When should security teams move MCP settings into shared referenced resources?

Why This Matters for Security Teams

MCP settings belong in shared referenced resources the moment they stop being unique to one server. The practical trigger is reuse: the same identity provider, telemetry backend, or tool allow list appearing in more than one manifest. At that point, keeping configuration local creates drift, makes reviews inconsistent, and turns a change request into a fleet-wide patching exercise. This is especially important for agentic workloads, where the OWASP Top 10 for Agentic Applications 2026 and NHIMG research on AI agents: the new attack surface both point to the same operational risk: access paths change faster than governance can keep up.

NHI Management Group has also documented how quickly shared identity and tool dependencies become a control issue. In The State of Non-Human Identity Security, only 1.5 out of 10 organisations reported high confidence in securing NHIs, which reflects how fragile manual ownership becomes once settings are duplicated across systems. The right question is not whether a setting is “important enough” to centralise. It is whether multiple MCP servers depend on the same trust anchor, policy, or integration point. In practice, many security teams only discover the duplication problem after an access change, outage, or audit finding has already exposed it.

How It Works in Practice

Shared referenced resources work best when they become the canonical source for settings that are meant to be identical across servers. Typical examples include identity provider metadata, TLS or certificate material, logging destinations, approved tool catalogs, and common network or environment settings. The server manifest should reference those resources, not copy them. That makes policy review easier because the operator evaluates one object instead of hunting through many manifests for subtle differences.

For security teams, the implementation pattern is straightforward:

• Identify settings that are reused across two or more MCP servers.
• Separate stable infrastructure values from server-specific behavior.
• Move the stable values into a referenced resource with clear ownership.
• Apply change control to the shared object, not each server copy.
• Review references for scope, expiry, and allowed use cases before rollout.

This aligns with current guidance from OWASP Agentic AI Top 10, which treats inherited trust and tool access as high-risk when they are not centrally governed. It also matches the operational lesson in NHIMG’s OWASP Agentic Applications Top 10: once agents can chain tools, duplicated settings become an amplification path for misconfiguration. Shared resources are not just a cleanliness improvement. They create a reviewable control plane for identity, telemetry, and tool access across the MCP estate. These controls tend to break down when teams allow each server to override shared settings locally, because the resulting exceptions are hard to inventory and even harder to audit consistently.

Common Variations and Edge Cases

Tighter centralisation often increases coordination overhead, requiring organisations to balance consistency against local autonomy. That tradeoff is real, especially where one MCP server is used by a regulated workload and another supports rapid experimentation. Current guidance suggests shared referenced resources should cover the common trust layer, while narrowly scoped exceptions remain local only when there is a documented operational reason.

There is no universal standard for this yet, so teams should be explicit about what belongs in the shared layer versus the server layer. A good rule is to centralise anything that would cause security drift if edited differently in two places, such as issuer metadata, common deny lists, telemetry endpoints, or baseline tool approvals. Keep server-specific entries for workload-specific tools, unique network paths, or special test environments.

Edge cases also appear when different teams own different servers but share the same control boundary. In that scenario, shared resources reduce duplicate approvals, but they also require stronger change governance and clear blast-radius limits. That is where policy-as-code and versioned references matter most, because they let operators verify that every consumer is still pointing at the approved object. Where agents operate in fast-changing or multi-tenant environments, the safest pattern is to centralise the trust primitives and leave only the truly unique settings local.

Related resources from NHI Mgmt Group

• How should security teams authenticate AI agents in enterprise environments?
• How should security teams implement Client ID Metadata Documents?
• How should security teams govern shared AI agents that can inherit hidden proxy settings?
• How should security teams decide whether to move SOC operations off a shared IT platform?