Because the server often becomes part of the authorisation path, not just the application path. That means the server may need to manage tokens, validate upstream identity, and enforce tool-level permissions while still behaving like a normal service. IAM teams should expect server-side token handling to be governed like other non-human identity infrastructure, not treated as a minor integration detail.
Why This Matters for Security Teams
MCP servers change the governance boundary because they often mediate tool use, token flow, and upstream identity validation at runtime, not just request forwarding. That shifts them from “another integration service” into a control point that can create, narrow, or accidentally expand access. The issue is less about the protocol itself and more about the server’s new role in the identity chain, which is why NHI governance and application security now overlap.
IAM teams are used to static entitlements tied to users or service accounts, but MCP servers introduce a more dynamic pattern: the server may need to authenticate agents, manage downstream credentials, and decide whether a tool call is allowed in the current context. Current guidance from OWASP Agentic AI Top 10 and NHIMG’s Ultimate Guide to NHIs both point to the same operational reality: identity controls fail when a service becomes an authorization broker without being governed like one.
In practice, many security teams encounter credential sprawl and over-scoped tool access only after an MCP server has already been deployed into a production workflow.
How It Works in Practice
An MCP server typically sits between an agent and the tools or systems the agent wants to use. That means the server may receive an upstream identity assertion, translate it into a downstream token, and then enforce which tools, datasets, or actions are available for that task. This is where classic IAM assumptions break down. A role assigned once at deployment time rarely captures what an autonomous or semi-autonomous agent is trying to do at runtime.
Better practice is to treat the MCP server as a workload identity boundary and a policy enforcement point. That means using short-lived credentials, minimizing secret persistence, and evaluating access decisions at request time rather than relying only on pre-defined groups or fixed roles. Guidance from the NIST Cybersecurity Framework 2.0 supports this kind of least-privilege discipline, while the State of MCP Server Security 2025 shows why the control surface matters: 53% of MCP servers expose credentials through hard-coded values in configuration files.
- Issue workload identity to the server and the agent separately, so each hop is cryptographically attributable.
- Use JIT, ephemeral tokens for tool access and revoke them when the task ends.
- Apply policy-as-code for tool-level authorization rather than embedding permissions in application logic.
- Log token exchange, tool invocation, and permission decisions as identity events, not just app telemetry.
This model works best when the MCP server can validate context in real time and when downstream systems support scoped delegation. These controls tend to break down when the server is forced to cache long-lived secrets for legacy backends because static credentials reintroduce standing privilege and make revocation slow.
Common Variations and Edge Cases
Tighter server-side authorization often increases operational overhead, requiring organisations to balance fine-grained control against deployment complexity and latency. That tradeoff is especially visible in MCP environments that aggregate many tools, because one server may need different trust and permission rules for each backend.
There is no universal standard for how every MCP deployment should handle delegation yet. Current guidance suggests starting with the smallest viable trust scope, then expanding only where policy can be enforced consistently. NHIMG’s Top 10 NHI Issues highlights the broader pattern: excessive privilege, poor rotation, and weak visibility remain common across non-human identities, and MCP servers can amplify all three if they broker access without strong lifecycle controls.
Edge cases appear when a server supports multiple agents, federated tenants, or delegated toolchains across teams. In those environments, a single role mapping is usually too blunt, and even good access review processes can miss short-lived grants. The 52 NHI Breaches Analysis is a useful reminder that identity failures often emerge from weak operational hygiene rather than novel exploits. Security teams should treat shared MCP infrastructure as a high-value NHI control plane, not as a neutral middleware layer.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP Agentic AI Top 10 and CSA MAESTRO address the attack and risk surface, while NIST AI RMF set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Agentic AI Top 10 | A3 | Covers tool misuse and authorization failures in agentic flows. |
| CSA MAESTRO | T1 | Addresses trust boundaries and policy enforcement for agentic systems. |
| NIST AI RMF | GOV-2 | Supports accountability for AI-enabled systems and decision traces. |
Assign ownership for MCP authorization decisions and retain evidence for reviews and incidents.
Related resources from NHI Mgmt Group
Deepen Your Knowledge
Reviewed and updated by the NHIMG editorial team on June 8, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
