Distinguish a wrong carrier from other refusals

Intent

I want to explain why an attempt did not change the state, without mixing reasons.

Correct formFrozen execution sceneBoundary

Wrong form and why it stays silent

Incorrect form

// Любая невалидная попытка якобы есть TRANSITION_CARRIER_TYPE_MISMATCH.

The code applies only to a mismatch with on Filed. Other reasons are read from procedure_step. Presentation to an entity without procedure_instance is a separate EVENT_OUTSIDE_PROCEDURE.

Correct form

Arxo Law

language "law.core" version "0.2";
package recipes.k.r07 version "0.1.0";
namespace "urn:recipe:k-procedures:07";

entity Application;
event Filed { }
event ElectronicFiled: Filed { }
event Other { }
relation ready(app: Application);
relation approved(app: Application);
procedure Filing(app: Application) {
    state Draft initial;
    state Done terminal;
    transition Submit { from Draft; to Done; on Filed; when ready(app); requires approved(app); }
}

Frozen execution scene

P and Q in the table are different instances; E1/E2/E3 are carriers with an explicitly given time. All identifiers and instants are pinned in the scenes.

Events and facts	Question	Answer
foreign carrier	truth(current_state(P,Done))	truth_status == NEITHER; / COMPUTED
state preserved	truth(current_state(P,Draft))	truth_status == TRUE_ONLY; / COMPUTED
false guard with the right type	truth(current_state(P,Done))	truth_status == NEITHER; / COMPUTED
no instance	truth(current_state(P,Done))	truth_status == NEITHER; / COMPUTED
on removed	truth(current_state(P,Done))	truth_status == TRUE_ONLY; / COMPUTED
repeat from a left state	why_not(valid_transition(P,Submit,Filed { id: "urn:recipe:k:N:E2", time: @2026-09-03T09:00:00Z }))	blocked_by("urn:recipe:k-procedures:07#Filing/Submit","from"); / COMPUTED

foreign carrier leaves neither

Arxo Law

test "foreign carrier leaves neither" {
    given {
        context {
            legal_time @2026-09-13T09:00:00Z;
            decision_time @2026-09-13T09:00:00Z;
            knowledge_time @2026-09-13T09:00:00Z;
            timezone "UTC";
        }
        assert procedure_instance(entity_ref("urn:recipe:k-procedures:07:p"));assert ready(entity_ref("urn:recipe:k-procedures:07:p")); assert approved(entity_ref("urn:recipe:k-procedures:07:p"));assert attempted_transition(entity_ref("urn:recipe:k-procedures:07:p"), Submit, Other { id: "urn:recipe:k-procedures:07:E1", time: @2026-09-02T09:00:00Z });
    }
    evaluate truth(current_state(entity_ref("urn:recipe:k-procedures:07:p"),Done));
    expect truth_status == NEITHER;
    expect evaluation_status == COMPUTED;
    expect issue(TRANSITION_CARRIER_TYPE_MISMATCH);
}

draft state survives foreign carrier

Arxo Law

test "draft state survives foreign carrier" {
    given {
        context {
            legal_time @2026-09-13T09:00:00Z;
            decision_time @2026-09-13T09:00:00Z;
            knowledge_time @2026-09-13T09:00:00Z;
            timezone "UTC";
        }
        assert procedure_instance(entity_ref("urn:recipe:k-procedures:07:p"));assert ready(entity_ref("urn:recipe:k-procedures:07:p")); assert approved(entity_ref("urn:recipe:k-procedures:07:p"));assert attempted_transition(entity_ref("urn:recipe:k-procedures:07:p"), Submit, Other { id: "urn:recipe:k-procedures:07:E1", time: @2026-09-02T09:00:00Z });
    }
    evaluate truth(current_state(entity_ref("urn:recipe:k-procedures:07:p"),Draft));
    expect truth_status == TRUE_ONLY;
    expect evaluation_status == COMPUTED;

