When the web server is launched from inside a tmux pane it inherits TMUX/
TMUX_PANE. tmux's nesting guard then makes every new attach-bridge PTY
(`tmux attach-session`, used by codex/opencode/gemini and mux-wrapped claude)
exit code 1; the respawn controller recreates the dead bridge → infinite loop.
The existing guard in buildMuxAttachEnv() used `TMUX: undefined` on a
{...process.env} spread, which leaves the KEY present with value undefined —
node-pty serializes it as the literal string "TMUX=undefined", still tripping
the guard. (The working create path in tmux-manager.ts uses `delete`.)
Fix:
- Primary: delete process.env.TMUX / TMUX_PANE at web bootstrap (src/index.ts)
so every downstream {...process.env} spread is clean regardless of launch
context. `delete`, not `= undefined`.
- buildMuxAttachEnv(): build a copy and `delete` TMUX/TMUX_PANE/CLAUDECODE
(and COLORTERM when not truecolor) instead of `: undefined` — same node-pty
quirk affected all of them.
- Test: assert the keys are genuinely ABSENT (`'TMUX' in env === false`), not
merely undefined — the prior test only checked `toBeUndefined()`, which is
why the bug slipped through. Red→green confirmed.
Verified on isolated beta launched from inside tmux (inherited the poisonous
TMUX=codeman,980,7): created a codex session + triggered interactive attach —
the bridge `tmux -L codeman-beta attach-session` spawned with NO TMUX in its
env, attached successfully, zero "exited with code: 1", server healthy.
Circuit-breaker for repeated non-zero bridge exits (AC bullet 4, optional)
split to a follow-up. Deploy-pending (substrate): never auto-deployed.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Codeman maintainer