Crate narwhal_mcp 

Model Context Protocol (MCP) server for narwhal.

Exposes narwhal’s configured database connections to AI agents (Claude Desktop, Cursor, Continue, Aider, …) over the JSON-RPC 2.0 stdio transport defined by the MCP spec.

Quick start

use std::sync::Arc;
use narwhal_config::{ConfigPaths, ConnectionsFile, KeyringStore, DynCredentialStore};
use narwhal_mcp::{DriverRegistry, McpServer, ServerContext};

let paths = ConfigPaths::discover()?;
let connections = ConnectionsFile::load(&paths.connections_file())?;
let drivers = Arc::new(DriverRegistry::with_defaults());
let credentials: Arc<dyn DynCredentialStore> = Arc::new(KeyringStore::new());
let ctx = ServerContext::new(drivers, Arc::new(connections), credentials);
McpServer::new(ctx).serve_stdio().await?;

Wire-up for Claude Desktop

// ~/.config/Claude/claude_desktop_config.json
{
  "mcpServers": {
    "narwhal": {
      "command": "narwhal",
      "args": ["mcp"]
    }
  }
}

Tool surface (v0)

• tools::ListConnectionsTool — metadata only, no IO.
• tools::DescribeSchemaTool — opens a short-lived connection.

run_query / explain_query land in v0.2 once we’ve validated the read-only enforcement story.

Re-exports

pub use context::ServerContext;

pub use error::McpError;

pub use server::McpServer;

pub use workspace::Workspace;

pub use workspace::WorkspaceError;

pub use workspace::WorkspaceFile;

Modules

context

Shared, read-only context handed to every tool invocation.

error

Error types for the MCP server.

json_value

Convert narwhal_core::Value into the JSON shape an AI agent expects.

protocol

JSON-RPC 2.0 + Model Context Protocol message types.

registry

server

Stdio-based MCP server loop.

tools

Tool registry and the Tool trait every executable command implements.

workspace

Workspace discovery — .narwhal/workspace.toml.

Structs

DriverRegistry