ASPECT_BACKEND_STANDARD

Moira Aspect Backend Standard

Governing Principle

The Moira aspect backend is a sovereign computational subsystem. Its definitions, layer boundaries, invariants, failure doctrine, and determinism rules are stated here and are frozen until explicitly superseded by a revision to this document.

This document reflects current implementation truth as of Phase 12 (272 passing tests). It does not describe aspirational future capabilities.

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Part I — Architecture Standard

1. Authoritative Computational Definitions

1.1 Ecliptic aspect

An ecliptic aspect in Moira is:

A detected angular relationship between two distinct celestial bodies whose angular separation along the ecliptic falls within a declared orb of a canonical aspect angle.

Element	Definition
two distinct bodies	body1 != body2; no self-aspects
angular separation	angular_distance(lon1, lon2) → [0, 180] degrees, folded at 180°
canonical aspect angle	An angle from moira.constants.Aspect.ALL
orb	abs(separation - angle)
within declared orb	orb <= allowed_orb
allowed_orb	default_orb * orb_factor, or the caller-supplied override for that angle

The admission test is fully reconstructable from the stored vessel:

orb        == abs(separation - angle)
orb        <= allowed_orb
separation  = angular_distance(lon1, lon2)

1.2 Declination aspect

A declination aspect in Moira is:

A parallel or contra-parallel between two distinct celestial bodies whose signed declinations satisfy one of the two defined relationships within a declared orb.

Type	Admission test	Orb formula
Parallel	abs(dec1 - dec2) <= allowed_orb	orb = abs(dec1 - dec2)
Contra-Parallel	abs(dec1 + dec2) <= allowed_orb	orb = abs(dec1 + dec2)

Declination aspects carry no motion data (applying, stationary are absent from DeclinationAspect).

1.3 Admitted aspect

An aspect is admitted when the admission test passes. Admission is binary: the aspect either qualifies or it does not. There is no partial admission and no confidence score at the detection layer.

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2. Layer Structure

The backend is organized into twelve phases. Each phase operates only on outputs produced by phases below it. No phase reaches upward.

Phase  1 — Core aspect detection
Phase  2 — Relational truth preservation
Phase  3 — Classification
Phase  4 — Inspectability
Phase  5 — Doctrine inputs
Phase  6 — Policy surface
Phase  7 — Geometric strength
Phase  8 — Temporal state
Phase  9 — Canonical configuration
Phase 10 — Multi-body pattern layer
Phase 11 — Relational graph / network layer
Phase 12 — Harmonic / family intelligence layer

Layer boundary rule

A function in phase N may consume results from phases 1 through N−1. It may not:

• re-run position arithmetic
• re-compute aspect admission
• alter a vessel produced by an earlier phase in place
• introduce new doctrine inputs not present in that phase's entry point

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3. Delegated Assumptions

The aspect engine delegates to external modules without redefining them:

Concern	Delegated to	Convention
Angular distance arithmetic	moira.coordinates.angular_distance	Returns [0, 180], fold at 180°
Canonical aspect definitions	moira.constants.Aspect.ALL	22 zodiacal aspects
Default orb table	moira.constants.DEFAULT_ORBS	{angle: max_orb}
Aspect tier lists	moira.constants.ASPECT_TIERS	Major / Common Minor / Extended Minor

The aspect backend does not redefine any of these. Changes to these constants propagate automatically.

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4. Canonical Aspect Set

The complete set of recognised and detectable aspect types is declared in CANONICAL_ASPECTS — a module-level tuple of 24 names, frozen at import time.

Tier	Count	Names
Major	5	Conjunction, Sextile, Square, Trine, Opposition
Common Minor	6	Semisextile, Semisquare, Sesquiquadrate, Quincunx, Quintile, Biquintile
Extended Minor	11	Septile, Biseptile, Triseptile, Novile, Binovile, Quadnovile, Decile, Tredecile, Undecile, Quindecile, Vigintile
Declination	2	Parallel, Contra-Parallel

Rules:

• The 22 zodiacal names correspond 1-to-1 with entries in Aspect.ALL.
• The 2 declination names are produced exclusively by find_declination_aspects.
• CANONICAL_ASPECTS carries no detection logic; it is a declaration only.
• No aspect not in CANONICAL_ASPECTS can be produced by any detection function.

