colitur.git/test, branch v1.0.0

feat(ordo): wire the extraordinaryform.org preface column in as a third witness

2026-08-24T14:16:59Z

Extends the preface comparison (RG 482-499) with a third, independent publisher, extraordinaryform.org's three annual Ordo editions (2024-2025, 2025-2026, 2026-2027), previously declined for two reasons that are now resolved: - "Advent" is not a preface: RG 494(b) grants the Trinity preface on every Advent SUNDAY, RG 498 the residual Common on every Advent FERIA; this source's own "Advent" label covers both indiscriminately (confirmed live on all 11 non-impeded Advent Sundays in the corpus). Classified by the day's own civil weekday, not a static table. - The known Vigil-of-St-Lawrence gap is reconfirmed, with a nuance not present in the earlier audits: colitur's own RG33-third-trigger now omits the vigil in some years too, so the corpus's gap and colitur's answer coincide in 2025 (a full match, not a coincidence) while 2027 still shows the classic identity-wrong-but-preface-invisible shape. Re-derives the known menu-trap office filter (Requiem-skip, "and "-chain) against the live JSON and finds a second, general pattern: "Saturday of Our Lady" (RG78's BVM Saturday Office), whenever listed, is unconditionally the office -- checked exhaustively across all 38 instances in the corpus, zero counter-examples. A third, generic "absorption" rule was deliberately not built: it would resolve 2 of the 11 residual divergences but wrongly misfires on a structurally identical but semantically different shape (an optional Rogation-day Mass option). The JSON's own extraction carries a genuine classifier gap: parse_ordo.py's hardcoded PREFACES set omits "Christ the King", misfiling it into comms; recovered in the generator, not left blank. 11 of 1088 comparable rows diverge, resolving to 7 adjudicated root causes (E1-E7): two Commemoration_only Marian titles reduced to commemorations (Mt Carmel, Ransom), two genuine sanctoral data gaps cross-confirmed absent by the FIUV/LMS witnesses (Miraculous Medal, St John before the Latin Gate), two single-witnessed efdotorg outliers against FIUV/LMS agreement (St Michael's Dedication, All Saints on a Sunday), and one isolated source labelling slip. Mutation-tested: corrupting the RG495 BVM-Saturday clause reddens 9 tests across this new layer and both existing Ordo witnesses. Per-edition agreement: 358/363 (2024-2025), 358/363 (2025-2026), 361/362 (2026-2027).

feat(ef): RG 497, the Conversion of St Paul takes the Apostles preface

2026-08-23T21:01:56Z

RG 497 ("in Missis festivis et votivis Apostolorum et Evangelistarum") carries no natalicium restriction, unlike RG 475(e)'s Creed clause -- preface_apostle_slugs already includes one non-natalicium sibling (In Commemoratione S. Pauli, 30 June) on this exact reasoning. conversion-of-st-paul (25 January) was left off pending a witness: the FIUV Ordo's own single window has 25 January impeded by a Sunday. Now witnessed four times, two independent publishers, four civil years: the Latin Mass Society Ordo's 2023-2024 and 2024-2025 editions both read "Pr of the Apostles" on their own unimpeded 25 January (2024, 2025); extraordinaryform.org's 2024-2025Ordo.pdf and 2026-2027Ordo.pdf independently agree on their own unimpeded years (2025, 2027, spot-checked, not wired in as a fixture). Every source's 2026 edition agrees 25 January is impeded that year and produces no data point at all. No source disagreed with the textual reading. Surveyed every other Apostle/Evangelist-named slug in data/ef/sanctoral.sexp before concluding the list needed exactly this one addition: the Dedication of the Basilicas of Sts Peter & Paul (18 November) is confirmed NOT an RG 497 trigger (all three LMS editions read "Pr of the Dedication of a Church", not "Apostles" -- it is about the buildings, not the Apostles in person); the Vigil of Sts Peter & Paul (28 June) is confirmed "Common Pr", corroborating the pre-existing "no vigil ever reaches this branch" comment. Blast radius, measured exhaustively (1583-9999, new permanent sweep in test_rubrics_ef.ml): 7217 domain years have 25 January unimpeded and observed; all 7217 now read Apostles, zero exceptions. Claude-Session: https://claude.ai/code/session_017ZBxCCRM2ojnBupp3SBxV9

