Connecting a local server

This guide follows the same structure as the stitched docs article and focuses on a reliable local setup.

Prerequisites

• Jumper extension installed.
• Node.js 18+ available locally.
• A reachable MCP endpoint such as ws://localhost:8080/mcp.

1. Create a local config

Create jumper.config.json:

{
  "server": {
    "port": 8080,
    "host": "localhost",
    "cors": true
  },
  "bridge": {
    "token": "env(JUMPER_API_TOKEN)",
    "logLevel": "debug"
  },
  "mappings": [
    {
      "mcp_param": "revenue_metric",
      "selector": "#revenue .value",
      "extract": "text"
    }
  ]
}

2. Start local bridge process

jumper start --config ./jumper.config.json

Expected startup signals:

• Service bound to configured port.
• MCP handshake endpoint reachable.
• Extension status indicates active bridge.

3. Validate a first extraction

1. Open the target dashboard tab.
2. Select one mapped element.
3. Confirm payload appears in console logs.

Example payload:

{
  "mcp_action": "inject_data",
  "payload": {
    "key": "revenue_metric",
    "value": 45289.0,
    "type": "currency"
  },
  "status": "success"
}

4. Hardening checks

• Ensure port is not occupied by another service.
• Keep token in environment variables, not plain text files.
• Fail closed when selectors return no matches.

Next

• Explore reusable templates in MCP registry.
• Use Console playground for iterative selector and payload debugging.