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justcrawl.io

Claude Desktop

Add justcrawl as an MCP server in Claude Desktop. Once wired, you can ask Claude things like "submit a scrape for https://walmart.com/p/abc and tell me when it's done" — and it will use the jc_jobs_* tools directly.

Prerequisites

Section titled “Prerequisites”
  • Claude Desktop installed (download)
  • Node.js 20 or newer on PATH (node --version to check)
  • A justcrawl API key — Settings → API Keys in the dashboard. Starts with sr_live_.

Configure

Section titled “Configure”

  1. Open the Claude Desktop config file. Claude Desktop reads claude_desktop_config.json on every launch.

    | OS | Path | |----|------| | macOS | ~/Library/Application Support/Claude/claude_desktop_config.json | | Windows | %APPDATA%\Claude\claude_desktop_config.json |

    Claude Desktop officially ships for macOS and Windows. If the file doesn't exist, create it with {} as the contents. Easiest path: open Claude Desktop → Settings → Developer → Edit Config. Claude creates the file on first edit.

  2. Add the justcrawl MCP server block. Merge this into the file (preserve any other servers you already have):

    {
      "mcpServers": {
        "justcrawl": {
          "command": "npx",
          "args": ["-y", "@justcrawl/mcp-server"],
          "env": {
            "JUSTCRAWL_API_KEY": "sr_live_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
          }
        }
      }
    }

    Replace sr_live_xxxxx… with your real key. Do not commit this file to a public repo — the key is plaintext.

  3. Restart Claude Desktop. Fully quit (⌘Q on macOS, right-click → Quit on Windows / Linux) and reopen. MCP servers are spawned only on cold start.

  4. Confirm it's wired. Open Settings → Developer → MCP Servers. You should see justcrawl listed with a green status dot. Click the row to see the discovered tools — you should see jc_jobs_submit, jc_workflows_list, etc.

First prompt to try

Section titled “First prompt to try”

In any conversation:

List my justcrawl workflows.

Claude calls jc_workflows_list() and renders the result. If you see the workflows from your dashboard, you're done.

Troubleshooting

Section titled “Troubleshooting”

Red status dot in Settings → Developer → MCP Servers. Click the row to see the stderr log. The most common failures:

  • JUSTCRAWL_API_KEY is required — the env.JUSTCRAWL_API_KEY field is missing or empty. Re-check step 2.
  • command not found: npx — Node.js isn't on the PATH Claude Desktop sees. On macOS, install Node via the official installer (not nvm) so it lands in /usr/local/bin, which Claude Desktop searches.
  • 401 unauthorized — the API key is malformed or revoked. Generate a fresh one in the dashboard.

No tools show up after a green dot. The server started but no tools registered. Restart Claude Desktop one more time; if it persists, file an issue with the stderr log.

Stderr shows npm error 404 Not Found - GET https://registry.npmjs.org/@justcrawl%2Fmcp-server. The package isn't published yet (Phase 3). Your config is correct — restart Claude Desktop after the package lands and the same config will spawn the real server.

Section titled “Related”