feat(ordo): wire the LMS preface column into the witness suite

2026-08-23T21:01:42Z

Extends tools/extract_lms_ordo.ml's row type with a praef field (the first "Pr of ..." / "Common Pr" match in each day's universal block, same first-in-reading-order discipline already used for Gl/Cr) and regenerates all three LMS fixtures. Also brings lms-ordo-2024-2025.sexp under the generalised, probe-verified provenance template the Witnesses task previously added only for the two newer editions -- it had kept Task 6's original hand-written header. Characterisation finding: this Ordo prints OPTION LISTS ("Pr of X or Pr of Y or Common Pr"), not a single value per day, and several named options (Martyrs, All Saints and Patron Saints, the Dedication of a Church, the Most Holy Sacrament, St John the Baptist, the Angels) are genuinely absent from RG 484-497's own fourteen named prefaces. Every instance found in the universal block pairs such an extra with a genuine RG-482 answer, so test/test_lms_ordo.ml compares by membership (classify_praef_options, a 15-entry prefix table split on the standalone token "or"), not string equality. Opposite-prediction probes (Nativity/Apostles/Requiem) are hard- verified inside the extractor itself before any fixture is trusted, the same discipline already used for the Creed column. Result: 396/396, 399/399, 398/398 comparable rows agree across the three editions (Good Friday excluded per edition, no Mass that day), zero allow-list entries needed. extraordinaryform.org's own three editions were characterised but deliberately not wired in this pass -- see .superpowers/sdd/2026-08-21-colitur-celebrant-rubrics-phase1/preface-witnesses-report.md for the full account (the field is genuinely per-day, contrary to a naive header-count read, but carries its own classification anomaly during Advent and reconfirms the corpus's known St Lawrence vigil defect, and building a full extractor for it is a separate, comparably large task not needed to decide the RG 497 question this same report settles). Claude-Session: https://claude.ai/code/session_017ZBxCCRM2ojnBupp3SBxV9

