Serena MCP keeps popping up broken browser window when App goes into foreground

Open 💬 5 comments Opened Feb 6, 2026 by amit777

What version of the Codex App are you using (From “About Codex” dialog)?

Version 260205.1301 (554)

What subscription do you have?

pro

What issue are you seeing?

I downloaded the App for the first time. I have the following MCP config launching (i got this from the codex cli which I presume the App is also using)

/mcp

🔌  MCP Tools

  • serena
    • Status: enabled
    • Auth: Unsupported
    • Command: uvx --from git+https://github.com/oraios/serena serena start-mcp-server --context codex
    • Tools: activate_project, check_onboarding_performed, delete_memory, edit_memory, find_file, find_referencing_symbols, find_symbol, get_current_config,
get_symbols_overview, initial_instructions, insert_after_symbol, insert_before_symbol, list_dir, list_memories, onboarding, read_memory, rename_symbol,
replace_symbol_body, search_for_pattern, think_about_collected_information, think_about_task_adherence, think_about_whether_you_are_done, write_memory
    • Resources: (none)
    • Resource templates: (none)

Every time I try to click on the app, it seems like it's trying to launch the serena MCP, but failing. And it goes to a browser window URL like this: http://127.0.0.1:24289/dashboard/index.html. (this is a serena dashboard URL, but it's not running. ERR_CONNECTION_REFUSED)

What steps can reproduce the bug?

Configure the serena MCP for use in codex-cli.
Make sure it works.
Download App and Launch

What is the expected behavior?

It should not keep launching the failed URL.

Additional information

_No response_

View original on GitHub ↗

5 Comments

adronitis · 6 months ago

Having the same issue at the moment, but the Serena URL that opens is working for me. But everytime I am in the focus date of Codex, it opens up the Serena again. Version 26.217.1959 (669)

sstklen · 6 months ago

This looks like the Codex desktop App is re-initializing the Serena MCP server process each time the application window regains foreground focus — which causes Serena to re-launch its dashboard browser window on every focus event. The second commenter confirms the same pattern (working URL, but opens repeatedly), which supports this theory.

Possible workaround — suppress the browser launch:

Since the root issue is Serena opening a browser window on startup, you can try setting BROWSER=echo in the MCP server's environment config. This is a standard POSIX convention that prevents child processes from opening a real browser:

{
  "serena": {
    "command": "uvx",
    "args": [
      "--from", "git+https://github.com/oraios/serena",
      "serena", "start-mcp-server",
      "--context", "codex"
    ],
    "env": {
      "BROWSER": "echo"
    }
  }
}

Note: This works if Serena uses the $BROWSER environment variable or standard open/xdg-open calls internally. If Serena launches the browser through a different mechanism, this may not help — in that case, it would be worth opening a separate issue on Serena's repo requesting a --no-browser or headless mode flag.

The underlying behavior (MCP servers being restarted on every focus event rather than maintaining persistent connections) seems like a Codex App bug worth tracking separately.

_Disclosure: This analysis is from Confucius Debug, an AI-powered community KB for agent bugs. Please verify before applying._

---
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ZuluLame · 5 months ago

Same here, I have the dashboard page open: http://127.0.0.1:24282/dashboard/index.html, but still a new tab for http://127.0.0.1:24285/dashboard/index.html gets being open again and again, quite annoying as the focus switches from VS Code to the browser each time

anodynos · 5 months ago

[EDIT]: The issue was in JetBrains WebStorm, not CC.

I have the same issue, but I'm not using Codex; I'm using Claude Code, on Windows with WSL2 backed Docker

http://127.0.0.1:24282/dashboard/index.html pops every now and then.

Acture · 5 months ago

Same here. Keeps poping with Claude Code. Wasn't like this 1-2 days ago.