LanceDB Hybrid Search Memory Plugin

LanceDB long-term memory plugin with BM25 + vector hybrid search (RRF or linear reranking).

This skill packages a drop-in OpenClaw memory plugin that adds hybrid search to LanceDB memory:

• Vector search (semantic)
• BM25 full-text search (exact terms)
• Configurable reranking:
  • rrf (Reciprocal Rank Fusion, recommended)
  • linear (weighted combination)

It is based on (and credits) OpenClaw PR openclaw/openclaw#7636.

What you get

A local plugin (extension) located at:

• plugin/ → overrides the built-in plugin id memory-lancedb (adds hybrid search)

Once enabled, it provides the same tools as the bundled LanceDB memory plugin:

• memory_store
• memory_recall
• memory_forget

…but memory_recall/auto-recall/forget now use hybrid search when enabled.

Install / Enable

1. Ensure the skill folder exists (ClawHub install puts it under your workspace):

• ~/.openclaw/workspace/skills/memory-lancedb-hybrid/plugin

2. Install the plugin dependencies (once):

bash

cd ~/.openclaw/workspace/skills/memory-lancedb-hybrid/plugin
npm install --omit=dev

3. Add the plugin to OpenClaw’s plugin load paths.

This plugin keeps the id memory-lancedb, so it will override the bundled memory-lancedb extension when discovered via plugins.load.paths (higher precedence than bundled).

Edit ~/.openclaw/openclaw.json:

json5

{
  plugins: {
    load: {
      // Point at the plugin directory inside this skill
      paths: ["~/.openclaw/workspace/skills/memory-lancedb-hybrid/plugin"]
    },

    // Ensure the memory slot points at LanceDB memory
    slots: {
      memory: "memory-lancedb"
    },

    // Configure LanceDB memory (this override adds the `hybrid` config block)
    entries: {
      "memory-lancedb": {
        enabled: true,
        config: {
          embedding: {
            apiKey: "${OPENAI_API_KEY}",
            model: "text-embedding-3-small"
          },

          // Optional
          dbPath: "~/.openclaw/memory/lancedb",

          // Optional
          autoCapture: true,
          autoRecall: true,

          // Hybrid search options
          hybrid: {
            enabled: true,
            reranker: "rrf"

            // If using reranker: "linear", you can also set:
            // vectorWeight: 0.7,
            // textWeight: 0.3,
          }
        }
      }
    }
  }
}

4. Restart the Gateway.

Hybrid search needs an FTS index on the text column; the plugin will attempt to create it automatically. If FTS setup fails for any reason, the plugin logs a debug message and falls back to vector-only search.

Config reference

All config lives under plugins.entries.memory-lancedb.config.

• hybrid.enabled (boolean, default true)
• hybrid.reranker (rrf | linear, default rrf)
• hybrid.vectorWeight (number 0–1, default 0.7, only used for linear)
• hybrid.textWeight (number 0–1, default 0.3, only used for linear)

Notes / troubleshooting

• This plugin does not modify OpenClaw’s install on disk; it overrides the bundled memory-lancedb at runtime (remove plugins.load.paths to revert).
• If you already have LanceDB memory data on disk, you can keep using the same dbPath.
• If you see no hybrid effect, make sure hybrid.enabled is true and that the FTS index was created (check Gateway logs).

Files

• plugin/index.ts – plugin implementation (hybrid search)
• plugin/config.ts – config parsing + UI hints
• plugin/openclaw.plugin.json – manifest + JSON Schema (used for strict config validation)