An AI agent holding a valid credential and using an approved tool looks legitimate to identity and endpoint controls, because at those layers it is. Detecting that it acted outside its scope requires evaluating the change it made against what it was authorized to change, which is a different question from whether the actor was authenticated.
Why this is hard
Security tooling is largely organized around two questions: is this actor who they claim to be, and does this activity match a known attack pattern. An agent with valid credentials passes the first. An agent using approved tooling to make a damaging change frequently passes the second, because in isolation the action is not malicious.
The result is a class of incident where every control worked as designed and the damage happened anyway. Nothing was compromised. The agent did what it was told, and what it was told was wrong.
The three ways this actually happens
- Bad instruction. A prompt, a chained instruction, or an injected input causes the agent to take an action the operator did not intend. The credential was legitimate and so was the tool.
- Scope creep in execution. The agent completes its task and takes additional actions it inferred were helpful. This is the most common and the least reported, because it usually does no damage and nobody looks.
- Adaptive routing. An agent that has one action blocked tries a different path to the same outcome. Controls that evaluate single actions in isolation see a series of unrelated attempts rather than a trajectory.
What to put in place
Evaluate the action, not the actor. Identity answers who. Something has to answer whether this specific change was authorized. If nothing in your stack asks that question, a valid credential is an unconditional grant.
Evaluate sequences, not just actions. Adaptive routing is invisible to per-action controls by construction. Watching the sequence of changes against the declared scope is what surfaces an agent working toward an outcome it was not authorized to reach.
Check state after the task, not just during it. Comparing system state against declared intent after an agent finishes catches drift that no individual action triggered. This is cheap and almost nobody does it.
Record everything, including what was allowed. A record of blocked actions tells you what the agent tried. A record of allowed actions tells you what it did. The second is what you need when someone asks what happened.
What this looks like in practice
Mimic’s AI Shield binds an agent’s declared scope before it acts and blocks actions outside that scope at the kernel, regardless of credential validity. Trajectory interception evaluates change sequences rather than individual actions, and post-task drift detection compares resulting system state against declared intent.
The general principle matters more than any product. Once an agent holds a valid credential, the only remaining question your stack can usefully ask is whether the change it just attempted was in scope. That question is the center of agentic AI security.
Valid credentials, answered.
Can identity and access management solve this?
+Identity controls verify the actor and limit what the actor can reach. They do not evaluate whether a specific change was authorized. An agent scoped correctly at the identity layer can still make an unauthorized change within the scope it was legitimately granted, and IAM has no view of that.
Will EDR catch an AI agent acting outside its scope?
+Usually not. Endpoint detection identifies activity matching known attack patterns. An agent with valid credentials using approved tooling produces activity that does not match a malicious pattern, because in isolation it is not malicious. The problem is authorization, not maliciousness.
What is trajectory interception?
+Evaluating a sequence of changes against declared scope rather than judging each change on its own. It matters because an adaptive agent that has one action blocked will attempt a different route to the same outcome, and per-action controls see unrelated attempts rather than a pattern moving toward an unauthorized result.
How do we know an agent exceeded its scope if nothing broke?
+You do not, unless something compared what the agent did against what it was authorized to do. This is the case for post-task state comparison. Most scope violations cause no visible failure, which is exactly why they go unreported until one of them does.