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5. Classification

AspectClassification classifies every admitted aspect on three independent axes:

Axis	Type	Rule
domain	AspectDomain	ZODIACAL for ecliptic; DECLINATION for parallels
tier	AspectTier	Derived from AspectDefinition.is_major and membership in Aspect.EXTENDED_MINOR
family	AspectFamily	Derived from _FAMILY_BY_NAME; maps each aspect name to its harmonic family

Classification is descriptive only. It describes what was detected, not how it should be interpreted. Strength, dignity weighting, and reception scoring are excluded from the classification layer.

Family grouping

Aspects in the same harmonic series share a family:

Family	Members
CONJUNCTION	Conjunction
OPPOSITION	Opposition
SQUARE	Square
TRINE	Trine
SEXTILE	Sextile
SEMISEXTILE	Semisextile
SEMISQUARE	Semisquare
SESQUIQUADRATE	Sesquiquadrate
QUINCUNX	Quincunx
QUINTILE	Quintile, Biquintile
SEPTILE	Septile, Biseptile, Triseptile
NOVILE	Novile, Binovile, Quadnovile
DECILE	Decile, Tredecile
UNDECILE	Undecile
QUINDECILE	Quindecile
VIGINTILE	Vigintile
DECLINATION	Parallel, Contra-Parallel

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6. Policy Layer

AspectPolicy encapsulates all detection-time doctrine inputs.

Field	Type	Default	Effect
tier	int | None	None	0=Major only, 1=Major+Common Minor, 2=All; None defers to include_minor
include_minor	bool	True	Include Common Minor when tier is None
orbs	dict[float, float] | None	None	Custom orb table {angle: max_orb}; overrides orb_factor when set
orb_factor	float	1.0	Multiplier on all default orbs; ignored when orbs is set
declination_orb	float	1.0	Ceiling for Parallel and Contra-Parallel detection

When a policy argument is passed to a detection function it takes full precedence over any corresponding individual keyword arguments. Individual parameters remain available for backward compatibility.

DEFAULT_POLICY reproduces the historical default behaviour of all four detection functions.

Policy validation

AspectPolicy validates its fields at construction:

Condition	Raises
orb_factor <= 0	ValueError
declination_orb < 0	ValueError

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7. Geometric Strength

AspectStrength is a pure arithmetic exactness summary derived from orb and allowed_orb only.

surplus   = allowed_orb - orb
exactness = 1.0 - orb / allowed_orb

Field	Definition
orb	Angular deviation from target angle; always non-negative
allowed_orb	Orb ceiling applied at admission
surplus	allowed_orb - orb; remaining headroom
exactness	1.0 - orb / allowed_orb; 1.0 = exact, 0.0 = at boundary

aspect_strength does not interpret strength. It does not weight by aspect family, body dignity, or orbital speed.

Strength validation

aspect_strength validates its input before computing:

Condition	Raises
allowed_orb <= 0	ValueError
orb > allowed_orb	ValueError

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8. Temporal-State Doctrine

MotionState formalises the motion-aware truth already stored in applying and stationary. It maps the complete decision space without ambiguity:

Vessel type	stationary	applying	→ MotionState
DeclinationAspect	—	—	NONE
AspectData	True	any	STATIONARY
AspectData	False	True	APPLYING
AspectData	False	False	SEPARATING
AspectData	False	None	INDETERMINATE

STATIONARY takes precedence over applying regardless of its value. DeclinationAspect always yields NONE because declination detection receives no speed inputs.