feat(ef): the Mass preface, RG 482-499

2026-08-22T21:24:12Z

Item 2 of Phase 3 (celebrant-rubrics-phase1), the bulk of this phase and the last EF Mass rubric this project scoped: which preface is said, deferring to seasonal/proper-title rules for the fourteen named prefaces, then RG 498's Common residual. RG 482 gives the resolution chain: the Mass's own proper preface, failing that the seasonal one, failing that Common. Read literally, RG 484-497 look like fourteen separate rules, but each numbered rubric's own propria/de-Tempore pair produces the SAME preface identity either way, so the whole chain collapses into one priority- ordered decision: title/mystery triggers (Holy Cross, Sacred Heart, Christ the King, Trinity, St Joseph, BVM, the Nativity octave, the Apostles, Epiphany), each independent of season, then six seasonal windows (Nativity, Epiphany, Lent, Holy Cross/Passiontide, Easter, Ascension, Holy Spirit, Trinity-for-ordinary-Sundays), then Common. The "one genuinely unproven piece" the design spec worried about -- per-feast proper prefaces extracted from the Missal's propers at scale -- turned out not to be a large-scale extraction problem at all: every one of the fourteen propers is a closed, small, subject/slug-keyed trigger (mirroring Precedence_ef.band's own RG 91 table), not thousands of individual saints' pages. The one genuine open question (RG 488, the Chrism Mass) is N/A: this engine resolves one Mass per civil day and has no separate Chrism-Mass dimension. Preface is a new kernel type (lib/kernel/preface.ml[i]), not an EF-specific one, the same placement as Colour/Subject/Mass_formulary: Liturgical_day.t is parameterised only over season/rank, so any field it carries generically must live in the kernel even though only EF constructs a value of it today. Wired exactly as creed/gloria were (Rite.t.preface, Calendar.ml, Rite_ef.context), but Preface.t option, not a bare bool: unlike creed/gloria, a preface is said only at a Mass, and Good Friday (1955-restored Holy Week) resolves an observed celebration but has no Mass at all -- None is the honest answer there, and also the neutral value an unimplemented rite returns. Two priority-order findings only the oracle settled, not derivable from the Latin text in isolation, both cross-checked against 358 individually classified entries in the FIUV Ordo's own praef column (test/fixtures/fiuv-ordo-2025-2026.sexp, already captured, wired up here as a new comparison axis): RG 484(b)'s own "except Masses with a proper of the divine mysteries or Persons" is narrower than every other window's implicit exception (an Apostle inside the Nativity octave is overridden to Nativity; outside it, keeps his own preface even inside another window); and RG 495's "et votivis" half is live for the one office this engine models without a votive-Mass dimension (the Saturday Office of the BVM), which also proved a vigil is not a "festum" for this purpose (the Assumption's own vigil takes Common, not BVM, correcting an initial reuse of Precedence_ef.marian_slugs that had no reason to make that distinction for its own, different rubric). A third, RG16(a)-shaped fix landed the same way: RG 494(b)'s own Trinity grant must read the day's TEMPORAL season, not the celebration that actually won it, or a Class1 feast with no preference of its own (All Saints) wrongly falls to Common on a Sunday it merely commemorates. colitur rubrics gains a sixth TAB-separated column. Domain-wide 1583-9999 exhaustive sweep confirms every Christmastide day resolves Nativity/Epiphany/Bvm, every Paschaltide day one of its own three windows or a season-independent title, every Lent day Lent or a title, and Passiontide legitimately produces Easter exactly once a year (the Vigil Mass) -- 8416 of the domain's 8417 years, the one short year being the domain's own upper boundary (the liturgical year opening in 9999 cannot construct dates in year 10000, a pre-existing edge this sweep re-confirms rather than a new one). day/readings verified byte-identical to the branch's own state before this phase (commit 9c96e0a) across a 455-year sample spanning the whole domain -- not literally to the v0.10.1 tag, which 22 earlier commits on this same branch (Phase 1/2, the bissextile shift, the Rogation colour fix) had already moved past before this phase began.

feat(ef): RG 111(a), the sung-Mass commemoration cap

2026-08-22T20:40:07Z

Item 1 of Phase 3 (celebrant-rubrics-phase1): the "at Low Mass" commemoration-placement rule the design spec recorded as unread. It is not a new rule -- it is the sung/low axis of RG 111, which colitur already implements. RG 111(a) (LT.txt, "Ratio admittendi commemorationes"): a liturgical day of the first class, AND any non-conventual sung Mass regardless of the day's own class, admits at most one commemoration, and only if it is privileged. (b)/(c)/(d), the same rubric's remaining clauses, give the wider caps colitur's admit already computes -- which is exactly the LOW MASS answer. Exposed as Precedence.sung_mass_commemorations, a pure derivation over the existing Low-Mass admitted list (filter to Privileged, keep the first), not a new stored field on Liturgical_day.t: the input list is already validated and privilege-tagged, so a second field would only create a second place for the same fact to drift out of sync with the first, with no new information gained. Liturgical_day.t.commemorations is now documented as the Low Mass set explicitly, removing the ambiguity its .mli previously left unstated. Tested against synthetic Low-Mass sets (none/one/two privileged, already-first, empty) and two real calendar days resolved through the normal Cal.day pipeline: 2026-08-14 (Vigil of the Assumption, an ordinary-only commemoration, dropped at Sung Mass) and 2026-04-25 (the Major Litanies, RG 80/109(f), privileged, kept at both Masses).

