---
sidebar_position: 4
title: "Memory Providers"
description: "External memory provider plugins — Honcho, OpenViking, Mem0, Hindsight, Holographic, RetainDB, ByteRover"
---

# Memory Providers

Hermes Agent ships with 7 external memory provider plugins that give the agent persistent, cross-session knowledge beyond the built-in MEMORY.md and USER.md. Only **one** external provider can be active at a time — the built-in memory is always active alongside it.

## Quick Start

```bash
hermes memory setup      # interactive picker + configuration
hermes memory status     # check what's active
hermes memory off        # disable external provider
```

Or set manually in `~/.hermes/config.yaml`:

```yaml
memory:
  provider: openviking   # or honcho, mem0, hindsight, holographic, retaindb, byterover
```

## How It Works

When a memory provider is active, Hermes automatically:

1. **Injects provider context** into the system prompt (what the provider knows)
2. **Prefetches relevant memories** before each turn (background, non-blocking)
3. **Syncs conversation turns** to the provider after each response
4. **Extracts memories on session end** (for providers that support it)
5. **Mirrors built-in memory writes** to the external provider
6. **Adds provider-specific tools** so the agent can search, store, and manage memories

The built-in memory (MEMORY.md / USER.md) continues to work exactly as before. The external provider is additive.

## Available Providers

### Honcho

AI-native cross-session user modeling with dialectic Q&A, semantic search, and persistent conclusions.

| | |
|---|---|
| **Best for** | Multi-agent systems with cross-session context, user-agent alignment |
| **Requires** | `pip install honcho-ai` + [API key](https://app.honcho.dev) or self-hosted instance |
| **Data storage** | Honcho Cloud or self-hosted |
| **Cost** | Honcho pricing (cloud) / free (self-hosted) |

**Tools:** `honcho_profile` (peer card), `honcho_search` (semantic search), `honcho_context` (LLM-synthesized), `honcho_conclude` (store facts)

**Setup Wizard:**
```bash
hermes honcho setup        # (legacy command) 
# or
hermes memory setup        # select "honcho"
```

**Config:** `$HERMES_HOME/honcho.json` (profile-local) or `~/.honcho/config.json` (global). Resolution order: `$HERMES_HOME/honcho.json` > `~/.hermes/honcho.json` > `~/.honcho/config.json`. See the [config reference](https://github.com/hermes-ai/hermes-agent/blob/main/plugins/memory/honcho/README.md) and the [Honcho integration guide](https://docs.honcho.dev/v3/guides/integrations/hermes).

<details>
<summary>Key config options</summary>

| Key | Default | Description |
|-----|---------|-------------|
| `apiKey` | -- | API key from [app.honcho.dev](https://app.honcho.dev) |
| `baseUrl` | -- | Base URL for self-hosted Honcho |
| `peerName` | -- | User peer identity |
| `aiPeer` | host key | AI peer identity (one per profile) |
| `workspace` | host key | Shared workspace ID |
| `recallMode` | `hybrid` | `hybrid` (auto-inject + tools), `context` (inject only), `tools` (tools only) |
| `observation` | all on | Per-peer `observeMe`/`observeOthers` booleans |
| `writeFrequency` | `async` | `async`, `turn`, `session`, or integer N |
| `sessionStrategy` | `per-directory` | `per-directory`, `per-repo`, `per-session`, `global` |
| `dialecticReasoningLevel` | `low` | `minimal`, `low`, `medium`, `high`, `max` |
| `dialecticDynamic` | `true` | Auto-bump reasoning by query length |
| `messageMaxChars` | `25000` | Max chars per message (chunked if exceeded) |

</details>

<details>
<summary>Minimal honcho.json (cloud)</summary>

```json
{
  "apiKey": "your-key-from-app.honcho.dev",
  "hosts": {
    "hermes": {
      "enabled": true,
      "aiPeer": "hermes",
      "peerName": "your-name",
      "workspace": "hermes"
    }
  }
}
```

</details>

<details>
<summary>Minimal honcho.json (self-hosted)</summary>

```json
{
  "baseUrl": "http://localhost:8000",
  "hosts": {
    "hermes": {
      "enabled": true,
      "aiPeer": "hermes",
      "peerName": "your-name",
      "workspace": "hermes"
    }
  }
}
```

</details>

:::tip Migrating from `hermes honcho`
If you previously used `hermes honcho setup`, your config and all server-side data are intact. Just re-enable through the setup wizard again or manually set `memory.provider: honcho` to reactivate via the new system.
:::

**Multi-agent / Profiles:**

Each Hermes profile gets its own Honcho AI peer while sharing the same workspace -- all profiles see the same user representation, but each agent builds its own identity and observations.

```bash
hermes profile create coder --clone   # creates honcho peer "coder", inherits config from default
```

What `--clone` does: creates a `hermes.coder` host block in `honcho.json` with `aiPeer: "coder"`, shared `workspace`, inherited `peerName`, `recallMode`, `writeFrequency`, `observation`, etc. The peer is eagerly created in Honcho so it exists before first message.

