Get your Cursor prototype reviewed, right on the page.
You built it fast in Cursor. Crux puts a toolbar on the running prototype, so your team can comment on any part, approve it, and see the research behind it.
Add Crux to your Cursor prototype
Click Add to Cursor, then paste one prompt into Cursor’s agent.
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Start free
Create a Crux account. It comes with a project for your prototype.
Start free - 2
Paste it into Cursor
Click Add to Cursor, then paste one prompt into Cursor’s agent. Cursor asks you to sign in to Crux the first time, then adds the connector.
Add to CursorThen ask Cursor’s agentInstall the Crux connector on this prototype, for my Crux project: find it with listing_projects on the crux MCP server, and ask me which one if there are several. Call prototype_plan on the crux MCP server first and follow its steps. If this folder has no prototype yet, build it from the plan, then install. If it has one, keep it as it is and link it to the plan. Either way finish with install_proof and make every change it lists, committed so deploys carry it. If the crux tools are not available, tell me to run /mcp, pick crux and sign in, then carry on.
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Review on the prototype
Reload the prototype and sign in on the Crux button at the bottom left. Click Inspect, then any part of the page, to comment on it or approve it.
On the prototype
The Crux connector adds one toolbar to any prototype.
See why
Click a part of the page to see the finding and the quotes behind it.
Comment
Talk it through on the component, with labels, @mentions and replies.
Approve
Sign off UX, UI, functionality and content, page by page and piece by piece.
Questions
- Where does Crux show up in Cursor?
- In Cursor’s settings, with your other MCP servers, named crux. The agent uses it when you paste the prompt.
- What does Crux change in my Cursor prototype?
- It adds a small tag to each page and component, so a comment stays on the part it is about, and one script that loads the toolbar. Cursor makes the changes in your code, where you can read them before you publish.
- Do my reviewers need Cursor?
- No. They open the prototype’s link in any browser, on a computer or a phone, and sign in on the Crux button. Reviewers, approvers and viewers take part free.
- Is it free?
- The connector is on every plan, Free included, so you can inspect, comment and approve on your own prototype at no cost. Inviting other people starts with Starter, at $29 a month.
- What happens when the prototype changes?
- Crux follows it. When you open the prototype, Crux picks up new and changed pages and components. Comments and approvals stay on the part they were made on, because each part has its own id in the code.
More ways in
By the tool you build in
By what you need done
- Client sign-offYour client approves each page and part where they see it.
- Prototype feedbackEvery comment sits on the part of the page it is about.
- Share with stakeholdersInvite people by email, each with a role.
- Design rationaleEach part of the page shows the finding and quotes behind it.
- Design reviewWalk the running prototype together, page by page.
Build anywhere.Think in Crux.
Evidence behind every decision, in every tool you build with.