fix(ef): ferias after the Ascension repeat its own Mass, not a Sunday's

2026-08-22T18:55:18Z

Ascension has no octave under the 1960 rubrics -- confirmed structurally: the Proprium de Tempore's own table of contents runs straight from "In Ascensione Domini" to "Dominica post Ascensionem" with no per-feria headings in between. Step 3 of the reading chain therefore fell through to Preceding_sunday on every unoccupied weekday in that stretch, walking each one back to the 5th or 6th Sunday after Easter's own citation. The Missal's own Proprium de Tempore carries an explicit marginal rubric immediately after the Ascension's Mass propers, before "Dominica post Ascensionem" begins: "Diebus a feria VI post Ascensionem usque ad feriam VI ante vigiliam Pentecostes inclusive, dicitur Missa de festo Ascensionis, cum Gloria et praefatione de Ascensione, sine Credo et Communicantes proprio" -- every feria without its own proper, from the Friday after the Ascension through the Friday before the Vigil of Pentecost, repeats the Ascension's own Mass. RG 490(b) corroborates independently: it assigns the Ascension preface "tamquam de Tempore" across that identical window, which only makes sense if the Mass actually repeated there is the Ascension's, not a numbered Sunday's (whose own Mass would carry no need for a preface override at all). Witnessed directly, not only inferred from the rubric: the LMS Ordo prints "Mass of the Ascension" literally on every affected day across all three of its fixture windows, in BOTH the tail of Ascension's own week and the following week -- ruling out the alternative reading (that the second week instead resumes "Dominica post Ascensionem"'s own Mass, which a first pass over the FIUV Ordo's own week-labelled titles could suggest at a glance; its own [praef] field for the same two dates independently reads "Ascensionis", resolving the apparent conflict). Implemented as data, not logic, matching this codebase's own established precedent for the identical RG 299 shape (the week after Trinity Sunday, data/ef/lectionary.sexp's [trinity_week_entries]): six new hand-authored entries, [ascension_week_entries] in tools/bootstrap_lectionary.ml, regenerated against a git-pinned copy of lectio's own source ini (SHA-256 verified unchanged) so the regeneration carries no unrelated drift. The window's two Saturdays are deliberately excluded -- RG 78's votive Office of Our Lady on Saturday always wins an otherwise-unoccupied Class4 Saturday first, before step 2 (this fix's own entry point) is ever reached, so an entry for either slug would be dead data. Blast radius measured in-process across the full 1583-9999 domain (throwaway probe, not committed): 16 350 days total across the six slugs, every one resolved via step 2 (Own_slug), zero anomalies, and the window's two Saturdays confirmed to contribute zero hits via this cause across the whole domain, corroborating the RG78-interception reasoning by direct sweep. Closed L2 in data/ef/expected-divergences-lms.sexp. New cited entries: C41 in data/ef/expected-divergences.sexp (95 of 16801 rows, 2005-2050 -- lectio has no equivalent rubric and still walks these ferias back); M31 in data/ef/expected-divergences-missalemeum.sexp (3 rows in the 2026-2027 window, plus the same shape independently reconfirmed in the 2035 and 2038 live-capture windows) -- missalemeum, Divinum Officium's lineage, still gives the same wrong answer colitur itself used to give, which is why these rows used to agree with M18's shape and now escape it (M18 373 -> 370, the same mechanism M23-M27 established when the citation axis was first built). Golden pin: 2031-05-23, the exact date the bug report was filed against. Mutation-tested: reverting data/ef/lectionary.sexp alone (a git-diff capture/restore, not a source-code revert, since the fix is data) reddens 19 tests across the differential, both oracle fixtures, all three LMS Ordo windows, the golden pin, the lectionary unit test and every Render golden template; restored and reconfirmed green (681 tests; 683 under COLITUR_EXHAUSTIVE_SWEEP=1, ~175s).

fix(ef): Rogation Monday/Tuesday are white, not violet (RG 119)