For profiles created before Honcho was set up:

```bash
hermes honcho sync   # scans all profiles, creates host blocks for any missing ones
```

This inherits settings from the default `hermes` host block and creates new AI peers for each profile. Idempotent -- skips profiles that already have a host block.

<details>
<summary>Full honcho.json example (multi-profile)</summary>

```json
{
  "apiKey": "your-key",
  "workspace": "hermes",
  "peerName": "eri",
  "hosts": {
    "hermes": {
      "enabled": true,
      "aiPeer": "hermes",
      "workspace": "hermes",
      "peerName": "eri",
      "recallMode": "hybrid",
      "writeFrequency": "async",
      "sessionStrategy": "per-directory",
      "observation": {
        "user": { "observeMe": true, "observeOthers": true },
        "ai": { "observeMe": true, "observeOthers": true }
      },
      "dialecticReasoningLevel": "low",
      "dialecticDynamic": true,
      "dialecticMaxChars": 600,
      "messageMaxChars": 25000,
      "saveMessages": true
    },
    "hermes.coder": {
      "enabled": true,
      "aiPeer": "coder",
      "workspace": "hermes",
      "peerName": "eri",
      "recallMode": "tools",
      "observation": {
        "user": { "observeMe": true, "observeOthers": false },
        "ai": { "observeMe": true, "observeOthers": true }
      }
    },
    "hermes.writer": {
      "enabled": true,
      "aiPeer": "writer",
      "workspace": "hermes",
      "peerName": "eri"
    }
  },
  "sessions": {
    "/home/user/myproject": "myproject-main"
  }
}
```

</details>

See the [config reference](https://github.com/hermes-ai/hermes-agent/blob/main/plugins/memory/honcho/README.md) and [Honcho integration guide](https://docs.honcho.dev/v3/guides/integrations/hermes).


---

### OpenViking

Context database by Volcengine (ByteDance) with filesystem-style knowledge hierarchy, tiered retrieval, and automatic memory extraction into 6 categories.

| | |
|---|---|
| **Best for** | Self-hosted knowledge management with structured browsing |
| **Requires** | `pip install openviking` + running server |
| **Data storage** | Self-hosted (local or cloud) |
| **Cost** | Free (open-source, AGPL-3.0) |

**Tools:** `viking_search` (semantic search), `viking_read` (tiered: abstract/overview/full), `viking_browse` (filesystem navigation), `viking_remember` (store facts), `viking_add_resource` (ingest URLs/docs)

**Setup:**
```bash
# Start the OpenViking server first
pip install openviking
openviking-server

# Then configure Hermes
hermes memory setup    # select "openviking"
# Or manually:
hermes config set memory.provider openviking
echo "OPENVIKING_ENDPOINT=http://localhost:1933" >> ~/.hermes/.env
```

**Key features:**
- Tiered context loading: L0 (~100 tokens) → L1 (~2k) → L2 (full)
- Automatic memory extraction on session commit (profile, preferences, entities, events, cases, patterns)
- `viking://` URI scheme for hierarchical knowledge browsing

---

### Mem0

Server-side LLM fact extraction with semantic search, reranking, and automatic deduplication.

| | |
|---|---|
| **Best for** | Hands-off memory management — Mem0 handles extraction automatically |
| **Requires** | `pip install mem0ai` + API key |
| **Data storage** | Mem0 Cloud |
| **Cost** | Mem0 pricing |

**Tools:** `mem0_profile` (all stored memories), `mem0_search` (semantic search + reranking), `mem0_conclude` (store verbatim facts)

**Setup:**
```bash
hermes memory setup    # select "mem0"
# Or manually:
hermes config set memory.provider mem0
echo "MEM0_API_KEY=your-key" >> ~/.hermes/.env
```

**Config:** `$HERMES_HOME/mem0.json`

| Key | Default | Description |
|-----|---------|-------------|
| `user_id` | `hermes-user` | User identifier |
| `agent_id` | `hermes` | Agent identifier |

---

### Hindsight

Long-term memory with knowledge graph, entity resolution, and multi-strategy retrieval. The `hindsight_reflect` tool provides cross-memory synthesis that no other provider offers.

| | |
|---|---|
| **Best for** | Knowledge graph-based recall with entity relationships |
| **Requires** | Cloud: `pip install hindsight-client` + API key. Local: `pip install hindsight` + LLM key |
| **Data storage** | Hindsight Cloud or local embedded PostgreSQL |
| **Cost** | Hindsight pricing (cloud) or free (local) |

**Tools:** `hindsight_retain` (store with entity extraction), `hindsight_recall` (multi-strategy search), `hindsight_reflect` (cross-memory synthesis)

**Setup:**
```bash
hermes memory setup    # select "hindsight"
# Or manually:
hermes config set memory.provider hindsight
echo "HINDSIGHT_API_KEY=your-key" >> ~/.hermes/.env
```

