Duty: addressee, goal, window

For LLMs8 sections

Updated 3 October 2026: concept, except_when, claim, definition … sufficient, and default strength have been removed, together with their special deprecation diagnostic. References below to the former behavior and corpus sources are historical. New source uses relation, unless, duty, a strict rule, and defeasible.

1. What it is in one sentence

duty is a normative position that requires of its addressee that something be achieved, maintained, or not done within a given window: the author reaches for it when the source says “is obliged to”, “must”, “ensures”.

A duty always names who owes it, what is owed, and by when: one addressee, one goal, one performance window.

2. When to take it and when not to

Instead	Take when	Selection rule
`prohibition`	the source says “is prohibited”, “is not allowed”	write `prohibition`: it is a `duty` with a forbearance goal spelled the way the act speaks; do not duplicate it with a paired `maintenance` duty — you get two `VIOLATED` for one breach
`constraint`	a whole world must be rejected, not a person addressed	a `constraint` has neither an addressee nor a performance window; a duty always names its addressee
`rule strict` with an institutional head	a status is derived (“is deemed to have defaulted”), not behaviour required	a fact-head has no position lifecycle
`claim`	a claim “creditor against debtor” is to be recorded	avoid `claim`: write `duty` with the parties directly — the debtor in the `bearer` field, the creditor in the `beneficiary` field

Three goal kinds: achievement (achieve the condition inside the window), maintenance (hold the condition over the whole window), forbearance (not to perform the action in the window; almost always written as prohibition). A fourth kind, recurring every, is executable in 0.2 (E-0146); mandatory over gives the overall repetition interval.

Grammar: duty, goals, norm head (EBNF verbatim from the language grammar)

Show syntax reference

The duty form — the addressee (bearer), the beneficiary, and a single goal:

duty_conclusion         = "duty", [ identifier ], "{",
                            { duty_item },
                          "}" ;
duty_item               = "bearer", expression, ";"
                        | "beneficiary", expression, ";"
                        | "goal", goal, [ ";" ]
                        | compact_duty_goal
                        | "activation", formula, ";"
                        | "discharge_policy", reference, ";"
                        | "violation_policy", reference, ";"
                        | source_anchor_item
                        | metadata_item ;

The three base forms follow; recurring every <step> { … } over <interval> is executable in 0.2 (E-0146).

achievement_goal        = "achievement", "{",
                            "condition", formula, ";",
                            "window", interval_expression, ";",
                            { goal_item },
                          "}" ;
maintenance_goal        = "maintenance", "{",
                            "condition", formula, ";",
                            "window", interval_expression, ";",
                            { goal_item },
                          "}" ;
forbearance_goal        = "forbearance", "{",
                            "action", expression, ";",
                            "window", interval_expression, ";",
                            { goal_item },
                          "}" ;

The norm head — any modality with an optional template StableId annotation. A claim is written as duty with the parties directly — the debtor in the bearer field, the creditor in the beneficiary field:

norm_conclusion         = { annotation },
                          ( duty_conclusion
                          | liberty_conclusion
                          | power_conclusion
                          | immunity_conclusion
                          | prohibition_conclusion ) ;

Position statuses and lifecycle live on the lifecycle page; windows as intervals and their computation — on the deadline-calendar page; window syntax is not duplicated here.

3. Minimal example

Package examples/duty-achievement/: a supplier must deliver goods in March 2026. Full code — examples/duty-achievement/package.law; cases and expectations — examples/duty-achievement/tests/01-in-window.lawtest (scenarios in the window) and tests/02-after-window.lawtest (scenarios after the window).

rule DeliveryRule defeasible {
    for s: Supplier;
    for c: Customer;
    when contract_signed(s, c);
    then duty Deliver {
        bearer s;
        beneficiary c;
        goal achievement {
            condition goods_delivered(s, c);
            window [@2026-03-01, @2026-03-31];
        }
    };
}

Case facts: contract_signed(alpha, omega). Query positions().

The engine’s actual answer (see How the engine answers):

legal_time @2026-03-15, no delivery → position(Deliver, ACTIVE), not VIOLATED (before the deadline an unperformed duty is active);
same date + goods_delivered → position(Deliver, SATISFIED);
legal_time @2026-04-10, with no facts of non-performance → position(Deliver, UNDETERMINED), not VIOLATED (absence of proof of performance is not a breach);
same date + not goods_delivered → position(Deliver, VIOLATED).