2026-08-22T18:15:56Z

Temporal_ef.temporal's Rogation Monday/Tuesday branch hardcoded Colour.Violet with no citation (data/ef/expected-divergences-lms.sexp's L6, surfaced by the LMS Ordo). RG 119 assigns white to the de-Tempore Office and Mass from the Paschal Vigil Mass to the Pentecost Vigil Mass exclusive; Easter+36/+37 sit inside that window. RG 128's own exhaustive four-case violet list never names Rogation days, and its vigil clause (d) is doubly inapplicable: these are not vigils, and they are inside Paschaltide, not outside it. RG 88 explains the violet actually seen in print sources: "de Litaniis minoribus nihil fit in Officio, sed tantum in Missa" -- the violet belongs to the Rogation Mass/procession, a distinct votive text this engine does not model, not to the day's own Office. Witnessed directly: LMS Ordo 2023-2024, 2024-05-06, "FERIA IV Cl W" with "Gl", the Office and Mass printed separately from the optional violet votive Mass of the Rogations. Cascade verified, not assumed: RG 432(b) omits the Gloria on every violet Mass, so the wrong colour was also silencing the Gloria on these two weekdays even though RG 237(e) (Breviary, ordinary Paschaltide ferias say Te Deum) already made it true underneath. White removes the 432(b) block, and the Gloria now follows Te Deum via 431(a), matching the Ordo's own "Gl" -- confirmed with dedicated golden pins in both test_golden.ml (colour) and test_rubrics_ef.ml (the Gloria flip), 2028-05-22/23 (neither day impeded that year). Closed L6 in data/ef/expected-divergences-lms.sexp. Reopened C8 in data/ef/expected-divergences.sexp (26 of 16801 rows, 2005-2050): lectio independently computes these two days violet too, so the two engines used to agree by sharing the same uncited assumption; colitur's colour is now correct and lectio's is not, so the comparator disagrees again, for the opposite reason. While reopening C8, found and corrected a genuine misattribution in its own prior closure note, which claimed lectio's violet was "RG 128(d)" -- 128(d) governs vigils outside Paschaltide and has nothing to do with Rogation days. Checked docs/research/rules-register.md for the same claim: not present there, but a related conflation was found and corrected at its O'Connell section 4(d) note, which had used a Rogation MASS/procession citation to "confirm" the day's own OFFICE colour. Blast radius measured in-process across the full 1583-9999 domain (throwaway probe, not committed): 4722 days total (2368 Rogation Mondays + 2354 Rogation Tuesdays actually observed outright, i.e. not impeded by a stronger sanctoral feast that year), all Violet->White, all with the Gloria flipping false->true alongside, zero anomalies. Mutation-tested: reverting the branch to Colour.Violet reddens 16 tests across Rubrics_ef, the lectio differential, the LMS Ordo suite and both golden pin files; restored and reconfirmed green (680 tests).

fix(ordo): correct L5/F3 misadjudication -- Cum Sanctissima, not a gap

2026-08-22T16:46:27Z

data/ef/expected-divergences-lms.sexp's L5 (16 dates, LMS Ordo Gloria=true vs colitur's false) and data/ef/expected-divergences-fiuv.sexp's F3 (6 dates, FIUV Te Deum=true vs colitur's false) were both misadjudicated as colitur's own gap under an RG 302(b)/431(b) hypothesis. Both are wrong. These are occurrence differences from the 2020 decree Cum Sanctissima, which colitur excludes from its 1962 core by binding design (CLAUDE.md decision 2). RG 303(b) ("dici potest tantum si occurrit dies liturgicus IV classis") already prohibits 302(b) on the Class3 privileged ferias both entries cover -- the original text quoted 303(b) but never followed it to its conclusion. Decisively, the FIUV Ordo prints BOTH readings on the six shared dates, separated by a literal "-VEL-" token: the primary, strict- 1962 reading (feria wins, sine Gloria, no Te Deum) matches colitur exactly; the second, Cum-Sanctissima reading (saint kept, Gloria, Te Deum) matches the LMS Ordo exactly. F3 itself was never a real Te Deum finding: tools/extract_fiuv_ordo.ml's extract_te_deum scanned each block unbounded for "Ad Mat.", so on these six days -- whose primary office states no "Ad Mat." of its own -- it silently read the second office's own Te Deum instead. Fixed with a new split_at_alt_office, cutting every block at "-VEL-" before any field extraction runs; the alternative is captured, not discarded, in a new alt_te_deum field. A hard characterisation probe asserts the split fires on exactly the six known dates. Auditing for the same trap elsewhere (this is the third such manufactured divergence in this project) found a related but narrower marker, "Vel (sec. decretum <>) Missa ...", offering an alternate Mass formulary within a single office. It never corrupted Gloria/Credo (always stated before the marker on all 20 real instances, confirmed by diff), only the uncompared praef field; hardened defensively anyway, before it could ever fire live. The LMS Ordo (all three editions) carries no equivalent dual-print mechanism at all. expected-divergences-missalemeum.sexp's M27 is the same genus but was already correctly adjudicated, not touched. Both allow-list entries are rewritten, not deleted: the original SHAPE/ CITATION/WHY-NOT-FIXED-HERE reasoning is preserved verbatim as a recorded, superseded hypothesis, matching this project's own correction convention. test_lms_ordo.ml's matching predicate is unchanged (the 16-date population still fires, and always will, because it reflects a standing exclusion, not a bug); only its citation comment is corrected. test_fiuv_ordo.ml's F3-specific predicate/count assertion is removed, matching this file's own prior F2/F4 closure discipline. lib/ is untouched. dune test: 676/676. make check (COLITUR_EXHAUSTIVE_SWEEP=1, full 1583-9999 domain): 678/678.

