OmniMemory Server

Quality Python 3.11+ License: MIT MCP

A production-friendly memory platform with an MCP server interface.

memory-mcp combines structured memory, semantic retrieval, knowledge graph operations, cross-session context, and safety controls in a self-hosted package.

Project overview

Why this project

• Works as an MCP backend for coding agents and assistants.
• Supports durable memory primitives (lessons, preferences, procedures, entities, relations).
• Includes search, extraction, consolidation, and quality/safety checks out of the box.
• Can run fully local (SQLite + local embeddings) or with PostgreSQL/Redis.

Built for OpenCode

This platform was actively developed and validated for OpenCode agent workflows.

• OpenCode website: https://opencode.ai
• OpenCode GitHub: https://github.com/anomalyco/opencode
• Typical usage: run Memory-MCP as MCP backend for OpenCode sessions and reusable memory.

Recommended agent prompt (memory policy)

For reliable model behavior and correct memory usage, configure your agent with this prompt:

• Memory agent prompt

Key capabilities

• Hybrid memory search: keyword + semantic retrieval.
• Cross-session memory and automatic context injection.
• Knowledge graph with triples, neighbor traversal, and path discovery.
• Auto-extraction pipeline for facts/events/preferences/relations/rules/skills.
• Document knowledge base (file/url/text ingestion + content search).
• Conversation history storage and retrieval.
• Procedural memory (how-to steps) and semantic entity graph.
• Memory lifecycle controls: TTL cleanup, decay/merge/prune consolidation.
• Reliability controls: circuit breaker, fallback mode, rate limiting, health endpoint.
• Multilingual heuristics for ru/uk/en with universal Unicode-safe token handling.

Technology stack

• Runtime: Python 3.11+, FastMCP, Pydantic Settings, asyncio-first service design.
• Primary storage: SQLite (default) with optional PostgreSQL backend parity.
• Optional infra: Redis (cache/rate limiting), Neo4j (graph backend).
• Retrieval: BM25/token search + vector semantic search + hybrid ranking.
• Embeddings providers: fastembed (local), OpenAI, Cohere.
• LLM providers: local and cloud providers via unified client (core/llm/client.py).
• Quality gates: Ruff, Pytest, focused mypy checks in CI.

What is stored in memory

Core memory domains

Domain	Purpose	Typical tools	Storage shape
Lessons	Durable technical takeaways and runbooks	memory_upsert, memory_search_lessons	key/value + metadata + timestamps
Preferences	User/agent stable preferences	memory_upsert, memory_search_preferences	key/value + source/lock/scope fields
Episodes	Session-level event log for consolidation	memory_consolidate	timestamped events and payloads
Working/session memory	Short-lived context per session	memory_search_all, cross_session_*	session-scoped records
Conversations	Ordered chat transcript storage	conversation_*	append-only messages with role/model/tokens
Knowledge base	Parsed documents from text/files/URLs	kb_*	docs + source metadata + search index
Knowledge graph	Facts as triples + graph traversal	kg_*	entities/predicates/triples (+ temporal events)
Procedural memory	How-to procedures and steps	memory_add_procedure	key/title/steps/metadata
Semantic graph	Generic entities and typed relations	memory_add_entity, memory_add_relation	entity nodes + relation edges

Retention defaults (configurable)

• Lessons: 90 days (OMNIMIND_MEMORY_LESSONS_TTL_DAYS)
• Episodes: 60 days (OMNIMIND_MEMORY_EPISODES_TTL_DAYS)
• Preferences: 180 days (OMNIMIND_MEMORY_PREFERENCES_TTL_DAYS)

How components are connected

End-to-end flow

1. MCP clients call tools/resources in mcp_server/memory_tools.py and mcp_server/memory_resources.py.
2. Wrappers ensure DB readiness and apply safety controls (rate limits, health checks, metrics).
3. core/memory.py orchestrates memory, retrieval, KB, KG, extraction, and cross-session workflows.
4. Subsystems persist through core/db.py using SQLite/Postgres, optional Redis, optional Neo4j.
5. Retrieval and graph operations feed back into agent context injection and downstream reasoning.

Relationship map (high-level)

• conversation_messages -> feed episodes -> promoted into lessons/preferences by consolidation.
• memory_docs + vector chunks -> hybrid search (keyword + semantic) for context recall.
• kg_triples represent current graph fact state; kg_triple_events preserve change history.
• Temporal KG tools (as_of, history, path_as_of) reason over event history, not only current state.
• Cross-session layer merges durable memory + recent session traces into token-bounded context bundles.

Architecture diagram

• Architecture diagram (PNG)

Diagram source notes: docs/architecture.md

Detailed data model and relationship map: docs/memory-data-model.md

Architecture overview

Core components:

• core/memory.py: high-level memory orchestration.
• core/memory_sqlite.py: storage layer and memory operations.
• core/search/*: BM25/hybrid retrieval, expansion, reranking.
• core/knowledge_graph.py + core/graph_db/neo4j_backend.py: graph operations.
• core/knowledge_base.py: KB documents and search.
• core/cross_session.py: cross-session lifecycle and context bundles.
• mcp_server/memory_tools.py: MCP tool surface.
• mcp_server/memory_resources.py: MCP resources.

