Muhurta Lagna composition standard

Date: 9 October 2026. Owner: moira/muhurta_lagna.py and moira/muhurta_lagna_dated.py. Source decisions and fixtures control this finite VED-010 admission; validation records executed checks.

1. Public contract

evaluate_muhurta_lagna_strength(sidereal_longitudes, *, jd_ut1, lagna_sidereal_longitude=None, natal_moon_sidereal_longitude=None, natal_lagna_sidereal_longitude=None, shadbala_result=None, policy=None) returns independently inspectable Lagna/Navamsa/placement/strength components. The mapping admits any subset of the nine named Vedic bodies; numeric inputs are finite and uncoerced, angles in[0,360). Opposite nodes must agree both geometrically (1e-9-degree representation tolerance) and by sign. Missing Lagna, bodies, natal reference or strength remain explicitly unavailable where needed; an incomplete chart never earns a normalized total.

MuhurtaLagnaPolicy selects the purpose, Navamsa reading, optional Parihara and named ayanamsa. Applied house/aspect/relationship/nature/strength policies are returned. No unspecified house or aspect school is selected invisibly. The catalogue enumerates these choices, endpoint conventions and exclusions. The source record contains their full rule definitions and attribution limits.

2. Snapshot and strength context

muhurta_lagna_for_datetime(dt, latitude, longitude, *, policy=None, include_shadbala=False, hora_lord=None, natal_moon_sidereal_longitude=None, natal_lagna_sidereal_longitude=None, reader=None) admits an aware, real civil instant; no naive datetime, Unix timestamp or nonexistent local time. Latitude is[-90,90], longitude[-180,180]. Exact poles return unavailable Lagna geometry. A missing kernel/clock/anchor raises MuhurtaResourceError; an uncovered epoch raises MuhurtaCoverageError. Borrowed readers are never closed or replaced.

The snapshot carries the resolved epoch, reader binding, node mode, longitude frame and actual inputs. Lagna geometry uses the canonical house owner. Shadbala is opt-in, with declared Porphyry geometry, JD weekday, actual sunrise/sunset day/night and optional caller hora lord. It exposes every existing component; it does not act as a surrogate for dignity or cancel restrictions by threshold. For direct Shadbala input, matching epoch/frame and consistent arithmetic are required; observational authenticity remains the caller's responsibility.

3. Interpretation of results

The general and marriage profiles are separate. The marriage result contains MC 87/92's0-20 Lagna placement score, which is neither Shadbala nor Varga Vimshopaka. At commentary endpoints10 and 15 both applicable bands are returned. Its favorable label does not override an independent restriction.

Rules have nullable truth and named prerequisites. Restrictions retain raw detection after an opt-in MC 88 exception. A missing prerequisite can produce unavailable or exception_unavailable; a known sufficient alternative can still establish an exception. The existing six VED-009 temporal detectors are not automatically modified. activity_suitability="not_evaluated" is always returned. Continuous windows and complete purpose elections are outside this snapshot product.

4. REST and compatibility

• GET /v1/muhurta/lagna/catalogue: kernel-free profile discovery.
• POST /v1/muhurta/lagna/direct: caller-supplied sidereal facts and optional complete Shadbala receipt.
• POST /v1/muhurta/lagna/datetime: the serving engine's reader-derived snapshot.

Requests forbid extra fields, unsupported policies, boolean/string numeric coercion, nonfinite values, invalid node geometry and stale/malformed strength receipts. All responses use declared models. Resource errors are 503; coverage and invalid input errors are 422. Serializers project the canonical engine result and do not own doctrinal rules.

The shared D9 boundary fix changes incorrectly assigned exact/subdivision edge values. The source-backed Venus-to-Moon enemy correction changes Cancer dignity and consumers of natural/compound relations. These changes preserve the existing algorithms' declared authorities rather than introducing a second incompatible table. Other Varga methods, legacy Muhurta score/search, Tara/Chandra policy and VED-009 detection contracts are preserved.

Strength repair follow-through — 9 October 2026

shadbala_result now retains the complete supplied/derived strength receipt alongside the per-planet summary, including context, selected Saptavargaja scale and canonical war ledger. Direct REST input accepts the engine dataclass shape, including paired-array evidence. Signed canonical Kala war adjustments are admitted only with their checked ledger; corrupted sums/thresholds/evidence still reject. Missing polar solar events preserve Lagna evidence with shadbala_basis=unavailable_shadbala_solar_geometry and no fabricated strength.

The second adversarial repair canonicalizes admitted classical-planet positions from the Shadbala context before computing Lagna signs, Navamsas, houses, predicates and placement scores. A tolerated difference across a discrete boundary therefore cannot contradict the attached strength evidence. Missing input bodies remain missing, and supplied nodes remain unchanged. Context-backed positional components are recomputed during direct admission; balanced edits that preserve totals still reject. Dated strength uses the same explicitly declared civil-UTC weekday as the Shadbala REST products.