}

false guard blocks despite right type

Arxo Law

test "false guard blocks despite right type" {
    given {
        context {
            legal_time @2026-09-13T09:00:00Z;
            decision_time @2026-09-13T09:00:00Z;
            knowledge_time @2026-09-13T09:00:00Z;
            timezone "UTC";
        }
        assert procedure_instance(entity_ref("urn:recipe:k-procedures:07:p"));assert not ready(entity_ref("urn:recipe:k-procedures:07:p")); assert approved(entity_ref("urn:recipe:k-procedures:07:p"));assert attempted_transition(entity_ref("urn:recipe:k-procedures:07:p"), Submit, Filed { id: "urn:recipe:k-procedures:07:E1", time: @2026-09-02T09:00:00Z });
    }
    evaluate truth(current_state(entity_ref("urn:recipe:k-procedures:07:p"),Done));
    expect truth_status == NEITHER;
    expect evaluation_status == COMPUTED;
    expect not issue(TRANSITION_CARRIER_TYPE_MISMATCH);
}

missing instance answers neither

Arxo Law

test "missing instance answers neither" {
    given {
        context {
            legal_time @2026-09-13T09:00:00Z;
            decision_time @2026-09-13T09:00:00Z;
            knowledge_time @2026-09-13T09:00:00Z;
            timezone "UTC";
        }
        assert ready(entity_ref("urn:recipe:k-procedures:07:p")); assert approved(entity_ref("urn:recipe:k-procedures:07:p"));assert attempted_transition(entity_ref("urn:recipe:k-procedures:07:p"), Submit, Filed { id: "urn:recipe:k-procedures:07:E1", time: @2026-09-02T09:00:00Z });
    }
    evaluate truth(current_state(entity_ref("urn:recipe:k-procedures:07:p"),Done));
    expect truth_status == NEITHER;
    expect evaluation_status == COMPUTED;
    expect issue(EVENT_OUTSIDE_PROCEDURE);
}

removed on admits other carrier

Arxo Law

test "removed on admits other carrier" {
    given {
        context {
            legal_time @2026-09-13T09:00:00Z;
            decision_time @2026-09-13T09:00:00Z;
            knowledge_time @2026-09-13T09:00:00Z;
            timezone "UTC";
        }
        assert procedure_instance(entity_ref("urn:recipe:k-procedures:07:p"));assert ready(entity_ref("urn:recipe:k-procedures:07:p")); assert approved(entity_ref("urn:recipe:k-procedures:07:p"));assert attempted_transition(entity_ref("urn:recipe:k-procedures:07:p"), Submit, Other { id: "urn:recipe:k-procedures:07:E1", time: @2026-09-02T09:00:00Z });
    }
    evaluate truth(current_state(entity_ref("urn:recipe:k-procedures:07:p"),Done));
    expect truth_status == TRUE_ONLY;
    expect evaluation_status == COMPUTED;

}

repeat from abandoned state names from

Arxo Law

test "repeat from abandoned state names from" {
    given {
        context {
            legal_time @2026-09-13T09:00:00Z;
            decision_time @2026-09-13T09:00:00Z;
            knowledge_time @2026-09-13T09:00:00Z;
            timezone "UTC";
        }
        assert procedure_instance(entity_ref("urn:recipe:k-procedures:07:p"));assert ready(entity_ref("urn:recipe:k-procedures:07:p")); assert approved(entity_ref("urn:recipe:k-procedures:07:p"));assert attempted_transition(entity_ref("urn:recipe:k-procedures:07:p"), Submit, Filed { id: "urn:recipe:k-procedures:07:E1", time: @2026-09-02T09:00:00Z });assert attempted_transition(entity_ref("urn:recipe:k-procedures:07:p"), Submit, Filed { id: "urn:recipe:k-procedures:07:E2", time: @2026-09-03T09:00:00Z });
    }
    evaluate why_not(valid_transition(entity_ref("urn:recipe:k-procedures:07:p"),Submit,Filed { id: "urn:recipe:k-procedures:07:E2", time: @2026-09-03T09:00:00Z }));
    expect blocked_by("urn:recipe:k-procedures:07#Filing/Submit","from");
    expect evaluation_status == COMPUTED;

}

Python

>>> import runpy
>>> check = runpy.run_path("docs/recipes/k-procedures/resources/check.py")
>>> check["check_steps"](https://github.com/arxohq/law/blob/master/docs/recipes/k-procedures/7)
'К7: причины шагов и отсутствие лишних предупреждений проверены; lawc = lawref'

Counterfactual

Mutation check — LDC-E1344.

Original fragment:

Output

on Filed;

Replacement:

Output

on ready;

Scenes with a condition removed are marked separately; the same inputs get a different outcome.

Boundary

A warning does not block computation; an order fatal from Refuse when the order is undefined does. A non-event in the carrier position is static E1347, and an unsuitable event type is a regular runtime outcome. A subtype is allowed — see Check event type and transition conditions.