Custom executable path silently disables --session-name state restore (save works, restore doesn't)

[navidemad]

Summary

When a custom browser binary is set via AGENT_BROWSER_EXECUTABLE_PATH (or --executable-path), --session-name state persistence half-works: the state file is written correctly on close, but it is never restored on the next launch. The same commands with the default auto-managed engine restore fine.

Because the save path keeps working, the failure is silent and destructive: the next close overwrites the previously saved (good) state file with the empty context.

Environment

• agent-browser 0.27.2 (Homebrew, macos aarch64)
• macOS (Darwin 25.5.0), Apple Silicon
• Engines tested: Chrome for Testing 149.0.7827.115 (default, works), Google Chrome 149.0.7827.103 (fails), Brave 149.1.91.171 (fails)

Repro

Pass case, default engine:

agent-browser --session s1 --session-name t1 open https://example.com
agent-browser --session s1 --session-name t1 eval "localStorage.setItem('k','v'); document.cookie='c=v; max-age=86400'; 1"
agent-browser --session s1 --session-name t1 close
sleep 2
agent-browser --session s2 --session-name t1 open https://example.com
agent-browser --session s2 --session-name t1 eval "localStorage.getItem('k') + ' / ' + document.cookie"
# => "v / c=v"

Fail case, identical commands with a custom executable (fresh name, daemons killed first):

export AGENT_BROWSER_EXECUTABLE_PATH="/Applications/Google Chrome.app/Contents/MacOS/Google Chrome"
agent-browser --session s3 --session-name t2 open https://example.com
agent-browser --session s3 --session-name t2 eval "localStorage.setItem('k','v'); document.cookie='c=v; max-age=86400'; 1"
agent-browser --session s3 --session-name t2 close
sleep 2
agent-browser --session s4 --session-name t2 open https://example.com
agent-browser --session s4 --session-name t2 eval "localStorage.getItem('k') + ' / ' + document.cookie"
# => "null / "

What I checked

• The save side is fine in the fail case: after the first close, ~/.agent-browser/sessions/t2-s3.json contains 1 cookie and 1 origin (localStorage). Only the restore is skipped.
• Same result with the Brave binary, and with --executable-path instead of the env var.
• Same result whether the second run reuses the same --session or a fresh one.
• Removing the custom executable (falling back to the auto-managed Chrome for Testing) makes the exact same commands pass.

Possibly related to #1335, which is about the env-var form of --session-name not restoring; this one reproduces with the CLI flag itself, and the trigger is the custom executable path.