Encoder Coverage Map

Encoder	Intended Scenario	What It Encodes	Primary Output	Cited Example/Test
`HGraphEncoder`	General state encoding with optional goals/actions/history	Objects, facts, optional goal/action/history structures	`BatchEncoding` (hetero)	`examples/encoders/hetero_encoder_example.py`, `tests/encoding/test_batch_encoding.py`
`FlatRelationEncoder`	Compact packed state/goal/action/history encoding	Packed relation tensors plus target-entity metadata	`BatchEncoding` (flat-on-homo carrier)	`examples/encoders/flat_relation_encoder_example.py`, `tests/encoding/test_flat_relation_encoder.py`
`HorizonEncoder`	Root + lookahead candidate reasoning	Root state with `TransitionDAG` target/candidate relations	`BatchEncoding` (hetero)	`examples/encoders/horizon_hetero_encoder_example.py`, `tests/encoding/test_horizon_encoder.py`
`FlatHorizonEncoder`	Compact root + lookahead candidate reasoning	Packed flat relations with state-target carrier rows from `TransitionDAG`	`BatchEncoding` (flat-on-homo carrier)	`tests/encoding/test_flat_horizon_encoder.py`
`TransitionHGraphEncoder`	Full transition modeling	Source + successor structures in one transition graph	`BatchEncoding` (hetero)	`examples/encoders/transition_hetero_encoder_example.py`, `tests/encoding/test_transition_hetero_encoder.py`
`TransitionEffectsHGraphEncoder`	Effect/delta transition learning	Transition-focused deltas/effects representation	`BatchEncoding` (hetero)	`examples/encoders/transition_change_hetero_encoder_example.py`, `tests/encoding/test_transition_change_encoder.py`
`FlatTransitionEncoder`	Compact full transition modeling	One-step successor encoding over the flat state-target substrate	`BatchEncoding` (flat-on-homo carrier)	`examples/encoders/flat_transition_encoder_example.py`, `tests/encoding/test_flat_transition_encoder.py`
`FlatTransitionEffectsEncoder`	Compact effect/delta transition learning	One-step delta/effects encoding over the flat state-target substrate	`BatchEncoding` (flat-on-homo carrier)	`examples/encoders/flat_transition_encoder_example.py`, `tests/encoding/test_flat_transition_encoder.py`
`ColorEncoder`	Compact homogeneous baselines	Integer-style color/object/predicate/action features	`BatchEncoding` (homo)	`examples/encoders/color_encoder_example.py`, `tests/encoding/test_color_encoder.py`
`ILGEncoder`	Python ILG feature construction	ILG atom/object/action topology and statuses	`BatchEncoding` (hetero)	`examples/encoders/ilg_hetero_encoder_example.py`, `tests/encoding/test_custom_python_encoder_example.py`

Streams and Dynamic Fields Coverage

Stream semantics/parity: tests/encoding/test_stream_encoder.py
Flat stream semantics/parity: tests/encoding/test_flat_stream_encoder.py
Dynamic graph fields/collation: tests/encoding/test_dynamic_graph_fields.py

LGAN Surface

HGraphEncoder and FlatRelationEncoder share the same main-lane LGAN API: include_lgan_edges, lgan_*_edge_pos, and lgan_anchor_sources.
HorizonEncoder and FlatHorizonEncoder use candidate state rows as LGAN anchors and do not expose lgan_anchor_sources.
Transition encoders on both lanes follow the horizon rule.