Local stdio

Local stdio is the smallest trust boundary: the MCP client launches the compiled server and communicates over its standard input and output streams. No network listener is opened.

Local stdio configuration

{
  "mcpServers": {
    "simplelogin": {
      "command": "node",
      "args": ["/absolute/path/to/simplelogin-mcp/dist/index.js"],
      "env": {
        "TRANSPORT": "stdio",
        "SL_API_KEY": "sl-your-key-here"
      }
    }
  }
}

This JSON illustrates Claude Desktop's stdio shape; other clients use different configuration formats. Run pnpm install --filter simplelogin-mcp --frozen-lockfile && pnpm build first. Stdio does not use MCP_AUTH_TOKEN; keep the client config private because it contains your API key. Use the recipe for your MCP client.

Configure a client

1. Get and build the server. Clone the project if you do not already have a checkout, then build it:

   git clone https://github.com/enthouan/simplelogin-mcp.git
   cd simplelogin-mcp
   corepack enable
   pnpm install --filter simplelogin-mcp --frozen-lockfile
   pnpm build

2. Use an absolute entry path. Point the client at this checkout’s dist/index.js.

3. Set the transport and key. Create a dedicated key, then pass TRANSPORT=stdio and SL_API_KEY in the client process environment.

4. Restart the client. Reopen it so the process configuration is reloaded.

Keep the client configuration private

MCP_AUTH_TOKEN is not needed for stdio because there is no HTTP endpoint. The client config still contains SL_API_KEY, which grants full account control. Never commit or share it.

The server writes diagnostics to stderr because stdout is reserved for MCP messages.

Verify through MCP

After the client reports that simplelogin-mcp is connected and its tools are discovered, verify a read-only account call.

Verify it works

After the client discovers the server, use this low-data, read-only check:

Read-only verification prompt

Can you show me my SimpleLogin account usage?

Expected result

The expected tool is account_get_stats. Confirm that it is marked read-only before approving it. It takes no arguments and returns aggregate account counts without changing SimpleLogin. Those counts still pass through the client and its configured model.

Use Operations when upgrading or rolling back the source checkout used by this client configuration.