Execution rounds: pitfalls

Wrong forms, silent outcomes, LDC-E diagnostics, typical mistakes of formalizers and AI agents, how to detect them. Items marked “confirmed by run” were reproduced during this research on the installed engine.

OverviewBoundariesCorpus formsPitfalls

1. Reading the next round (confirmed by scenario, statics by code)

A round-r rule reading a higher-rank round atom (counter(i + 1) in the body with a round-i head) is rejected with LDC-E4120 STAGE_CYCLE_WITHOUT_DESCENT / NON_EXECUTABLE_UNSTRATIFIED — even outside a cycle and even with a positive cycle shift sum. Reason: the future round’s atom does not exist yet in round r — not_known over it is true and not retracted, while a positive read would write into a finished round. Detection: every read’s shift counts from head to read; a negative shift is a refusal with the rule address, ahead of producer checks. AI agents often “peek” into the next round for the minimum/total — a round total is read only from the next round (a + 1 shift on the reader), never the reverse.

2. Head without a bound index

A round rule whose index argument is bound by neither a domain literal, nor a round-predicate read, nor a + 1 shift from such a read is LDC-E4121 STAGE_UNBOUND_PRODUCER / NON_EXECUTABLE_STAGE_PRODUCER: a producer without an index has no round to execute in. Order matters: next-round reads (item 1) check before producers — a rule reading a future round gets the cycle refusal, not the producer refusal, even when its index is bound only by an outside-round read. Detection: every round head must show one of the three item-2 generation ways.

3. Domain, step, grid

An empty domain (from > to under ascending), a step outside the add_calendar_period calendar units, to off the from + n·step grid, a nonexistent grid date (the 31st on a monthly step across February — without last_day_of_month, the declaration is rejected as with reject_nonexistent) — LDC-E4122 at the compiler, NON_EXECUTABLE_STAGE with a reason at the evaluator. Integer has no step; Date requires one. AI agents love “round” boundaries (a quarter-end to off-grid) — the grid counts from from, not from the calendar.

4. Binds: type, position, overlap

A parameter at a bind position must have the index type — otherwise LDC-E4123 STAGE_BINDING_TYPE. One predicate in two stage, a second executable stage with overlapping binds, a round rule reading another stage’s round predicate — LDC-E4124 / NON_EXECUTABLE_STAGE_MULTIPLE / NON_EXECUTABLE_UNSTRATIFIED. Detection: a “predicate → stage” table over all bind; an overlap is a pre-conclusion refusal. Allowed neighbourhood (disjoint) — the navier-stokes/poincare specimen (see corpus-forms.md, items 5–6).

5. Closure and procedure next to stage

Closure over a round predicate (and over an upper rule’s conclusion) — LDC-E4125 STAGE_CLOSURE_UNSUPPORTED / NON_EXECUTABLE_STAGE_CLOSURE: a named boundary, not a default. A procedure in a program with an executable stage — LDC-E4126 STAGE_PROCEDURE_UNSUPPORTED / NON_EXECUTABLE_STAGE_PROCEDURE: the fold over rounds is undefined. The bypass specimen — the renovation schedule package: the procedure lives in the neighbouring package, the bridge is a plan (corpus-forms.md, item 3). Detection by statics; no silent behaviour here, both refusals loud and pre-conclusion.

6. Nonmonotone read with an underived shift

Statics derive a shift only when head and read indices are both domain literals or the same variable with an item-2 shift; a literal vs another’s variable, two different variables, or another shift-term form give no shift. A nonmonotone edge (completion, status, default, defeasible, priority — everything but monotone(P)/supported(P)) without a derived shift is rejected as a next-round read (LDC-E4120 / NON_EXECUTABLE_UNSTRATIFIED), regardless of cycle: an instance of such an edge is any rank pair, including a higher-rank read, and not_known over a missing atom is true and not retracted. A monotone edge with an underived shift is allowed (zero in the cycle sum), but publishing the head into a finished round at execution is fatal STAGE_LATE_WRITE. The AI-agent trap: an i == 2-shaped guard next to a variable read gives no shift — shifts derive from terms, not guards.

7. Empty body — a loud reserve (confirmed by run)

stage Empty {} is a legal form (status: "reserved") but executes in no version: evaluation stops before any conclusion with fatal NON_EXECUTABLE_STAGE, empty results and proofGraph.roots. Reproduction during this research (a scratch copy of the teaching package, installed law): law engine check — check OK, law test — “execution refused: NON_EXECUTABLE_STAGE”. The reverse would be the mistake: keeping a reserve in a live package “for the future” and waiting for a conclusion. A text finding: the binary message says “introduced only in 0.3” — stale wording (rounds run under the current 0.2 revision), the refusal itself holds.

8. Silent outcomes that read as mistakes (but are not)

• An empty round is not a refusal: a round with not one application counts towards maxStages, execution runs to to: domain 1…3 with maxStages = 2 gives RESOURCE_LIMIT, not a round skip.
• NEITHER on a missing start is the norm: an unstarted counter stays silent (the no-seed scenario test), while the document stays complete.
• An application with a rank above current is not published now and is reconsidered in its own round — neither loss nor double.
• An explicit tail of the former revision in the query (0.2.0…0.2.3) with an executable body gives the former NON_EXECUTABLE_STAGE: fixed not by editing the body but by the family name (0.2) or the 0.2.4 revision.