Most connection problems come down to a sign-in that did not finish, a missing key, the wrong project, or a transport mismatch. Work through the issue that matches your symptom.

For the shared endpoint, signing in, and keys, see Connect overview.

The server does not appear

The MCP server is not listed, or your tool shows no UI Rules tools.

Confirm the server config was saved in the right place for your tool, then fully restart the tool so it reloads its MCP servers. Some tools load their servers only when a chat starts, so start a new chat and ask "Is UI Rules connected?" again.
If you connected by signing in, make sure you clicked Authorize on the UI Rules page. If the page says the authorization link is missing or has expired, start the connection again from your tool.
Check that the URL is exactly https://mcp.uirules.com/mcp, with no extra spaces or trailing characters.
If your tool lists MCP servers with a status, look for a connection error there. A failed start usually points to an unreachable URL or a header the tool did not send.

Auth or 401 errors

A 401 Unauthorized means the key the tool sends is missing, malformed, or no longer valid.

Confirm the key is set

If you pasted a key, make sure it is present and not empty in your tool config. The header names are in Connect overview.

Check the key is still active

A key stops working when it is revoked, when it expires, and when the person who created it leaves the organization. Check its status on the brand's API keys page.

A key's full value is shown only once, so a truncated or lost key cannot be copied again. Sign in again from your tool, or create a new key from Connect in the workspace top bar and paste it.

Never paste a real key into a shared file or screenshot. If a key may have leaked, revoke it from the API keys page.

Wrong scope (brand vs project)

The tool connects, but the served rules and tokens are not what you expected.

Each connection belongs to one project, and that project resolves the brand ruleset plus its own overrides. If a project has overrides, the tool sees the overridden values, not the raw brand.

Open the project and check its Overrides list. An empty list means it serves the brand untouched; anything in it changes a token, a rule, or what is visible for that project.
Review the project's effective (resolved) view to see exactly what the tool reads.
To follow a different effective view, connect again and select the project whose resolved view you want, or use that project's key.

The tool wants a command, not a URL

UI Rules is a remote server over HTTP. There is no local process to install and no command to run, so a tool that only launches local MCP servers cannot connect directly. Every tool in the Connect overview takes a URL, then signs in or sends a key as a header.

Nothing is served

The tool connects and authenticates, but no styles or rules come through.

A brand new brand starts on the default theme with no authored rules yet. Until you configure it, there is little for the tool to read.

Check the setup guide on the brand overview. If its Import your brand styles step is still open, your brand may still have the default theme.
Import your styles from Figma, a website, a pasted CSS theme, or a preset code. See Importing styles.
Add at least one rule group so the tool has guidance to serve. Components and blocks must also be switched on to appear in the component vocabulary; a switched-off entry is held back from delivery.

After you add styles or rules, you do not need to reconnect. The tool reads the current brand on its next request.

The agent says a tool was renamed, or is out of date

The agent reports an error like "list_rule_areas was renamed to get_rules_index", or says its instructions name a tool that is not in the list.

The tool names changed and something you pasted still uses the old ones. The server does not answer to old names; it tells the agent the new one and asks it to let you know.

Check any custom instruction you saved in the tool itself, such as v0's Instructions or Lovable's Workspace knowledge, and paste the current text from that tool's guide again.
For the full list of current names and what each replaced, see the MCP tools reference.

Calls stop with "Plan limit reached"

Your organization has used this month's MCP calls. Connected tools stop until the meter resets, and a call refused over the limit still counts. See Usage for where you stand and when it resets, and Plans for the limit on each tier.

A 429 with "Rate limit exceeded" is different: that is the per-minute limit, and it clears on its own. Wait for the retry-after and try again.

Connect troubleshooting