**Config:** `$HERMES_HOME/hindsight/config.json`

| Key | Default | Description |
|-----|---------|-------------|
| `mode` | `cloud` | `cloud` or `local` |
| `bank_id` | `hermes` | Memory bank identifier |
| `budget` | `mid` | Recall thoroughness: `low` / `mid` / `high` |

---

### Holographic

Local SQLite fact store with FTS5 full-text search, trust scoring, and HRR (Holographic Reduced Representations) for compositional algebraic queries.

| | |
|---|---|
| **Best for** | Local-only memory with advanced retrieval, no external dependencies |
| **Requires** | Nothing (SQLite is always available). NumPy optional for HRR algebra. |
| **Data storage** | Local SQLite |
| **Cost** | Free |

**Tools:** `fact_store` (9 actions: add, search, probe, related, reason, contradict, update, remove, list), `fact_feedback` (helpful/unhelpful rating that trains trust scores)

**Setup:**
```bash
hermes memory setup    # select "holographic"
# Or manually:
hermes config set memory.provider holographic
```

**Config:** `config.yaml` under `plugins.hermes-memory-store`

| Key | Default | Description |
|-----|---------|-------------|
| `db_path` | `$HERMES_HOME/memory_store.db` | SQLite database path |
| `auto_extract` | `false` | Auto-extract facts at session end |
| `default_trust` | `0.5` | Default trust score (0.0–1.0) |

**Unique capabilities:**
- `probe` — entity-specific algebraic recall (all facts about a person/thing)
- `reason` — compositional AND queries across multiple entities
- `contradict` — automated detection of conflicting facts
- Trust scoring with asymmetric feedback (+0.05 helpful / -0.10 unhelpful)

---

### RetainDB

Cloud memory API with hybrid search (Vector + BM25 + Reranking), 7 memory types, and delta compression.

| | |
|---|---|
| **Best for** | Teams already using RetainDB's infrastructure |
| **Requires** | RetainDB account + API key |
| **Data storage** | RetainDB Cloud |
| **Cost** | $20/month |

**Tools:** `retaindb_profile` (user profile), `retaindb_search` (semantic search), `retaindb_context` (task-relevant context), `retaindb_remember` (store with type + importance), `retaindb_forget` (delete memories)

**Setup:**
```bash
hermes memory setup    # select "retaindb"
# Or manually:
hermes config set memory.provider retaindb
echo "RETAINDB_API_KEY=your-key" >> ~/.hermes/.env
```

---

### ByteRover

Persistent memory via the `brv` CLI — hierarchical knowledge tree with tiered retrieval (fuzzy text → LLM-driven search). Local-first with optional cloud sync.

| | |
|---|---|
| **Best for** | Developers who want portable, local-first memory with a CLI |
| **Requires** | ByteRover CLI (`npm install -g byterover-cli` or [install script](https://byterover.dev)) |
| **Data storage** | Local (default) or ByteRover Cloud (optional sync) |
| **Cost** | Free (local) or ByteRover pricing (cloud) |

**Tools:** `brv_query` (search knowledge tree), `brv_curate` (store facts/decisions/patterns), `brv_status` (CLI version + tree stats)

**Setup:**
```bash
# Install the CLI first
curl -fsSL https://byterover.dev/install.sh | sh

# Then configure Hermes
hermes memory setup    # select "byterover"
# Or manually:
hermes config set memory.provider byterover
```

**Key features:**
- Automatic pre-compression extraction (saves insights before context compression discards them)
- Knowledge tree stored at `$HERMES_HOME/byterover/` (profile-scoped)
- SOC2 Type II certified cloud sync (optional)

---

## Provider Comparison

| Provider | Storage | Cost | Tools | Dependencies | Unique Feature |
|----------|---------|------|-------|-------------|----------------|
| **Honcho** | Cloud | Paid | 4 | `honcho-ai` | Dialectic user modeling |
| **OpenViking** | Self-hosted | Free | 5 | `openviking` + server | Filesystem hierarchy + tiered loading |
| **Mem0** | Cloud | Paid | 3 | `mem0ai` | Server-side LLM extraction |
| **Hindsight** | Cloud/Local | Free/Paid | 3 | `hindsight-client` | Knowledge graph + reflect synthesis |
| **Holographic** | Local | Free | 2 | None | HRR algebra + trust scoring |
| **RetainDB** | Cloud | $20/mo | 5 | `requests` | Delta compression |
| **ByteRover** | Local/Cloud | Free/Paid | 3 | `brv` CLI | Pre-compression extraction |

## Profile Isolation

Each provider's data is isolated per [profile](/docs/user-guide/profiles):

- **Local storage providers** (Holographic, ByteRover) use `$HERMES_HOME/` paths which differ per profile
- **Config file providers** (Honcho, Mem0, Hindsight) store config in `$HERMES_HOME/` so each profile has its own credentials
- **Cloud providers** (RetainDB) auto-derive profile-scoped project names
- **Env var providers** (OpenViking) are configured via each profile's `.env` file

## Building a Memory Provider

See the [Developer Guide: Memory Provider Plugins](/docs/developer-guide/memory-provider-plugin) for how to create your own.