only if it is authoritative and kept in sync with actual gateway behavior. If the registry is stale or incomplete, an organisation may overestimate its control over which tools and services an agent can reach.
Failure mechanism: Drift between the registry, the gateway, and the real tool surface can allow excessive access, invisible expansion of trust boundaries, or continued exposure of retired or misclassified gateways.
Impact: Agents may reach systems beyond intended scope, sensitive tools may remain discoverable, and policy enforcement may fail at the exact point where the organisation believes access is being constrained.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP Non-Human Identity Top 10, OWASP Agentic AI Top 10 and OWASP API Security Top 10 address the attack and risk surface, while NIST SP 800-53 Rev 5 and NIST Zero Trust (SP 800-207) set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Non-Human Identity Top 10 | NHI-05 — Overprivileged NHI | Gateway registries govern which non-human callers can reach tools and services. |
| NHI-03 — Vulnerable Third-Party NHI | A registry must track third-party gateways and their trust boundaries. | |
| Recommendation — Limit registry-exposed gateways to the least privilege needed for each approved agent path. Inventory third-party gateways and require review before exposing them through the registry. | ||
| OWASP Agentic AI Top 10 | ASI03 — Identity & Privilege Abuse | Registry policy determines what agents are authorized to discover and invoke. |
| ASI02 — Tool Misuse | The registry defines which tools an agent can legitimately reach through mediation. | |
| ASI04 — Agentic Supply Chain Vulnerabilities | Gateway registries are part of the trusted supply path for agent tool access. | |
| Recommendation — Constrain agent-visible gateways so discovery cannot expand privilege beyond approved policy. Publish only approved tools in the registry and keep high-risk tools behind explicit policy checks. Validate gateway provenance and ownership before adding it to the registry. | ||
| NIST SP 800-53 Rev 5 | AC-3 — Access Enforcement | A registry that governs gateway access is directly about enforcing access decisions. |
| CM-8 — System Component Inventory | The registry functions as an inventory of gateways and exposed tools. | |
| AU-2 — Event Logging | Registry changes and gateway approvals need auditability to preserve trust boundaries. | |
| Recommendation — Enforce registry-backed access rules so only approved gateways and tools are reachable. Maintain an accurate inventory of gateways, tools, and policy boundaries in the registry. Log registry updates and approval changes for later review and investigation. | ||
| NIST Zero Trust (SP 800-207) | Zero Trust Architecture | The registry supports explicit trust boundaries and verified access paths. |
| Recommendation — Treat each registered gateway as a verified access point and avoid implicit trust between agents and tools. | ||
| OWASP API Security Top 10 | API9 — Improper Inventory Management | A gateway registry is an inventory of exposed protocol endpoints and tools. |
| Recommendation — Keep gateway inventory complete and remove stale or shadow entries from the registry. | ||
Practitioner Guidance
Governance implication: Treat the registry as a control plane asset, not a documentation artifact. Its ownership should include clear accountability for what gets listed, who approves it, and when policy state must be updated.
What to watch for: Inconsistent tool inventories, unclear gateway ownership, or a registry that cannot explain why a gateway is approved are strong signals that the control boundary is weakening. In MCP environments, discovery and approval should stay tightly coupled.
For teams building out gateway governance, the registry should answer one practical question without ambiguity: if an agent discovers this path, is it truly approved to use it?
Related resources from NHI Mgmt Group
- What is the difference between an MCP registry and an MCP gateway?
- What breaks when namespace ownership is not verified in an MCP registry?
- Who should be accountable when a federated MCP registry exposes the wrong server or auth metadata?
- How should security teams govern access to MCP registry-discovered servers?
Deepen Your Knowledge
Reviewed and updated by the NHIMG editorial team on September 24, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
