Knowledge Graph

MemPalace includes a temporal entity-relationship graph — like Zep's Graphiti, but SQLite instead of Neo4j. Local and free.

What It Stores

Entity-relationship triples with temporal validity:

Subject → Predicate → Object [valid_from → valid_to]

Facts have time windows. When something stops being true, you invalidate it — and historical queries still find it.

Usage

Python API

from mempalace.knowledge_graph import KnowledgeGraph

kg = KnowledgeGraph()

# Add facts
kg.add_triple("Kai", "works_on", "Orion", valid_from="2025-06-01")
kg.add_triple("Maya", "assigned_to", "auth-migration", valid_from="2026-01-15")
kg.add_triple("Maya", "completed", "auth-migration", valid_from="2026-02-01")

# Query: everything about Kai
kg.query_entity("Kai")
# → [Kai → works_on → Orion (current), Kai → recommended → Clerk (2026-01)]

# Query: what was true in January?
kg.query_entity("Maya", as_of="2026-01-20")
# → [Maya → assigned_to → auth-migration (active)]

# Timeline
kg.timeline("Orion")
# → chronological story of the project

Invalidating Facts

When something stops being true:

kg.invalidate("Kai", "works_on", "Orion", ended="2026-03-01")

Now queries for Kai's current work won't return Orion. Historical queries still will.

MCP Tools

Through the MCP server, the knowledge graph is available as tools:

Tool	Description
mempalace_kg_query	Query entity relationships with time filtering
mempalace_kg_add	Add facts
mempalace_kg_invalidate	Mark facts as ended
mempalace_kg_timeline	Chronological entity story
mempalace_kg_stats	Graph overview

Storage

The knowledge graph uses SQLite with two tables:

entities — people, projects, tools, concepts:

• id — lowercase normalized name
• name — display name
• type — person, project, tool, concept, etc.
• properties — JSON blob for extra metadata

triples — relationships between entities:

• subject → predicate → object
• valid_from — when this became true
• valid_to — when it stopped being true (NULL = still current)
• confidence — 0.0 to 1.0
• source_closet — link back to the verbatim memory

Database location: ~/.mempalace/knowledge_graph.sqlite3

Comparison

Feature	MemPalace	Zep (Graphiti)
Storage	SQLite (local)	Neo4j (cloud)
Cost	Free	$25/mo+
Temporal validity	Yes	Yes
Self-hosted	Always	Enterprise only
Privacy	Everything local	SOC 2, HIPAA