Five steps. Same steps for every IDE — just different config paths. Pick yours below.
New here? See what you'll actually see when you use it — the 7-step session walkthrough with real examples.
Optional — the config below uses npx, which fetches the server on each start, so a global install is not required.
npm i -g fetchsandbox-mcp@latest keeps you current automatically. For CI, or anywhere you want a reproducible build, pin the version instead — replace @latest with the release you want from npm, and update it deliberately.
~/.cursor/mcp.json{
"mcpServers": {
"fetchsandbox": {
"command": "/opt/homebrew/bin/npx",
"args": ["-y", "[email protected]"],
"env": { "FETCHSANDBOX_API_KEY": "fsk_your_key_here" }
}
}
}Get your account key from the keys page and replace the placeholder privately. Loading the tools confirms the connection; verification calls also need authentication. Keep this key out of chat and source control.
Cursor: finish these setup steps
The example above is for Homebrew on Apple Silicon Mac. Run command -v npx in your Mac or Linux terminal and use the full path it returns. On Windows, use where.exe npx and your installed Node.js executable path. Cursor may not inherit your Terminal’s PATH.
For Homebrew on Apple Silicon, that is commonly "command": "/opt/homebrew/bin/npx". Use your own result if it differs.
Use one FetchSandbox entry in ~/.cursor/mcp.json. Check for a second entry in your project’s .cursor/mcp.json so an older version or key does not confuse setup. Fully quit and reopen Cursor after saving, then confirm the server is connected. Tools loading and authenticated verification are separate checks.
The tested version is [email protected]. Replace fsk_your_key_here with your real account key from the keys page. Use the raw key, without a Bearer prefix. The example key cannot authenticate.
Save the config, then quit Cursor entirely and reopen it. Reloading the window alone may keep the old MCP process.
Open Cursor’s MCP settings and enable fetchsandbox if it is disabled. Confirm its tools are listed before asking it to validate the app.
In Cursor's MCP Servers panel, you should see a green dot next to fetchsandbox and its tools listed.
./fetchsandbox help me integrate stripe in my appThe ./fetchsandbox prefix dispatches to the brain — it matches your symptom to the right workflow + scenario, surfaces audit items, and returns a public receipt URL as proof. Variant prefixes also accepted: /fetchsandbox, @fetchsandbox, fs:.
./fetchsandbox validate my stripe integrationNothing to install. Add FetchSandbox as a custom MCP server and paste a key from /keys.
https://fetchsandbox.com/mcp/v1Choose Bearer token or API key for authentication and paste your key. Picking None returns 401 — the connector will look connected and every tool call will fail.
Describe the change and the rule your team needs to trust. Ask the agent what the current engine can measure. If your use case needs different controls or signals, let’s build the verification around your system.
Different use case? Talk to us.Most common cause on Cursor: the MCP server wasn't enabled after restart. Go back to step 4 and toggle fetchsandbox ON in Settings → MCP Servers.
The IDE didn't load the skill files. For Cursor + Claude Code, install the skills bundle:
curl -sL https://fetchsandbox.com/skills/install.sh | bashDelete .fetchsandbox/ in your project and re-run the trigger phrase. State resets clean.
Requires Node 18+. Check with node --version. If older, upgrade via nvm.
If this guide didn't get you there, DM @fetchsandbox on X with a screenshot of where you got stuck. We usually reply within a few hours and add the gotcha to this page so the next person doesn't hit it.