terminal_tool() resolves a per-task cwd override that WINS over config["cwd"]:
cwd = overrides.get("cwd") or config["cwd"]
config["cwd"] is sanitized for container backends in _get_env_config() (host
prefixes /Users//home//C:\\/C:/ and relative paths are replaced with the
backend default /root). But the override was applied RAW — it was never run
through that guard. The gateway/TUI registers the host launch dir as a cwd
override for workspace tracking (tui_gateway/server.py _register_session_cwd
-> _terminal_task_cwd -> _session_cwd -> os.getcwd()), so on a container
backend a host path leaked straight to `docker run -w <host-path>`:
- Windows desktop: -w C:\Users\<user> -> container fails to start (exit 125)
- POSIX: -w /home/<user> -> same
The ACP adapter translates its override cwd (acp_adapter/session.py
_translate_acp_cwd), but the gateway path did neither translation nor
sanitization, so the override bypassed the one guard that would have caught it.
Fix: extract the host/relative-path predicate into a shared
_is_unusable_container_cwd() helper (so the existing _get_env_config()
sanitizer and the new guard can't drift), and re-apply it to the *resolved*
cwd at the override-resolution site. Valid in-container override paths
(RL/benchmark sandboxes that set cwd to /workspace, /root, ...) are absolute
non-host paths and pass through untouched.
Tests: unit-pin the predicate (Windows backslash/forwardslash, POSIX home,
macOS /Users, relative, valid container paths) AND an E2E call-site pin that
drives terminal_tool() with a host-path override registered and asserts the
cwd reaching _create_environment is sanitized. Mutation-verified: reverting
the call-site guard makes the two host-path E2E tests fail (showing the raw
host path leaking) while the valid-/workspace-override test stays green.