Temporal consistency rules

• APPLYING ↔ is_applying is True and is_separating is False
• SEPARATING ↔ is_separating is True and is_applying is False
• is_applying and is_separating are never simultaneously True
• Both are False when applying is None

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9. Multi-Body Pattern Doctrine

find_patterns operates over an already-admitted list[AspectData]. It does not re-run position arithmetic.

Implemented patterns and their structural requirements:

Kind	Bodies	Required edges
STELLIUM	≥3, maximal clique	Mutual Conjunction between every pair
T_SQUARE	exactly 3	One Opposition (A–B) + Square(A–C) + Square(B–C)
GRAND_TRINE	exactly 3	Trine(A–B) + Trine(B–C) + Trine(A–C)
GRAND_CROSS	exactly 4	Two Oppositions + four Squares (closed cross)
YOD	exactly 3	Sextile(B–C) + Quincunx(A–B) + Quincunx(A–C)

Pattern ordering rules

• Output order: Stellia, T-Squares, Grand Trines, Grand Crosses, Yods.
• Each pattern kind is emitted at most once per unique body set (frozenset).
• Stellium: smaller subsets contained within a larger Stellium are suppressed.
• All other kinds are independent. A Grand Cross may also contain T-Squares; both are reported.
• Within each kind, patterns are ordered by sorted body-name iteration (outer loops always iterate over sorted(all_bodies)).

Pattern contributing-aspects ordering

The aspects tuple inside each AspectPattern is sorted by (body1, body2, aspect). This ordering is stable and independent of the input list ordering.

Structural aspect counts

Kind	len(aspects)
STELLIUM (3-body)	3
STELLIUM (4-body)	6
T_SQUARE	3
GRAND_TRINE	3
GRAND_CROSS	6
YOD	3

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10. Relational Graph Doctrine

build_aspect_graph expresses the chart as a deterministic aspect network. Bodies become nodes; each admitted AspectData becomes an edge.

Graph construction rules

• Every body that appears in at least one aspect gets a node.
• Bodies supplied via bodies= that have no aspects get degree-0 nodes.
• nodes is sorted by body name.
• edges is sorted by (body1, body2, aspect).
• components is sorted by (min(component), len(component)) ascending.

Node invariants

Invariant	Expression
Degree consistency	degree == len(edges)
Family count consistency	sum(family_counts.values()) == degree
Incidence	Every edge in node.edges has body1 == name or body2 == name
Edge ordering	edges sorted by (body1, body2, aspect)

family_counts keys are AspectData.aspect strings (e.g. "Trine"), not AspectFamily enum values. This is intentional: it preserves per-name granularity at the graph layer (Trine vs Biquintile both count as QUINTILE family at the harmonic layer, but remain distinct at the graph layer).

Derived properties

Property	Definition
hubs	Nodes with maximum degree; empty tuple when all nodes are isolated
isolated	Nodes with degree 0, sorted by name

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11. Harmonic Intelligence Doctrine

aspect_harmonic_profile derives the family distribution of admitted aspects at both the chart level and per body.

Profile construction rules

• chart covers all aspects in the input list.
• by_body has one entry per body that appears in at least one aspect.
• by_body keys are in sorted body-name order.
• A body with no aspects has no entry in by_body.

Family resolution order (when classification is absent)

1. a.classification.family when classification is not None (normal case).
2. _FAMILY_BY_NAME[a.aspect] when classification is None and the name is a known zodiacal name.
3. AspectFamily.DECLINATION as the fallback for any unrecognised name (covers "Parallel", "Contra-Parallel", or custom names).