Sensitivity check: remove contract_signed from the case — position Deliver is never created (no body substitution); remove goods_delivered from the second scenario — the answer changes from SATISFIED to ACTIVE. The example is not vacuous.

4. Example across domains

The same “duty with a window” device in different domains:

Law: the duty to insure cargo — examples/duty-maintenance/ (KeepInsured, maintenance with a March window; the counterexample not goods_insured gives VIOLATED immediately).
Law: the ban on subcontracting — the same package (NoSubcontracting; prohibition reads as a duty with a forbearance goal; the fact subcontracts in the window gives one VIOLATED).
Standard/protocol: the duty to keep a unit ready (package us.army.training — US Army training norms, UnitTrainingReadiness — military training in the same duty form outside civil law).
Religion/ethics: the duty to respect all religions (package mng.corpus.yasa — the Mongol Yasa, RespectAllReligions — the same construct for an ethical norm).
Custom/casework: court duties in banking disputes (package kz.corpus.np_bank_loan_disputes — Kazakh banking-dispute casework — five duties with a [den, infinity) window).

Forms in detail — corpus-forms.md.

5. How the engine answers

Run output (verbatim):

check OK: docs/research/constructs/10-duty/examples/duty-achievement
law test research.constructs.duty_achievement: мир research.constructs.duty_achievement
  ok   [research.constructs.duty_achievement#authored] tests/01-in-window.lawtest / in window without delivery — ACTIVE not VIOLATED
  ok   [research.constructs.duty_achievement#authored] tests/01-in-window.lawtest / delivery inside window — SATISFIED
  ok   [research.constructs.duty_achievement#authored] tests/02-after-window.lawtest / after window without explicit non-performance — UNDETERMINED
  ok   [research.constructs.duty_achievement#authored] tests/02-after-window.lawtest / after window with established non-performance — VIOLATED
итого: 4 проверено, 4 прошли, 0 не прошли, 0 не исполнены; код 0

check OK: docs/research/constructs/10-duty/examples/duty-maintenance
law test research.constructs.duty_maintenance: мир research.constructs.duty_maintenance
  ok   [research.constructs.duty_maintenance#authored] tests/01-violations.lawtest / counterexample inside window violates maintenance
  ok   [research.constructs.duty_maintenance#authored] tests/01-violations.lawtest / established action inside window violates prohibition once
  ok   [research.constructs.duty_maintenance#authored] tests/02-excuse.lawtest / force majeure defeats the excusable duty
  ok   [research.constructs.duty_maintenance#authored] tests/02-excuse.lawtest / without force majeure the duty stays active
итого: 4 проверено, 4 прошли, 0 не прошли, 0 не исполнены; код 0

Position statuses: PENDING (before the window), ACTIVE (in the window, unperformed), SATISFIED, VIOLATED, UNDETERMINED, DEFEATED (defeated by a defeater — status literals are not published), EXPIRED/CREATED for liberties. Observation in a test — position(Name, STATUS); the normative_status aggregate over several norms answers UNDETERMINED. In proof — the support of the applying rule and the support of the goal condition; why_not names the unestablished conjunct.

A window from case variables (tests “case window: ACTIVE before the deadline” and “case window: VIOLATED after the deadline with non-payment”):

Facts	Question	Answer	Why
`invoice_issued(…, 5 March, 15 March)`	`Pay` with decision on 10 March	`ACTIVE`	window from rule variables, deadline not passed
same + `not paid`	`Pay` with decision on 20 March	`VIOLATED`	window closed, non-performance established

6. Common mistakes

The goal condition repeats the rule body — the duty is always SATISFIED (tautological goal; warning LDC-E1371).
Two goals in one duty — rejection LDC-E0201.
A prohibition + a paired maintenance duty — two VIOLATED for one breach.
A bare name as a window bound — rejection LDC-E2115; write a date, a body variable, or the open floor [@0001-01-01, infinity).
unless on a norm-head binds not all payload variables — rejection LDC-E4101 on node <Rule>/unless/N.
Rule name coincides with position name — LDC-E1338.
condition with _ — check stays silent, execution never finds the literal (a known open gap; see pitfalls.md).

Each analysed — pitfalls.md.

7. References

The language specification defines positions, goals, neighbouring forms, the lifecycle, defeat, the positions query, and test observations; this page states how to use them.
Tutorials: /tutorials/writing-tests/ (test observations), /tutorials/defeaters/ (defeater versus priority).
Details: corpus-forms.md, pitfalls.md, boundaries.md.

Documentation for Arxo. Writings — blog.arxo.io.

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