server in cursor shows it as connected but no tools working

[ARCIST-AI]

I can see you guys are trying to work it out. Has there been any solutions yet? @maceip @michiosw

[michiosw]

Hey @ARCIST-AI, could you please share details of your current setup? We have existing documentation here: #16, which we'll soon expand with examples for troubleshooting common issues.

For now, please review the document and provide your specific configuration so we can reproduce and investigate the error you're encountering. On our end, the server runs correctly both natively and within a Docker container.

Happy to assist further if you have any questions or run into issues—just let us know!

[ARCIST-AI]

Hey @ARCIST-AI, could you please share details of your current setup? We have existing documentation here: #16, which we'll soon expand with examples for troubleshooting common issues.

For now, please review the document and provide your specific configuration so we can reproduce and investigate the error you're encountering. On our end, the server runs correctly both natively and within a Docker container.

Happy to assist further if you have any questions or run into issues—just let us know!

@michiosw Here it is:

System Information

• OS: macOS Sequoia 15.3.2 (Apple M4 Pro)
• RAM: 64 GB
• Cursor Version: Latest (with MCP support)
• browser-use-mcp-server: Cloned from GitHub main branch

Current Setup

• Server configuration in .cursor/mcp.json:

  {
    "mcpServers": {
      "browser-use-mcp-server": {
        "url": "http://localhost:8000/sse"
      }
    }
  }

• The server appears connected in Cursor (green status indicator)

• When attempting to use browser tools, they fail with: "Failed to take screenshot: fetch failed"

Issue Analysis

I believe the issue may be related to the MCP protocol transport changes (PR #206 in the main MCP specification). This PR removes the /sse endpoint and replaces it with a new "Streamable HTTP transport" model.

The current browser-use-mcp-server uses the older SSE transport method, as stated in your README: "browser-use MCP Server with SSE transport". However, Cursor may have been updated to use the newer HTTP Streamable protocol, causing incompatibility.

Attempted Solutions

• Verified server configuration matches README recommendations
• Confirmed server connection appears active in Cursor
• Attempted browser commands, which show "fetch failed" errors

Any guidance on resolving this compatibility issue would be greatly appreciated. Happy to provide any additional information needed.

[michiosw]

Hey @ARCIST-AI, thanks for providing the additional context!

We're already looking into the new HTTP-based replacement for SSE here: #23.

However, I’m not entirely sure if this is directly related to the latest Cursor update. To help us investigate further, could you please share the following:

Your current Cursor version (we're running v0.47.8, which works with the current main branch of this repo)

The output logs from the MCP server after Cursor attempts to connect

Appreciate your help — happy to dig into this further with you!

[ARCIST-AI]

Hey @ARCIST-AI, thanks for providing the additional context!

We're already looking into the new HTTP-based replacement for SSE here: #23.

However, I’m not entirely sure if this is directly related to the latest Cursor update. To help us investigate further, could you please share the following:

Your current Cursor version (we're running v0.47.8, which works with the current main branch of this repo)

The output logs from the MCP server after Cursor attempts to connect

Appreciate your help — happy to dig into this further with you!

Hi @michiosw,

I'm experiencing the same issue with Cursor version 0.47.8. After seeing your analysis of the MCP transport protocol changes, I can provide additional context from my testing:

Environment & Setup

• macOS Sonoma 24.3.0 (Darwin)
• Latest Cursor with MCP support
• browser-use-mcp-server cloned from main branch

Error Analysis

1. Initial Connection:

   INFO: 127.0.0.1:55301 - "GET /sse HTTP/1.1" 200 OK
   INFO: 127.0.0.1:55494 - "GET /sse HTTP/1.1" 200 OK
   

   The SSE endpoint connects successfully.

2. Task Processing Attempt:

   INFO [mcp.server.lowlevel.server] Processing request of type ListToolsRequest
   INFO [agent] 🚀 Starting task: First, navigate to https://news.ycombinator.com...
   

   The server accepts and begins processing the task.

3. Critical Error:

   ERROR [server] Error in handle_sse: unhandled errors in a TaskGroup (1 sub-exception)
   RuntimeError: Received request before initialization was complete
   

   This appears to align with your analysis regarding the SSE transport method and initialization timing issues.

Correlation with PR #206

Your observation about the MCP protocol transport changes (PR #206) removing the /sse endpoint seems particularly relevant given the error pattern we're seeing. The current error suggests a race condition or initialization sequence issue that could be related to how the SSE transport is handling state.

I found the transports specification repo so I’ll see what i can do with it.

Let me know if you need any additional error logs or testing with specific configurations.