AspectFamilyProfile invariants

Invariant	Expression
Total	sum(counts.values()) == total
Proportions count	len(proportions) == len(counts)
Proportions sum	abs(sum(proportions.values()) - 1.0) < 1e-9 when total > 0
Dominant membership	Every member of dominant is a key in counts
Proportion range	All proportions in [0.0, 1.0]
Key ordering	counts and proportions keys follow AspectFamily declaration order
Dominant ordering	dominant sorted by AspectFamily.value (alphabetical)

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12. Non-Goals

The following concerns are explicitly outside the scope of the current aspect backend:

Excluded concern	Reason
Interpretation (e.g. "this aspect is challenging")	Doctrine-specific; belongs above the engine
Dignity weighting or reception scoring	Requires a separate dignity model
Body-specific orb weights	Not in current AspectPolicy
Sinister/dexter distinction	Requires directional awareness not yet in scope
Antiscion contacts	A separate geometric computation
Cross-chart (synastry) relational policies	Multi-chart context not yet in scope
Kite, Mystic Rectangle, Grand Quintile	Require oriented topology or 5-body matching
UI rendering or serialization	Belongs above the engine
Harmonic chart generation	Separate from aspect detection

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Part II — Validation Codex

1. Validation Environment

Property	Value
Authoritative runtime	.venv in the project root
Python version	3.14.x (as resolved by .venv)
Test runner	pytest via .venv\Scripts\python.exe -m pytest
Test file	tests/unit/test_aspects.py
Baseline	272 tests, all passing
Acceptable result	0 failures, 0 errors

No test in test_aspects.py may be modified to make the implementation pass. A failing test is always treated as an implementation defect, not a test defect, unless the test itself is proven incorrect.

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2. Invariant Register

This register is the normative source of truth for all subsystem invariants. Each invariant is identified by a short code for traceable reference.

INV-TRUTH — Truth preservation

Code	Invariant
T-1	orb == abs(separation - angle) to floating-point precision
T-2	orb <= allowed_orb for every admitted AspectData
T-3	orb_surplus == allowed_orb - orb >= 0
T-4	separation is in [0, 180] degrees
T-5	For a Parallel: orb == abs(dec1 - dec2)
T-6	For a Contra-Parallel: orb == abs(dec1 + dec2)
T-7	dec1 and dec2 are in [-90, +90]

INV-CLASS — Classification

Code	Invariant
C-1	classification.domain == ZODIACAL for every AspectData produced by detection
C-2	classification.domain == DECLINATION for every DeclinationAspect
C-3	classification.family == _FAMILY_BY_NAME[aspect] for every zodiacal aspect
C-4	classification.family == AspectFamily.DECLINATION for every DeclinationAspect
C-5	classification.tier == MAJOR for every aspect in {"Conjunction","Sextile","Square","Trine","Opposition"}
C-6	Classification is identical for the same aspect name across all calls

INV-STR — Geometric strength

Code	Invariant
S-1	0.0 <= orb <= allowed_orb for any vessel passed to aspect_strength
S-2	surplus == allowed_orb - orb
S-3	0.0 <= exactness <= 1.0
S-4	exactness == 1.0 - orb / allowed_orb
S-5	aspect_strength raises ValueError when allowed_orb <= 0
S-6	aspect_strength raises ValueError when orb > allowed_orb

INV-MOT — Temporal state

Code	Invariant
M-1	APPLYING ↔ is_applying is True and is_separating is False
M-2	SEPARATING ↔ is_separating is True and is_applying is False
M-3	STATIONARY when stationary is True, regardless of applying value
M-4	INDETERMINATE when applying is None and stationary is False
M-5	DeclinationAspect always yields MotionState.NONE
M-6	is_applying and is_separating are never simultaneously True

INV-PAT — Pattern layer

Code	Invariant
P-1	Every body in pattern.bodies appears in at least one aspect in pattern.aspects
P-2	pattern.aspects is sorted by (body1, body2, aspect)
P-3	No pattern body-set is emitted more than once per kind
P-4	Stellium sub-cliques contained in a larger Stellium are suppressed
P-5	T_SQUARE has exactly 3 contributing aspects
P-6	GRAND_TRINE has exactly 3 contributing aspects
P-7	GRAND_CROSS has exactly 6 contributing aspects
P-8	YOD has exactly 3 contributing aspects
P-9	STELLIUM (3-body) has exactly 3; (4-body) has exactly 6 contributing aspects
P-10	Output order: Stellia, T-Squares, Grand Trines, Grand Crosses, Yods
P-11	find_patterns does not mutate the input list

