browser subagent fails in wayland

[sigmaSd]

What happened?

browser subagnet fails

 Browser Agent Finished                                                                                  │     
│                                                                                                         │     
│ Termination Reason: GOAL                                                                                │     
│                                                                                                         │     
│ Result:                                                                                                 │     
│ {                                                                                                       │     
│   "success": false,                                                                                     │     
│   "summary": "Terminal Failure: Failed to open a new page. The browser implementation returned the      │     
│ following error: \"Missing X server to start the headful browser. Either set headless to true or use    │     
│ xvfb-run to run your Puppeteer script.\" This error appears unrecoverable as I do not have direct       │     
│ control over the browser's launch parameters (e.g., setting headless=true) through the available        │     
│ tools. According to the instructions, this is a terminal failure. Please check the browser              │     
│ configuration or try again."                                                                            │     
│ }                                                                                                       │     
│              

What did you expect to happen?

I expected it to not error, I'm using wayland , if the gui is not possible atleast it should fallback to headless

Client information

Client Information

Run gemini to enter the interactive CLI, then run the /about command.

> /about
 About Gemini CLI                                                                                            │ 
│                                                                                                             │ 
│ CLI Version                          0.33.0                                                                 │ 
│ Git Commit                           6ee19e1f6                                                              │ 
│ Model                                Auto (Gemini 3)                                                        │ 
│ Sandbox                              no sandbox                                                             │ 
│ OS                                   linux                                                                  │ 
│ Tier                                 Gemini Code Assist for individuals                                     │ 
│                                                                                                             │ 
╰─────────────────────

Login information

No response

Anything else we need to know?

No response

[sigmaSd]

I just noticed the headless option I guess that should work around this

[hsm207]

For the maintainers, I found the cause of this issue:

The root cause is due to two environment propagation issue:

1. Transport Environment Isolation: The StdioClientTransport within browserManager.ts does not explicitly pass the host's process.env to the chrome-devtools-mcp sub-process. This leads to the sub-process failing to inherit display environment variables (DISPLAY, WAYLAND_DISPLAY, XDG_RUNTIME_DIR).
2. Restrictive Sanitization Logic: The project's environmentSanitization.ts utility (used in other contexts) has a whitelist that excludes these display variables, meaning even if they were passed, they will be redacted by other parts of the system.

[sigmaSd]

headless: true doesnt' work as well, the agent still tries to find an xserver