Headless Environment Detection Improvement / Claude Code v2.1.191

What changed: The check for whether to skip browser-open operations (e.g., after auth) now handles more cases correctly:

Respects BROWSER="" (browser explicitly set to empty string) vs BROWSER=true (legacy signal meaning "use default").
Treats SSH_CONNECTION presence as a headless signal.
On Linux, treats absence of both DISPLAY and WAYLAND_DISPLAY as headless.

This reduces spurious browser-open attempts in remote/SSH environments.

Evidence

Headless check function (search for "SSH_CONNECTION" alongside "WAYLAND_DISPLAY")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

The build it came inv2.1.191

24 Jun 2026 · 21 entries, this one is #15.

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Names in this entry

envBROWSER
The command Claude Code runs to open a URL in a browser, falling back to xdg-open on Linux; a value other than true also stops an SSH session or a Linux session with no display from being treated as headless, so MCP authorization and sign-in flows treat the session as able to open a browser. Claude Code sets it too: background sessions it launches get BROWSER=true (a no-op command) except in exec mode, and while a terminal is attached they take that terminal's value. It is also on Claude Code's lists of program-launching variables, which some hardened subprocess environments drop.
envSSH_CONNECTION
More environment variables go through the central registry that handles allowlisting and scrubbing.
envDISPLAY
On Linux, copy and paste now work even without wl-copy, xclip or xsel installed.
envWAYLAND_DISPLAY
On Wayland, clipboard and primary-selection writes now happen in order, not simultaneously.

Is this right?