Connects stdio MCP clients (Claude Desktop, Cursor, VS Code, and any client you configure with npx) to the local MCP server inside the Jam SQL Studio desktop app. Your AI tool can then list your saved connections and query SQL Server, PostgreSQL, MySQL/MariaDB, Oracle and SQLite under the permission level you set in the app.

The package forwards MCP messages between the client's stdin/stdout and the app's http://127.0.0.1:<port>/mcp endpoint. It finds the endpoint and the token on its own, the same way the jam-sql CLI does, so the client configuration contains no port and no token.

Full documentation: https://jamsql.com/docs/ai-integrations-mcp/#stdio-bridge

Requirements

Jam SQL Studio running, with Settings → AI Integrations → Enable MCP server turned on.
Paired once with jam-sql pair (the jam-sql CLI ships with the app and is installed on your PATH). Pairing stores the token in ~/.jamsql/credentials.
Node.js 18 or newer, with npx available.

Setup

Claude Desktop

Edit claude_desktop_config.json (macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\):

{
  "mcpServers": {
    "jam-sql": {
      "command": "npx",
      "args": ["-y", "@jamsql/mcp"]
    }
  }
}

Quit and reopen Claude Desktop.

Cursor

~/.cursor/mcp.json (all projects) or .cursor/mcp.json (one project):

{
  "mcpServers": {
    "jam-sql": {
      "command": "npx",
      "args": ["-y", "@jamsql/mcp"]
    }
  }
}

VS Code

.vscode/mcp.json:

{
  "servers": {
    "jam-sql": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@jamsql/mcp"]
    }
  }
}

Cursor and VS Code can also connect to the app's HTTP endpoint directly. The npx entry above needs no endpoint or token in the file and keeps working when the app's port changes.

Without `jam-sql pair`

Set the endpoint and the token from Settings → AI Integrations in the client's env block instead:

{
  "mcpServers": {
    "jam-sql": {
      "command": "npx",
      "args": ["-y", "@jamsql/mcp"],
      "env": {
        "JAMSQL_MCP_URL": "http://127.0.0.1:14507/mcp",
        "JAMSQL_MCP_TOKEN": "YOUR_TOKEN_HERE"
      }
    }
  }
}

Variable	Default
`JAMSQL_MCP_URL`	Read from `~/.jamsql/mcp-discovery.json`, which the app writes on start
`JAMSQL_MCP_TOKEN`	Read from `~/.jamsql/credentials`, which `jam-sql pair` writes
`JAMSQL_MCP_DEBUG`	Set to `1` to log each forwarded method name to stderr

The jam-sql CLI's variable names JAM_SQL_MCP_ENDPOINT and JAM_SQL_MCP_TOKEN are accepted too.

What happens when the app restarts

The app's MCP sessions end when the app restarts or its MCP server is switched off and on. The bridge notices, opens a new session with the client's original initialize parameters and retries the request, so the client keeps working without a restart. If the app comes back on a different port, the bridge reads the new port from the discovery file. A request that already reached the app is never sent twice; if its answer is lost, the client gets an error instead.

Troubleshooting

The bridge writes its messages to stderr, which your client keeps in its MCP log (Claude Desktop: ~/Library/Logs/Claude/ on macOS, %APPDATA%\Claude\logs\ on Windows). Requests that cannot be forwarded are answered with a JSON-RPC error carrying the same message. The token is never printed.

Message	What to do
Jam SQL Studio is not running	Start the app and keep it open.
Its MCP server is turned off	Settings → AI Integrations → Enable MCP server.
Not paired with Jam SQL Studio	Run `jam-sql pair`, or set `JAMSQL_MCP_TOKEN`.
Rejected the pairing token	The token was regenerated in the app. Run `jam-sql pair` again, or update `JAMSQL_MCP_TOKEN`.
Could not reach Jam SQL Studio's MCP server	Check `JAMSQL_MCP_URL`, or that the app's MCP server is enabled.

Check the bridge from a terminal:

npx -y @jamsql/mcp --version
echo '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{},"clientInfo":{"name":"terminal","version":"0"}}}' | npx -y @jamsql/mcp

The second command prints the app's initialize answer when everything is set up, or the error that says what is missing.

On Windows, if the client cannot start npx, use "command": "cmd" with "args": ["/c", "npx", "-y", "@jamsql/mcp"].