Approval without runtime control leaves a gap between what was reviewed and what actually executes. A server can change version, expand permissions, or behave differently after approval, and the original review no longer reflects live risk. The result is unmanaged privilege drift.
Why This Matters for Security Teams
Approval-only MCP governance assumes the server that was reviewed is the same server that later executes. That assumption breaks quickly in agentic environments, where tool permissions, model behavior, connector scopes, and backend dependencies can change after sign-off. Once runtime drift begins, the approval record becomes historical evidence rather than a control, and the agent can still reach data or actions that were never intended.
This is why NHI governance has to include live behaviour monitoring, not just intake review. NHIMG’s Top 10 NHI Issues and the Ultimate Guide to NHIs, Regulatory and Audit Perspectives both reflect the same operational reality: unmanaged credentials and overbroad privileges do not stay bounded once a workload begins chaining actions across systems. The problem is not only whether MCP was approved, but whether the live server still matches the approved risk profile.
Current guidance from NIST Cybersecurity Framework 2.0 and the OWASP Agentic AI Top 10 points toward continuous monitoring and context-aware control, but there is no universal standard for MCP runtime governance yet. In practice, many security teams encounter privilege drift only after an agent has already exercised a new tool path, rather than through intentional change management.
How It Works in Practice
Effective MCP governance treats approval as the start of control, not the finish line. The runtime question is simple: what can the server do right now, with this version, this scope, this identity, and this context? That means the control plane should continuously validate server identity, version, declared tools, token scope, and policy conditions before allowing a request to execute. If any of those elements change, the request should be re-evaluated or blocked.
In practice, teams combine several controls:
- Version and configuration pinning so the approved server image or package is the one actually running.
- Short-lived credentials and scoped tokens so a server cannot keep inherited access indefinitely.
- Policy-as-code at request time, using runtime evaluation rather than one-time approval.
- Logging that ties each MCP action to a specific server identity, tool call, and decision outcome.
- Periodic re-attestation when the server’s tool list, dependency chain, or permissions change.
This is especially important for agentic workloads because tool use is dynamic. An MCP server may be approved for read-only retrieval, then later receive an update that enables write actions, data export, or downstream API calls. That change is not a paperwork issue, it is a live authorization issue. The State of Non-Human Identity Security shows how often organisations lose visibility once identities and entitlements become operational, and that pattern applies directly to MCP servers that evolve after review. The same risk is echoed in OWASP Top 10 for Agentic Applications 2026, which emphasises runtime abuse paths over static trust decisions.
These controls tend to break down in fast-moving developer environments where servers are rebuilt frequently, tool manifests are generated dynamically, or permissions are inherited from loosely governed service accounts because the approved state and the live state diverge too quickly to rely on manual review alone.
Common Variations and Edge Cases
Tighter runtime control often increases operational overhead, requiring organisations to balance safer execution against deployment speed and developer friction. That tradeoff becomes sharper in environments that rely on internal marketplaces, self-service agent builders, or rapidly changing plugin ecosystems.
One common edge case is an MCP server that is technically unchanged but behaves differently because a downstream model, API, or data source changes. Approval still exists, but the effective risk does not. Another edge case is delegated administration, where a platform team approves the server and a separate product team later expands the tool catalog without re-review. Best practice is evolving here: approval workflows should explicitly include change triggers, not just initial registration.
Another issue is visibility across third-party integrations. If the server can invoke external services or move data through chained tools, runtime monitoring must cover those dependencies as well. The Ultimate Guide to NHIs is useful for lifecycle framing, but MCP governance needs an extra layer because the behavioural surface can change without a formal identity change. That is why the emerging consensus across NIST Cybersecurity Framework 2.0 and OWASP Agentic AI Top 10 is to enforce continuous verification, not approval-only trust.
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, CSA MAESTRO and OWASP Non-Human Identity Top 10 address the attack and risk surface, while NIST AI RMF and NIST CSF 2.0 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Agentic AI Top 10 | A03 | Runtime tool abuse is a core agentic AI risk when approvals go stale. |
| CSA MAESTRO | GOVERN | MAESTRO stresses governance over autonomous workflows and changing tool access. |
| NIST AI RMF | GOVERN | AIRMF addresses accountability and monitoring for AI systems with changing behaviour. |
| NIST CSF 2.0 | DE.CM | Continuous monitoring is needed to detect privilege drift after approval. |
| OWASP Non-Human Identity Top 10 | NHI-03 | Static approval fails when NHI credentials and permissions drift after issuance. |
Tie MCP change control to live policy checks and re-attestation on every material update.
Related resources from NHI Mgmt Group
Deepen Your Knowledge
Reviewed and updated by the NHIMG editorial team on August 2, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
