Acheron

Shared persistent memory across Claude Chat, Code, and Cowork.

  ┌───────────┐     ┌───────────┐     ┌───────────┐
  │   Chat    │     │   Code    │     │  Cowork   │
  └─────┬─────┘     └─────┬─────┘     └─────┬─────┘
        │                 │                  │
        └────────┬────────┴────────┬─────────┘
                 │                 │
           ┌─────▼─────────────────▼─────┐
           │        Acheron MCP          │
           │  ┌───────────────────────┐  │
           │  │  ~/.acheron/bridge.db │  │
           │  └───────────────────────┘  │
           └─────────────────────────────┘
                  Local · No cloud

Save a decision in Chat. Retrieve it in Cowork. Search for it from Code. All local, all offline, zero configuration.

Install

claude mcp add acheron -- npx -y acheron-mcp-server

Or add to Claude Desktop config (Settings > Developer > Edit Config):

{
  "mcpServers": {
    "acheron": {
      "command": "npx",
      "args": ["-y", "acheron-mcp-server"]
    }
  }
}

Requires Node.js 20+. Native build tools may be needed for better-sqlite3 (details).

Usage

Just talk naturally. Acheron's tool descriptions are written so Claude uses them automatically.

Save context — say "remember this", "save this decision", "note that we chose X":

"Remember: we're using Next.js App Router for the acme-site project."

Search context — say "what did I decide about...", "find my notes on...":

"What did we decide about the authentication approach?"

Browse context — say "show me my preferences", "list all decisions for this project":

"Show me everything saved for acme-site."

How it works

Acheron is an MCP server. It stores context in a local SQLite database (~/.acheron/bridge.db) with full-text search. No cloud, no network calls, no telemetry. Data never leaves your machine.

Six tools, all prefixed bridge_:

| Tool | Purpose | |------|---------| | bridge_save_context | Remember decisions, preferences, insights, notes | | bridge_get_context | Retrieve full details of a saved context | | bridge_search_context | Full-text search across all saved contexts | | bridge_list_contexts | Browse and filter by project, surface, type, tags | | bridge_delete_context | Forget a saved context | | bridge_status | Overview of what's stored |

Troubleshooting

better-sqlite3 install fails? You need native build tools:

• macOS: xcode-select --install
• Linux: sudo apt install build-essential
• Windows: Visual Studio Build Tools

Database issues? Delete ~/.acheron/bridge.db — Acheron recreates it on next start.

License

MIT