PR: https://git.cafe/pingdotgg/t3code/pulls/27084
Baseline: github/main 32ecd71726 (separate /home/user/main worktree)
Head: 80f509a27fd1a8d1f00b35c57f1816201f5a2360
Environment: Linux Boat VM, real vp run dev server, Playwright 1.60 + /usr/bin/google-chrome.

Browser-driven runtime observations:
1. Added project from a real git checkout through Add project > Local folder.
2. Selected Codex GPT-6.1-Sol and sent a real turn through the composer.
   PR client rendered: device update verification ready.
3. Temporarily moved every npm/pnpm executable present on the server PATH aside.
   No fake executables, response interception, or mocked process runner.
4. Baseline Settings > Devices > Device hub > Update:
   Device update device tool failed: The device command failed.
5. PR Settings > Devices > Device hub > Update:
   Device update device tool failed: Neither npm nor pnpm was found on this host. Install Node.js with npm on this host, make npm available to the T3 server, then retry.
6. PR Settings > Devices > Agent device > Update: same actionable error.
7. Check versions remained usable after the failed hub update.
8. Restored all npm/pnpm executables; retried both Update buttons in Settings.
   Hub Installed: 0.19.0-canary-20261023-1357114
   Agent Installed: 0.21.31
   Both matched Required; both Update buttons disappeared.
9. find /home/user/.t3 -name ".staging-*": no results.
   .install-complete files exist for both installed versions.

Remote Blacksmith command:
vp i && vp test run apps/server/src/device/DeviceToolchain.test.ts apps/server/src/device/DeviceService.test.ts
Result: 2 test files passed, 46 tests passed.
PR status: 30 successful checks, 0 pending, 0 failing.
No source changes, commits, or pushes were needed.

Not exercised: native iOS/Android, Electron shell, macOS/Windows, SSH host updates,
successful pnpm fallback, live permission-denied/nonzero-install failures.
The existing focused tests cover fallback and permission/nonzero error classification.