feat(ef): the Gloria in excelsis, RG 431-432, deferring to Breviary 237-238

2026-08-22T15:56:42Z

Phase 2 of celebrant-rubrics-phase1: colitur rubrics gains a fifth column, whether the Gloria is said. Follows the Creed's own seam exactly -- Rite.t.gloria, Liturgical_day.t.gloria, wired through calendar.ml the same way. RG 431(a)/432(a) defer the Gloria to the Breviary's own Te Deum rule (nn. 237-238), so te_deum is implemented as its own named predicate, cited clause by clause, not collapsed into a colour heuristic. 431(c) (Holy Thursday, the Easter Vigil Mass) and 432(b)/(d) (violet; a Requiem) are independent overrides checked ahead of the Te Deum-derived answer. Every clause this engine has no dimension to model (votive Mass classes, the wider n.302 "Missa festiva" categories) is stated as N/A with its own reasoning, not silently dropped. Validated against the FIUV universal Ordo (Gloria and Te Deum) and all three LMS editions (Gloria). A first pass over-trusted a clean-looking 15-for-15 FIUV contradiction of 237(b)'s own Septuagesima exception and replaced it with a blanket "every Sunday" rule; the evidence was itself corrupted -- the FIUV extractor recognised only one of the source's two Te Deum negations ("non dicitur", not "sine"), so every "sine Te Deum" Sunday read wrongly true. Fixed in tools/extract_fiuv_ordo.ml, fixture re-extracted, and the literal 237(b) reading restored once the corrected data confirmed it. A second bug surfaced alongside it (Palm/ Passion Sunday wrongly reading true via Temporal_ef.named's own table membership, then Christ the King wrongly reading false from an over-broad fix) is closed with an explicit two-slug exclusion. Domain-wide 1583-9999: every violet or Rose day is gloria=false except the Easter Vigil (RG 431(c) lex specialis), every Requiem is gloria=false, both measured exhaustively, zero exceptions. Mutation- proved: disabling 431(c) reddens 8 tests including all four oracle comparisons; disabling 238(c)'s feria-I-classis exclusion reddens exactly the dedicated Ash Wednesday unit test, a genuine blind spot in both oracle layers, reported rather than hidden. Two open, cited findings, neither fixed here (out of this task's "follow creed's exact seam" scope): a privileged Lenten/Passiontide feria carrying one commemoration reads Gloria=true in the LMS Ordo but Te-Deum=true/Gloria=false in FIUV -- the two oracles disagree with each other, not merely with colitur (data/ef/expected-divergences-lms.sexp L5, expected-divergences-fiuv.sexp F3); and a pre-existing, uncited Colour.Violet bug on Rogation Monday/Tuesday in Temporal_ef.temporal, surfaced by this comparison but root-caused as a separate defect (L6). day/readings verified byte-identical against a build from the branch tip before this task (v0.10.1's own tag predates an already-landed bissextile fix that legitimately changed both, so it is not the right baseline). 671 tests green (dune test); 678 with the exhaustive sweep (COLITUR_EXHAUSTIVE_SWEEP=1 dune test --force, ~104s).