Installation

Requirements:

• Python >=3.11

Install:

pip install -e .

For development:

pip install -e .[dev]

Quick start

Option 1: Local mode (SQLite, default)

cp .env.local .env
python -m mcp_server.server

Option 2: Docker infra (PostgreSQL + Redis)

./docker-compose.sh start
cp .env.docker .env
python -m mcp_server.server

Docker details: docker/README.md

Environment presets: ENV_CONFIGS.md

Search indexing (Google)

• Landing page: index.html
• Crawl rules: robots.txt
• Sitemap: sitemap.xml
• Full indexing guide: SEO_INDEXING.md
• Regenerate SEO assets: python3 scripts/generate_seo_assets.py

Configuration highlights

Common environment values:

# Database
OMNIMIND_DB_TYPE=sqlite
OMNIMIND_POSTGRES_ENABLED=false
OMNIMIND_SQLITE_ENABLED=true
OMNIMIND_DB_STRICT_BACKEND=false
OMNIMIND_DB_PATH=./memory.db

# Optional postgres/redis mode
OMNIMIND_DB_TYPE=postgres
OMNIMIND_POSTGRES_ENABLED=true
OMNIMIND_SQLITE_ENABLED=false
OMNIMIND_DB_STRICT_BACKEND=true
OMNIMIND_POSTGRES_HOST=localhost
OMNIMIND_POSTGRES_PORT=5442
OMNIMIND_POSTGRES_DB=memory
OMNIMIND_POSTGRES_USER=memory_user
OMNIMIND_POSTGRES_PASSWORD=***
OMNIMIND_REDIS_ENABLED=true

# Embeddings
OMNIMIND_EMBEDDINGS_PROVIDER=fastembed
OMNIMIND_EMBEDDINGS_FASTEMBED_MODEL=sentence-transformers/paraphrase-multilingual-MiniLM-L12-v2

# Optional Neo4j backend for knowledge graph
OMNIMIND_NEO4J_ENABLED=true
OMNIMIND_NEO4J_URI=bolt://localhost:7687
OMNIMIND_NEO4J_USER=neo4j
OMNIMIND_NEO4J_PASSWORD=***
OMNIMIND_NEO4J_DATABASE=neo4j

Notes:

• OMNIMIND_POSTGRES_ENABLED + OMNIMIND_SQLITE_ENABLED are the preferred toggles.
• If both are omitted, OMNIMIND_DB_TYPE is used for backward compatibility.
• If both toggles are set to the same value (true/true or false/false), runtime falls back to OMNIMIND_DB_TYPE.
• OMNIMIND_DB_STRICT_BACKEND=true turns backend mismatch into startup error (no silent fallback).
• PostgreSQL backend is used when a PostgreSQL driver is installed (psycopg2/psycopg) and postgres mode is requested.
• Check active backend at runtime via memory_health -> db_backend.

MCP tools

The server exposes the following MCP tools.

Memory search and storage

• memory_search
• memory_search_lessons
• memory_search_preferences
• memory_search_all
• memory_upsert
• memory_get
• memory_list
• memory_delete
• memory_index_workspace
• memory_health
• memory_ttl_cleanup
• memory_metrics

Memory consolidation and correction

• memory_consolidate
• memory_consolidate_decay
• memory_consolidation_status
• memory_correct
• memory_feedback

Procedural and semantic memory

• memory_add_procedure
• memory_get_procedure
• memory_search_procedures
• memory_add_entity
• memory_search_entities
• memory_add_relation
• memory_get_relations

Cross-session memory

• cross_session_start
• cross_session_message
• cross_session_tool_use
• cross_session_stop
• cross_session_end
• cross_session_context
• cross_session_search
• cross_session_stats
• cross_session_check_timeout

Conversation memory

• conversation_add_message
• conversation_get_messages
• conversation_get_messages_asc
• conversation_search
• conversation_stats

Knowledge base

• kb_add_document
• kb_add_document_from_file
• kb_add_document_from_url
• kb_get_document
• kb_list_documents
• kb_search_documents
• kb_delete_document
• kb_stats

Knowledge graph

• kg_add_triple
• kg_upsert_fact
• kg_get_triples
• kg_get_triples_as_of
• kg_get_fact_history
• kg_get_entity_timeline_summary
• kg_get_neighbors
• kg_find_path
• kg_find_path_as_of
• kg_search_entities
• kg_get_entity_facts
• kg_stats

Extraction pipeline

• extract_memories
• get_extracted_memories
• search_extracted_memories
• extraction_stats

MCP resources

• memory://lessons
• memory://preferences
• memory://health

MCP client examples

OpenCode

Example ~/.config/opencode/opencode.json snippet:

{
  "mcpServers": {
    "memory-mcp": {
      "command": "python",
      "args": ["-m", "mcp_server.server"],
      "cwd": "/path/to/memory"
    }
  }
}

Claude Desktop

Example claude_desktop_config.json snippet:

{
  "mcpServers": {
    "memory-mcp": {
      "command": "python",
      "args": ["-m", "mcp_server.server"],
      "cwd": "/path/to/memory"
    }
  }
}

Cursor

If your Cursor build supports MCP server config, use the same command pattern:

{
  "mcpServers": {
    "memory-mcp": {
      "command": "python",
      "args": ["-m", "mcp_server.server"],
      "cwd": "/path/to/memory"
    }
  }
}

Note: file locations and schema details may vary by client version.

