hermes-agent/plugins/memory/mem0_oss

Mem0 OSS Memory Plugin

Self-hosted, privacy-first long-term memory using the open-source mem0ai library. No cloud API key or external service needed — everything runs on your machine.

How it works

• LLM fact extraction — after each conversation turn, mem0 uses an LLM to extract important facts, preferences, and context from the exchange.
• Semantic search — memories are stored in a local Qdrant vector database. Searches use embedding-based similarity so natural-language queries work well.
• Automatic deduplication — mem0 merges new facts with existing ones to avoid duplicate storage.
• Built-in memory mirroring — writes via the built-in memory tool are automatically mirrored into mem0 via on_memory_write, so nothing is lost whether you use the native tool or the mem0-specific tools.

Setup

1. Install dependencies

pip install mem0ai qdrant-client

2. Configure a backend

Zero extra config — auto-detect (recommended)

If you already have a Hermes provider configured (OpenRouter, Anthropic, OpenAI, or AWS Bedrock), mem0 OSS will automatically pick it up — no MEM0_OSS_* vars needed. The plugin mirrors the standard Hermes auxiliary provider priority:

OPENROUTER_API_KEY  →  uses OpenRouter (openrouter → openai adapter)
ANTHROPIC_API_KEY   →  uses Anthropic directly
OPENAI_API_KEY      →  uses OpenAI (+ OPENAI_BASE_URL if set)
AWS_ACCESS_KEY_ID   →  uses AWS Bedrock (boto3 reads creds automatically)

The first matching key wins.

Option A — config.yaml (preferred for per-provider control)

The plugin inherits from auxiliary.default if no auxiliary.mem0_oss block exists, so if you've already set a default auxiliary provider for other tasks you get mem0 OSS for free:

# ~/.hermes/config.yaml
auxiliary:
  default:                    # inherited by mem0_oss and all other aux tasks
    provider: auto
    model: us.anthropic.claude-haiku-4-5-20251001-v1:0

  # Optional — override just for mem0_oss:
  mem0_oss:
    provider: openrouter      # or openai, anthropic, ollama, aws_bedrock, custom
    model: openai/gpt-4o-mini
    # api_key: ...            # optional — falls back to provider's standard env var
    # base_url: ...           # optional — for custom/local endpoints

Supported provider values: openrouter, openai, anthropic, ollama, lmstudio, aws_bedrock (alias: bedrock), custom, auto. auto uses the same env-var detection order as zero-config.

Option B — AWS Bedrock

If you already use Hermes with Bedrock, no additional config is needed. The plugin reuses AWS_ACCESS_KEY_ID / AWS_SECRET_ACCESS_KEY / AWS_REGION.

LLM default: us.anthropic.claude-haiku-4-5-20251001-v1:0 Embedder default: amazon.titan-embed-text-v2:0 (1024-dim)

Option C — OpenAI

# If OPENAI_API_KEY is already set, nothing more is needed.
# Override model/embedder explicitly if desired:
export MEM0_OSS_LLM_MODEL=gpt-4o-mini
export MEM0_OSS_EMBEDDER_MODEL=text-embedding-3-small
export MEM0_OSS_EMBEDDER_DIMS=1536

Option D — Ollama (fully local, no API key)

export MEM0_OSS_LLM_PROVIDER=ollama
export MEM0_OSS_LLM_MODEL=llama3.2
export MEM0_OSS_EMBEDDER_PROVIDER=ollama
export MEM0_OSS_EMBEDDER_MODEL=nomic-embed-text
export MEM0_OSS_EMBEDDER_DIMS=768

3. Activate

# ~/.hermes/config.yaml
memory:
  provider: mem0_oss

Or use the interactive setup wizard:

hermes memory setup    # select "mem0_oss"

Storage

Path	Contents
$HERMES_HOME/mem0_oss/qdrant/	Qdrant vector store (all memories)
$HERMES_HOME/mem0_oss/history.db	mem0 history SQLite database

Override with MEM0_OSS_VECTOR_STORE_PATH and MEM0_OSS_HISTORY_DB_PATH.

Non-secret settings can also be persisted to $HERMES_HOME/mem0_oss.json by the setup wizard (via save_config), or written manually — see All configuration options.

Agent tools

Tool	Description
mem0_oss_search	Semantic search over stored memories
mem0_oss_add	Store a fact, preference, or context explicitly

Facts are extracted and stored automatically on every conversation turn via sync_turn — no explicit save call needed.

Writes via the built-in memory tool are also mirrored automatically into mem0 via on_memory_write. To explicitly save something mid-session, use mem0_oss_add (or the built-in memory tool — both propagate to mem0).

Concurrent access (WebUI + gateway)

The plugin uses embedded Qdrant which normally allows only one process at a time. To avoid conflicts when both the WebUI and the gateway run on the same host, the plugin creates a fresh Memory instance per operation and releases the Qdrant lock immediately after each call. If a brief overlap occurs the operation is skipped gracefully (logged at DEBUG, not counted as a failure) rather than raising an error.

All configuration options

Environment variables

Env var	Default	Description
MEM0_OSS_LLM_PROVIDER	auto-detected	LLM provider (openrouter, openai, anthropic, ollama, aws_bedrock, …)
MEM0_OSS_LLM_MODEL	provider default	LLM model id
MEM0_OSS_EMBEDDER_PROVIDER	mirrors LLM provider	Embedder provider
MEM0_OSS_EMBEDDER_MODEL	provider default	Embedder model id
MEM0_OSS_EMBEDDER_DIMS	provider default	Embedding dimensions
MEM0_OSS_COLLECTION	hermes	Qdrant collection name
MEM0_OSS_USER_ID	hermes-user	Memory namespace
MEM0_OSS_TOP_K	10	Default search result count
MEM0_OSS_VECTOR_STORE_PATH	$HERMES_HOME/mem0_oss/qdrant	On-disk Qdrant path
MEM0_OSS_HISTORY_DB_PATH	$HERMES_HOME/mem0_oss/history.db	SQLite history path
MEM0_OSS_API_KEY	(auto-detected from provider env var)	Explicit API key for the LLM backend
MEM0_OSS_OPENAI_BASE_URL	(none)	OpenAI-compatible endpoint override

config.yaml (auxiliary.mem0_oss / auxiliary.default)

auxiliary.mem0_oss keys take precedence; any key not set there falls back to auxiliary.default (which is also used by compression, vision, and other aux tasks).

Key	Description
provider	Hermes provider name (see auto-detect order above)
model	LLM model id
base_url	Custom OpenAI-compatible endpoint
api_key	Explicit API key (takes precedence over env vars)

Key resolution priority

1. MEM0_OSS_API_KEY env var
2. auxiliary.mem0_oss.api_key in config.yaml
3. Provider's standard env var (OPENROUTER_API_KEY, ANTHROPIC_API_KEY, OPENAI_API_KEY, …) resolved via the Hermes provider registry
4. AWS credentials from environment (for Bedrock)

Or put non-secret settings in $HERMES_HOME/mem0_oss.json (keys are the env-var names without the MEM0_OSS_ prefix, in snake_case):

{
  "llm_provider": "aws_bedrock",
  "llm_model": "us.anthropic.claude-haiku-4-5-20251001-v1:0",
  "embedder_provider": "aws_bedrock",
  "embedder_model": "amazon.titan-embed-text-v2:0",
  "embedder_dims": 1024,
  "collection": "hermes",
  "user_id": "hermes-user",
  "top_k": 10
}