Glossary

Domain terms used across HydraMem. Use these definitions to avoid semantic drift.

Term	Definition
SR-MKG	Structured Relation – Mutual Knowledge Graph. A pure-Python, topological scorer that ranks/filters candidate relations using graph structure and heuristic weights — no LLM. Stage 1 of verification.
VoG	Verification of Groundedness. An LLM step that checks whether a candidate is grounded in retrieved evidence. Stage 2 of verification; also used for the chunk path.
Chunk prefilter	The vector-similarity (cosine) filter applied to chunks inside hydra_search. It is not SR-MKG; only relations go through SR-MKG.
Night Gardener	The autonomous offline cycle that runs in three phases — infer → verify → prune — to refine the graph. Honest contract: emits zero relations when there is no real evidence.
Fast path	Low-latency retrieval with no LLM: vector ANN + entity term match + 1-hop expansion. Used by priming_context.
Full path	High-precision retrieval: vector ANN + multi-hop graph traversal + SR-MKG + VoG. Used by hydra_search.
priming_context	Fast-path tool returning top-k chunks + neighbouring entity names for the agent to expand.
hydra_search	Full-path tool returning verified context with metadata.
expand_context	Multi-hop graph traversal from known entity IDs.
trace_path	Shortest path between two entities (NetworkX shortest_path).
MENTIONS	The edge type linking a chunk to an entity it references.
Hyper-relational qualifier	Extra key/value context attached to a relation (subject–predicate–object + qualifiers), making relations first-class hyper-edges.
PPR	Personalized PageRank retrieval (HippoRAG-style), in hydramem/ppr.py.
CRDT	Conflict-free Replicated Data Type, used by the garden (hydramem/garden/crdt.py) for mergeable state.
LightGNN pruning	Optional GNN-based spurious-edge detection (hydramem/gnn_prune.py); heuristic fallback; auto-skips on graphs larger than HYDRAMEM_GNN_MAX_NODES.
Honesty contract	The project rule that no feature/metric is described as working unless it measurably works; the dashboard must reflect reality.
Shadow estimator	The naive-RAG baseline used to estimate token savings (hydramem/telemetry/shadow.py); the source of the "tokens saved" metric.
Grafeo / LadybugDB	The persistent graph backend (Grafeo = Rust core via PyO3; LadybugDB = a Kuzu fork). On Python 3.11 the graph falls back to a NetworkX persistent store.
LanceDB	The persistent vector store for chunks + embeddings.
fastembed	The default lightweight ONNX embedder (~80 MB, no torch); falls back to sentence-transformers when configured.
MCP	Model Context Protocol — the agent-facing tool protocol served by FastMCP in hydramem/server.py.
Project namespacing	Per-project isolation of stored data so multiple knowledge bases coexist in one deployment.
min_repeat_count	Night Gardener config gating how many times a session snapshot must repeat before it is considered for inference (default 2).
Calibration	Per-project tuning of SR-MKG/verification thresholds (tests/test_calibration.py).