INV-GRAPH — Relational graph

Code	Invariant
G-1	degree == len(edges) for every node
G-2	sum(family_counts.values()) == degree for every node
G-3	Every edge in node.edges involves that node as body1 or body2
G-4	node.edges sorted by (body1, body2, aspect)
G-5	graph.nodes sorted by body name
G-6	graph.edges sorted by (body1, body2, aspect)
G-7	graph.components sorted by (min(c), len(c)) ascending
G-8	build_aspect_graph does not mutate the input list

INV-HARM — Harmonic layer

Code	Invariant
H-1	sum(counts.values()) == total
H-2	len(proportions) == len(counts)
H-3	abs(sum(proportions.values()) - 1.0) < 1e-9 when total > 0
H-4	Every member of dominant is a key in counts
H-5	All proportions are in [0.0, 1.0]
H-6	chart.total == len(aspects)
H-7	by_body[name].total equals the number of aspects in which name participates
H-8	by_body keys are in sorted body-name order
H-9	aspect_harmonic_profile does not mutate the input list

INV-POL — Policy

Code	Invariant
PO-1	AspectPolicy raises ValueError when orb_factor <= 0
PO-2	AspectPolicy raises ValueError when declination_orb < 0
PO-3	DEFAULT_POLICY is a valid, constructable AspectPolicy

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3. Determinism Register

The following ordering guarantees are normative. Any permutation of an input list must produce identical output on all of these:

Context	Determinism guarantee
find_aspects result order	Sorted by orb ascending
find_declination_aspects result order	Sorted by orb ascending
find_patterns — pattern order	Stellia, T-Squares, Grand Trines, Grand Crosses, Yods
find_patterns — body-set per pattern	frozenset (order-independent identity)
find_patterns — aspects tuple	Sorted by (body1, body2, aspect)
build_aspect_graph — nodes	Sorted by body name
build_aspect_graph — edges	Sorted by (body1, body2, aspect)
build_aspect_graph — components	Sorted by (min(c), len(c))
build_aspect_graph — node.edges	Sorted by (body1, body2, aspect)
aspect_harmonic_profile — by_body keys	Sorted body-name order
aspect_harmonic_profile — counts keys	AspectFamily declaration order
aspect_harmonic_profile — dominant	Sorted by AspectFamily.value (alphabetical)

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4. Failure Doctrine

The following table lists every condition that raises an exception, the exception type, and the diagnostic guarantee:

Function / constructor	Condition	Exception	Diagnostic guarantee
aspect_strength	allowed_orb <= 0	ValueError	Message includes "allowed_orb" and the offending value
aspect_strength	orb > allowed_orb	ValueError	Message includes "orb" and both values
AspectPolicy	orb_factor <= 0	ValueError	Message includes "orb_factor"
AspectPolicy	declination_orb < 0	ValueError	Message includes "declination_orb"

All other functions in the backend are pure computations over valid inputs. They do not raise on empty lists; they return empty results.

Behaviour on empty input

Function	Input	Returns
find_aspects	{}	[]
find_declination_aspects	{}	[]
find_patterns	[]	[]
build_aspect_graph	[]	AspectGraph(nodes=(), edges=(), components=())
aspect_harmonic_profile	[]	AspectHarmonicProfile(chart=empty, by_body={})

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5. No-Mutation Guarantee

Every public function beyond the detection layer accepts its inputs by value and does not mutate them:

Function	Guarantee
find_patterns(aspects)	Does not alter aspects or any element of it
build_aspect_graph(aspects, ...)	Does not alter aspects or any element of it
aspect_harmonic_profile(aspects)	Does not alter aspects or any element of it
aspect_strength(aspect)	Does not alter aspect
aspect_motion_state(aspect)	Does not alter aspect

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6. Cross-Layer Consistency Rules

These rules govern the logical relationship between layers. Each rule must hold on any output produced by the detection layer.

