@logicpearl/mcp

A Model Context Protocol (MCP) server that exposes LogicPearl — the deterministic decision primitive — to Claude Desktop, Cursor, and any other MCP-compatible host. One command installs it.

npx @logicpearl/mcp install

That writes the server entry into each host's MCP config with a timestamped backup. Relaunch the host, and every chat has three new tools.

Tools

| Tool | What it does | |---|---| | logicpearl_evaluate | Run a feature vector through the compiled artifact. Returns verdict, fired rules, counterfactual hints, latency, and a replayable bitmask. | | logicpearl_describe_artifact | Return the feature schema, allowed string codes, actions, rules, and an optional extraction-prompt template. | | logicpearl_list_rules | Enumerate every rule with id, action, label, features, and counterfactual hint. |

Every call is deterministic — same facts in, same bitmask out, every time.

Install

# Both Claude Desktop and Cursor at once
npx @logicpearl/mcp install

# Just one host
npx @logicpearl/mcp install --host claude
npx @logicpearl/mcp install --host cursor

# Preview the config diff without writing
npx @logicpearl/mcp install --dry-run

Existing config files are copied to <config>.<timestamp>.bak before any write.

Manual setup

If you use a host that isn't Claude Desktop or Cursor, add this to its mcp.json:

{
  "mcpServers": {
    "logicpearl": {
      "command": "npx",
      "args": ["-y", "@logicpearl/mcp", "start"]
    }
  }
}

Pass --artifact <url-or-path> after start to override the default artifact with your own.

Run the server directly

# Foreground, stdio transport — useful for testing with MCP Inspector
npx @logicpearl/mcp start

# Or plug into MCP Inspector
npx @modelcontextprotocol/inspector npx @logicpearl/mcp start

What ships

A default refund-eligibility artifact (8 features including a string-categorical, 5 learned rules, 8 KB Wasm). Pass --artifact to swap in your own compiled LogicPearl bundle.

Security posture (v1)

• stdio transport only — the host spawns the server as a child process
• No server-side auth (stdio already gates access via the host)
• No artifact-signature verification yet
• Artifact URLs must be publicly reachable or local paths

Fine for developer exploration, internal integration, and pilots. Needs hardening before multi-tenant production.

What's next

• @logicpearl/try — kick the tires on the engine without writing any integration code
• @logicpearl/browser — loadArtifact() + evaluate() in the browser or worker
• MCP docs | Source

License

MIT