Usage examples

Example: procedural + semantic memory

import asyncio
from mcp_server.memory_tools import (
    memory_add_procedure,
    memory_get_procedure,
    memory_add_entity,
    memory_add_relation,
    memory_get_relations,
)


async def demo() -> None:
    await memory_add_procedure(
        key="deploy.web",
        title="Deploy web service",
        steps=["Build image", "Run migrations", "Restart service"],
        metadata={"owner": "devops"},
    )

    procedure = await memory_get_procedure("deploy.web")
    print(procedure)

    service = await memory_add_entity("web-api", "service", {"lang": "python"})
    database = await memory_add_entity("postgres", "database", {"engine": "postgres"})
    await memory_add_relation(service["id"], "uses", database["id"], {"critical": True})

    relations = await memory_get_relations(service["id"])
    print(relations)


asyncio.run(demo())

Example: knowledge graph operations

import asyncio
from mcp_server.memory_tools import kg_add_triple, kg_get_neighbors, kg_find_path


async def demo_kg() -> None:
    await kg_add_triple("Alice", "works_for", "Acme", confidence=0.95, source_type="text")
    await kg_add_triple("Acme", "located_in", "Kyiv", confidence=0.9, source_type="text")

    neighbors = await kg_get_neighbors("Alice", direction="both", limit=20)
    print("neighbors:", neighbors)

    path = await kg_find_path("Alice", "Kyiv", max_depth=3)
    print("path:", path)


asyncio.run(demo_kg())

Example: temporal knowledge graph (evolving relationships)

import asyncio
from mcp_server.memory_tools import (
    kg_upsert_fact,
    kg_get_triples_as_of,
    kg_get_fact_history,
    kg_find_path_as_of,
)


async def demo_temporal() -> None:
    await kg_upsert_fact(
        "Alice",
        "works_for",
        "Acme",
        action="assert",
        observed_at="2026-01-01T10:00:00+00:00",
    )
    await kg_upsert_fact(
        "Alice",
        "works_for",
        "Contoso",
        action="assert",
        observed_at="2026-01-02T10:00:00+00:00",
    )

    old_state = await kg_get_triples_as_of(
        as_of="2026-01-01T12:00:00+00:00", subject="Alice", predicate="works_for"
    )
    print("as_of_old:", old_state)

    history = await kg_get_fact_history(subject="Alice", predicate="works_for", limit=20)
    print("history:", history)

    path = await kg_find_path_as_of(
        "Alice", "Kyiv", as_of="2026-01-03T00:00:00+00:00", max_depth=3
    )
    print("path_as_of:", path)


asyncio.run(demo_temporal())

Temporal predicate policy (default):

• single_active: works_for, belongs_to, prefers (new assert closes previous active object for same subject+predicate)
• multi_active: all other predicates (multiple active facts can coexist)

Configure single-active predicates via env:

OMNIMIND_KG_TEMPORAL_SINGLE_ACTIVE_PREDICATES=works_for,belongs_to,prefers

Reliability and safety

• Per-tool rate limiting.
• LLM circuit breaker with fallback behavior.
• Health snapshots with dependency status.
• Security/audit helpers in core/security.
• CI quality gates for lint, focused typing checks, and tests.

CI quality gates

Workflow: .github/workflows/quality.yml

• Ruff checks for critical modules.
• Focused mypy gate on runtime-critical paths.
• Full test suite with coverage threshold.
• Postgres fallback behavior check.

Development workflow

# Lint
ruff check .

# Tests
python -m pytest tests -q

# Focused mypy gate (same as CI)
python -m mypy core/security/audit.py core/security/gdpr.py core/search/bm25.py core/search/hybrid.py core/llm/client.py core/health/monitor.py core/knowledge_graph.py core/graph_db/neo4j_backend.py mcp_server/memory_tools.py --ignore-missing-imports --follow-imports=skip

Related docs

• Environment presets: ENV_CONFIGS.md
• Docker deployment: docker/README.md
• Install notes: INSTALL.md
• Memory data model and relationships: docs/memory-data-model.md
• Contributing guide: CONTRIBUTING.md
• Code of conduct: CODE_OF_CONDUCT.md
• Release process: RELEASE_CHECKLIST.md
• Security policy: SECURITY.md
• Google indexing guide: SEO_INDEXING.md

License

MIT. See LICENSE.