Uplink

• You’re developing an MCP server and want to test it against a real agent before publishing.
• The server needs something only a specific machine can reach — a browser, a local database, an SSH key, a code editor.
• You want to run a private tool for yourself or your team without hosting it.

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Quick Start

# Point at an MCP server already running locally
smithery mcp add http://localhost:9090/mcp --id chrome

# Let the CLI spawn and manage a stdio MCP server
smithery mcp add --id chrome -- npx -y @chromedevtools/chrome-devtools-mcp

Uplink connected → my-app/chrome (status: connected)

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Call it like any other connection

smithery tool list chrome
smithery tool call chrome navigate '{"url": "https://smithery.ai"}'

import Smithery from '@smithery/api';
import { createConnection } from '@smithery/api/mcp';
import { createMCPClient } from '@ai-sdk/mcp';

const smithery = new Smithery();

const { transport } = await createConnection({
  client: smithery,
  namespace: 'my-app',
  connectionId: 'chrome',
});

const mcpClient = await createMCPClient({ transport });
const tools = await mcpClient.tools();

curl https://smithery.run/my-app/chrome/.tools \
  -H "Authorization: Bearer $SMITHERY_API_KEY"

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How it works

1. Registers a connection on your namespace marked as uplink-backed.
2. Opens a persistent WebSocket to Smithery scoped to that connection.
3. Connects to your local HTTP server, or spawns the command as a subprocess, and bridges JSON-RPC between the WebSocket and the local process.

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Connection lifecycle

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One tunnel per connection

smithery mcp add http://localhost:9090/mcp --id chrome --force

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Security

• Traffic is end-to-end TLS from Smithery to the CLI. The local MCP server speaks plain stdio or loopback HTTP to the CLI as it normally would.
• Uplink forwards arbitrary traffic to a process on the host machine. Only uplink servers you trust, and treat any trailing command as you would any other local executable.

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Limitations

• One tunnel per connection. See above.
• Availability follows the host. If the CLI is offline, the connection reports disconnected and calls fail fast. Uplink is a development and personal-automation primitive, not a hosting solution — publish your server to Smithery when you’re ready for production.
• Latency includes your network. Every request makes a round trip to the host machine.