Rule	Expression
Classification–family	a.classification.family == _FAMILY_BY_NAME[a.aspect] for all zodiacal AspectData
Classification–domain	a.classification.domain == ZODIACAL for all AspectData
Strength–surplus	a.orb_surplus == aspect_strength(a).surplus
Graph–harmonic	sum(node.family_counts.values()) == hp.by_body[node.name].total for every node
Harmonic–total	hp.chart.total == len(aspects)
Motion–is_applying	aspect_motion_state(a) == APPLYING ↔ a.is_applying is True
Motion–is_separating	aspect_motion_state(a) == SEPARATING ↔ a.is_separating is True
is_major–is_minor	a.is_major != a.is_minor for any classified AspectData
partile–platic	a.is_platic == (not a.is_partile) for any AspectData

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7. Public Surface Register

Complete public surface of moira.aspects as of Phase 12:

Enumerations

Name	Values
AspectDomain	ZODIACAL, DECLINATION
AspectTier	MAJOR, COMMON_MINOR, EXTENDED_MINOR
AspectFamily	17 members (see Section 5, Family grouping)
MotionState	APPLYING, SEPARATING, STATIONARY, INDETERMINATE, NONE
AspectPatternKind	STELLIUM, T_SQUARE, GRAND_TRINE, GRAND_CROSS, YOD

Frozen dataclasses

Name	Fields
AspectClassification	domain, tier, family
AspectPolicy	tier, include_minor, orbs, orb_factor, declination_orb
AspectStrength	orb, allowed_orb, surplus, exactness
AspectPattern	kind, bodies, aspects
AspectGraphNode	name, degree, edges, family_counts
AspectGraph	nodes, edges, components; properties hubs, isolated
AspectFamilyProfile	counts, total, proportions, dominant
AspectHarmonicProfile	chart, by_body

Mutable dataclasses (intentionally not frozen)

Name	Rationale
AspectData	Detection functions populate fields after construction
DeclinationAspect	Detection functions populate fields after construction

Both vessels are terminal (not designed for subclassing) and document their structural invariants explicitly in their class docstrings.

Module-level constants

Name	Type	Content
CANONICAL_ASPECTS	tuple[str, ...]	24 canonical aspect names
DEFAULT_POLICY	AspectPolicy	Policy matching historical detection defaults

Detection functions

Name	Signature	Returns
find_aspects	(positions, *, include_minor, tier, orbs, orb_factor, policy)	list[AspectData]
aspects_between	(body1, lon1, speed1, body2, lon2, speed2, ...)	list[AspectData]
aspects_to_point	(positions, point_name, point_lon, ...)	list[AspectData]
find_declination_aspects	(declinations, *, orb, policy)	list[DeclinationAspect]

Derived-layer functions

Name	Input	Returns
aspect_strength	AspectData | DeclinationAspect	AspectStrength
aspect_motion_state	AspectData | DeclinationAspect	MotionState
find_patterns	list[AspectData]	list[AspectPattern]
build_aspect_graph	list[AspectData], bodies=None	AspectGraph
aspect_harmonic_profile	list[AspectData]	AspectHarmonicProfile

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8. Validation Baseline

As of Phase 12:

272 tests passing
0 failures
0 errors
Runtime: ~0.7 seconds

Test categories by phase:

Phase	Subject	Approximate test count
1–4	Detection, truth preservation, classification, inspectability	~45
5–6	Policy, strength	~20
7–8	Temporal state, strength invariants	~20
9	Canonical aspects	~22
10	Pattern detection	~24
11	Pattern hardening, permutation invariance	~28
12–13	Graph layer	~36
14	Harmonic layer	~36
15	Subsystem hardening, cross-layer consistency	~31
Total		272

All tests validate against the authoritative .venv runtime. No test may be modified to accommodate an implementation change; implementation must satisfy the tests as written.