Fix: Vibium MCP Server Not Connecting

To fix a Vibium MCP server that will not connect, verify the server is registered with claude mcp list, fully restart your AI client so it re-runs tool discovery, and confirm Chrome for Testing is installed with vibium install. Vibium ships a built-in MCP (Model Context Protocol) server inside its single Go binary, exposing 22 browser tools — browser_launch, browser_navigate, browser_click, browser_screenshot, and more — to AI clients like Claude Code, Cursor, and Gemini CLI. The single biggest reason it "won't connect" is that MCP tool discovery happens only at client startup: if you add or edit the Vibium server while the client is open, the change does not take effect until you start a fresh session. The other two recurring causes are a wrong command or path in the config, and Chrome for Testing not being downloaded yet so browser_launch fails after the server connects. Created by Jason Huggins, co-creator of Selenium and Appium, Vibium's MCP server is the same binary you run for Python and JS, so once it is registered and discovered, every AI tool call drives real Chrome. See the Vibium MCP in Claude Code guide for the full setup.

Why is the Vibium MCP server not connecting?

The most common cause is that your AI client never re-ran tool discovery. MCP clients connect to each configured server and list its tools on startup only — so if you added or modified the Vibium server while the client was running, it still has no idea Vibium exists. The fix is almost always to fully quit and reopen the client. The next most common causes are a typo in the command or binary path, and Chrome for Testing not being installed, which lets the server connect but makes browser actions fail.

How do I verify the Vibium MCP server is registered?

In Claude Code, list every configured MCP server and its health status:

claude mcp list

A healthy Vibium entry looks like this:

Checking MCP server health...
 
vibium: npx -y vibium mcp - ✓ Connected

If Vibium is missing from the list, add it and then restart the client:

claude mcp add vibium -- npx -y vibium mcp

After adding, run claude mcp list again to confirm it shows ✓ Connected. Remember that the new tools only appear in a brand-new session — an already-open client will not pick them up.

Why does the server connect but browser tools fail?

If claude mcp list shows Vibium connected but a request like "take a screenshot of example.com" fails at launch, Chrome for Testing is almost certainly not installed yet. The MCP server starts fine because it is just the Go binary, but browser_launch needs the bundled browser. Install it:

# For the published package
vibium install
 
# For a local clicker build
./clicker/bin/clicker install

Then start a fresh client session and retry. You can also smoke-test the server directly over stdin to confirm it responds before involving the AI client:

echo '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"capabilities":{}}}' | npx -y vibium mcp

A correct response includes "serverInfo":{"name":"vibium",...}, which proves the binary speaks MCP and the problem is downstream in the client config or the browser install.

How do I fix a wrong command or path?

If the server shows as failed rather than connected, the registered command is usually wrong — a bad binary path, a missing mcp subcommand, or npx not being on PATH. Remove and re-add the server with the correct command:

claude mcp remove vibium
claude mcp add vibium -- npx -y vibium mcp     # or an absolute path to your binary

For a locally built binary, use the absolute path so the client does not depend on the working directory:

claude mcp add vibium -- $HOME/Projects/vibium/clicker/bin/clicker mcp

Confirm the binary itself runs before blaming the client by calling npx -y vibium mcp --help (or ./clicker/bin/clicker mcp --help). If that errors, fix the install first.

Checklist when Vibium MCP will not connect

• Restart the AI client after any config change — discovery runs only on startup.
• Run claude mcp list to confirm the server is registered and shows ✓ Connected.
• Install Chrome for Testing with vibium install if the server connects but browser_launch fails.
• Use an absolute path for locally built binaries so the command never depends on the cwd.
• Smoke-test over stdin with an initialize message to isolate a binary problem from a client problem.

For setup in other clients and any options you are unsure about, see the Vibium MCP in Claude Code guide and the official docs at vibium.com.

Next steps

• Set up Vibium MCP in Claude Code
• Vibium MCP overview
• What is Vibium?
• Glossary of Vibium terms