Prompt Injection Defense Checklist

Turn prompt injection defense checklist into a testable buying decision

The useful question is not whether an agent sounds capable. It is whether a specific released version can produce the required outcome for Prompt Injection Defense under the data, tools, latency, cost, security, and review constraints that will exist in production. This guide focuses on how to review concrete checks before production deployment.

Write the task contract before comparing products: define representative inputs, acceptable outputs, unacceptable failures, required integrations, data sensitivity, budget, latency target, tool permissions, escalation rules, and the points where a person must approve an action. That prevents a polished demo from silently becoming the evaluation standard.

Plan around the risk before giving the agent more authority

A central risk for this decision is untrusted content manipulating tool-using agents. Reduce that risk with least-privilege access, explicit read/write boundaries, representative tests, observable execution, human escalation, and a rollback path. Unknown evidence should remain unknown; it should never be converted into a passing control because no failure has been observed yet.

Security and reliability belong in the same decision. An agent that is accurate when it succeeds can still be a poor production choice if failures are silent, retries duplicate actions, credentials are too broad, or a human cannot reconstruct what happened.

Use a five-stage evidence gate

1. Define success. Choose representative tasks, measurable pass conditions, difficult cases, and expected failure states.

2. Apply hard constraints first. Remove agents that cannot meet mandatory data, integration, deployment, permission, latency, support, or budget requirements before comparing aggregate scores.

3. Inspect the evidence. Check the tested version, observation count, available tools, failure accounting, confidence, and whether the evidence still matches the current release.

4. Pilot with minimum authority. Begin read-only where possible, require approval for consequential actions, keep logs, define stop conditions, make rollback straightforward, and measure cost per successful outcome.

5. Re-evaluate after change. Models, prompts, tools, permissions, routing, or integrations can materially change behavior. Bind production approval to the tested release.

Require concrete answers before deployment

• What failure is this control designed to prevent?
• What evidence demonstrates the control works?
• Who owns approval and exceptions?
• How is the control re-tested after a release change?
• What happens when the control fails?