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Testing Every Engine Slot Against Known-Wrong Inputs Before Promotion

Why positive unit tests are not enough: every AgentFoundry conformance kit pairs known-good fixtures with known-wrong controls and keyword-matched benign twins.


A common failure in AI-generated test suites is the vacuous pass: a test or verifier function that checks only whether an output object exists (assert result is not None) without testing whether broken or unsafe outputs are actually rejected. On getagentfoundry.si, no component pack or engine adapter can be promoted unless its verifier.py passes a three-part conformance kit:

# Conformance Kit Meta-Test: Proving the Verifier Rejects Known-Wrong Controls
def qualify_slot_verifier(verifier_fn, kit: dict) -> dict:
    for good in kit["known_good"]:
        res = verifier_fn(good["candidate"])
        if res["status"] != "passed":
            return {"qualified": False, "reason": f"rejected_known_good:{good['id']}"}

    for wrong in kit["known_wrong"]:
        res = verifier_fn(wrong["corrupted_candidate"])
        if res["status"] == "passed":
            return {"qualified": False, "reason": f"vacuous_verifier_accepted_known_wrong:{wrong['id']}"}
        if res.get("refusal_code") != wrong["expected_refusal_code"]:
            return {"qualified": False, "reason": f"wrong_refusal_code:{res.get('refusal_code')}"}

    return {"qualified": True, "good_checked": len(kit["known_good"]), "wrong_rejected": len(kit["known_wrong"])}

When one of our early skill cards caused a -0.149 score regression on glm-5.3-flash, adding known-wrong controls and non-regression gates caught the failure immediately and blocked promotion until the card beat the unassisted baseline.


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