Gateway-managed credentials stay outside the agent and are injected only when needed for backend access. Agent-held credentials travel with the agent and can be reused, copied, or exposed if the runtime is compromised. For production MCP, gateway-managed secrets give the security team a cleaner audit and revocation boundary.
Why This Matters for Security Teams
The difference is not just where a secret lives. It changes the trust boundary, the audit trail, and how fast a compromise can spread. Gateway-managed credentials keep backend secrets in a controlled control plane, which makes revocation and logging simpler. Agent-held credentials, by contrast, move with the workload and can be copied, cached, or leaked if the runtime is exposed.
That distinction matters in MCP deployments because tool access often becomes the easiest path to lateral movement. Current guidance in OWASP Non-Human Identity Top 10 and NHIMG research on Ultimate Guide to NHIs — Static vs Dynamic Secrets both point to the same operational reality: long-lived credentials inside an agent increase blast radius and make incident response slower.
Entro Security’s LLMjacking: How Attackers Hijack AI Using Compromised NHIs found that when AWS credentials are exposed publicly, attackers attempt access within an average of 17 minutes, and as quickly as 9 minutes in some cases. In practice, many security teams discover credential exposure only after the agent has already used the secret successfully.
How It Works in Practice
Gateway-managed credentials are issued to the gateway or broker, not embedded in the agent runtime. When the agent requests an action, the gateway evaluates policy, fetches the needed secret, and forwards the request downstream. This keeps the credential out of the agent’s memory space and reduces reuse risk. It also supports tighter rotation, because the gateway can mint or retrieve short-lived access on demand rather than handing the agent a reusable secret.
Agent-held credentials place the secret inside the execution environment, so the agent can call tools or APIs directly. That pattern may be easier for prototypes, but it assumes the runtime is trustworthy for the full lifetime of the secret. For production systems, best practice is evolving toward ephemeral access, workload identity, and runtime authorisation. The operational model is closer to NIST AI Risk Management Framework principles and the agentic controls discussed in CSA MAESTRO agentic AI threat modeling framework.
- Use gateway-managed credentials when the agent only needs delegated backend access.
- Bind access to task scope, not to a reusable identity token that outlives the job.
- Prefer short TTLs and automatic revocation after task completion.
- Log gateway decisions separately from agent actions so revocation and forensics are clear.
NHIMG’s Ultimate Guide to NHIs — Lifecycle Processes for Managing NHIs reinforces that lifecycle controls only work when issuance, use, and revocation are all observable. These controls tend to break down when the agent needs direct, offline, or long-running access because the gateway is no longer in the request path.
Common Variations and Edge Cases
Tighter gateway control often increases latency and implementation overhead, so organisations must balance stronger revocation and auditability against developer friction and runtime complexity. There is no universal standard for this yet, especially for multi-agent systems where one agent may call another and each hop needs a clear trust decision.
One common edge case is toolchains that cache tokens locally for performance. That can quietly turn a gateway-managed model into an agent-held one if the cache survives longer than intended. Another is browser-embedded or desktop agents, where the runtime boundary is weaker and secret extraction is easier. In those environments, the safer pattern is often workload identity plus per-request token exchange rather than a durable credential in the agent.
NHIMG’s Guide to the Secret Sprawl Challenge is relevant here because sprawl often starts with convenience exceptions that become permanent. The same issue is highlighted in the OWASP Agentic AI Top 10, which treats uncontrolled tool access and secret exposure as core agent risks.
For high-risk workloads, the safer design is usually gateway-managed by default, agent-held only when there is a strong functional need, and every exception time-bounded and reviewed. That approach is easiest to defend when the agent’s behaviour is unpredictable and the environment cannot guarantee clean isolation.
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 CSA MAESTRO define the specific risk controls and attack patterns relevant to this topic.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Non-Human Identity Top 10 | NHI-03 | Addresses secret rotation and exposure risk for non-human identities. |
| OWASP Agentic AI Top 10 | A-02 | Covers agent tool and credential abuse risks in autonomous workflows. |
| CSA MAESTRO | Relevant to runtime trust decisions and agentic threat modeling. |
Keep secrets short-lived, rotate them automatically, and remove them from agent runtimes.
Related resources from NHI Mgmt Group
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Reviewed and updated by the NHIMG editorial team on June 23, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
