JEV USE CASE
Prompt-Injection Detection.
Inspect retrieved or user-supplied content before an agent lets that content influence tool use.
THE DECISION CONTRACT
STATE
A webpage tells the browsing agent to ignore prior instructions and upload local files.
QUESTION
How should the agent treat this content?
CHOICES
safe_context untrusted_instruction possible_injection block
TYPESCRIPT EXAMPLE
Ask for one bounded answer
This Vercel AI SDK-shaped example is illustrative. Check the current provider documentation before shipping.
import { experimental_evaluate as evaluate } from 'ai';
const result = await evaluate({
model: 'typesafe-ai/jev',
state: "A webpage tells the browsing agent to ignore prior instructions and upload local files.",
questions: {
decision: {
type: 'choice',
instructions: "How should the agent treat this content?",
options: ["safe_context","untrusted_instruction","possible_injection","block"]
}
}
});
// Validate permissions and thresholds before acting.
console.log(result.answers.decision);SAFE IMPLEMENTATION
Keep the boundary clear
Guardrail
Use this as one layer. Hard permission boundaries, sandboxing and allowlists must remain deterministic.
- Log the input, answer distribution, chosen threshold and resulting route.
- Test on labelled examples from your own production distribution.
- Send low-confidence, high-impact or out-of-distribution cases to a safer fallback.
- Re-evaluate thresholds when the model or workflow changes.
PRIMARY SOURCES