feat(ef): implement the calendarium's bissextile February shift

2026-08-22T14:40:24Z

The Missale Romanum's calendarium footnote for February (LT.txt:5011-5014, scan-corroborated scan2.txt:3050-3058): in a leap year the sixth kalends of March (24 February) is doubled rather than a 29th day appended, so St Matthias moves 24->25 February and St Gabriel of Our Lady of Sorrows 27->28, with 24 February itself carrying no fixed office that year. data/ef/expected-divergences-lms.sexp entry L3 tracked this as an open gap. Implemented as the rubric's own general mechanism (every fixed entry from 24 through 28 February shifts one civil day later in a leap year), not as "move these two named saints": the two readings are indistinguishable on shipped data (nothing else is fixed in that window) and diverge only for a future --overlay entry in the same range, which the mechanism reading covers correctly and a two-saints special case would not. This project has already been bitten once (RG 16(a)) by a rule implemented against shipped data's coincidental shape rather than the rubric itself. Kernel stays rite-agnostic: Rite.t gains a fixed_key field (Date.t -> (int * int) option), the same seam easter already establishes, read only by Layer.on_date's FIXED half -- the movable half (Easter_offset/Nth_weekday) is untouched. Default is the identity mapping, an optional argument on on_date, so every existing caller and every rite that supplies nothing is byte-identical to before this field existed. Date.is_leap is exposed in date.mli (already existed in date.ml) so the rite reads the kernel's own single-sourced leap-year definition. The EF implementation lives in Rite_ef.Temporal_ef.bissextile_fixed_key, fully cited, wired into Rite_ef.context. Blast radius, measured over the full 1583-9999 domain (Calendar.year run twice per civil year, real fixed_key vs identity, every day diffed): all 2,041 leap years in the domain show a visible change for each saint; 6,983 individual liturgical days change total, zero unclassified, across four shapes (Matthias vacates 24 Feb in 1,803 years / occupies 25 Feb in 1,811; Gabriel vacates 27 Feb in 1,699 / occupies 28 Feb in 1,670). L3's own prior estimate (1,650 years, observed-outright only) is confirmed close on the same definition (1,677 measured); the broader observed-or- commemorated count is higher, not lower, showing the narrow estimate undercounted visible impact rather than overcounting it. The lectio differential (2005-2050 fixture) gains a new cited entry, C40 in data/ef/expected-divergences.sexp: lectio implements no such shift, so every leap year in its window now diverges on the two shifted days (21 rows, not the naive 44 -- the comparator never compares commemorations, so a side where the shifted saint has zero comparator-visible footprint on both engines produces no row). The LMS Ordo's 2023-2024 fixture -- the window L3 was originally found in -- now matches on the Creed comparison; its formulary-override bucket count is corrected 182->181 (24 February leaves the counted Proper population, becoming Own_slug-sourced). The missalemeum oracle fixtures (2026-2027, 2038, 2035) cover no leap year and are unaffected. L3 is closed: converted from an active allow-list record to a prose closure paragraph (L1's own precedent), citation preserved verbatim, fix and measured blast radius recorded. The id-list assertion narrows to [L4] alone, and the now-dead "2024-02-24" -> "L3" date mapping is removed. Six golden values pinned across four new test cases: Matthias in a leap year (both the vacated and occupied sides) and a common-year control; Gabriel likewise, deliberately choosing a leap year where he is admitted only as an ordinary commemoration rather than winning outright, a different shape from Matthias's. Mutation-tested: forcing fixed_key back to identity reddens exactly five test cases -- the differential's Layer C count-pin (C40 drops to 0 actual vs 21 expected), the LMS Ordo's Creed and formulary-bucket checks, and both new golden pins -- confirming the tests actually exercise the fix. Reverted; dune test, the exhaustive sweep, and make check are all green.