PR #23759, docs-only; tested 2026-10-30 on disposable Linux Boat VM.
main: fa4e4677c0, separate /home/user/main worktree; vp i passed.
PR: 1e03b48a95a6215200f2e11f07459bd278e4d318; vp i passed.
No mocked CLI, fixture database, or replay provider used. T3CODE_DEV_SEED=0.

Both starts used background vp run dev with T3CODE_TAILSCALE_SERVE=true.
main dev-runner: serverPort=16733 webPort=8693 baseDir=/home/user/main/.t3
main: Listening on http://127.0.0.1:16733
main: WARN Failed to configure Tailscale Serve
      TailscaleCommandSpawnError; executable=tailscale; subcommand=serve
PR dev-runner: serverPort=13773 webPort=5733 baseDir=/home/user/t3code/.t3
PR: Listening on http://127.0.0.1:13773
PR: WARN Failed to configure Tailscale Serve
    TailscaleCommandSpawnError; executable=tailscale; subcommand=serve

node apps/server/src/bin.ts pair --base-dir <isolated-home> --tailscale
Both: TailscaleUnavailableError: Could not talk to Tailscale. Is tailscaled running? Try `tailscale status`.
Underlying failure: spawn tailscale ENOENT. This VM has no Tailscale executable or authenticated tailnet.
This proves missing-install failure handling, not the three tailnet prerequisite cases.

Browser: Playwright 1.60.0 from repo dependencies; /usr/bin/google-chrome.
Both: consumed startup local pairing link in browser; authenticated session and WebSocket connected.
Both: added repository project through Add project > Local folder; created thread through composer.
Both: selected Codex GPT-6.1-Sol; submitted read-only documentation inspection.
main: real completed provider turn reported MagicDNS, HTTPS certificates and Linux operator permissions absent.
PR: real completed provider turn (14s) reported all three present and quoted exact paragraph with both clickable links.
PR: unauthenticated GET /api/orchestration/shell returned 401 (expected).

Both added Tailscale documentation URLs: HTTP 200.
HTTPS source: enable MagicDNS, then HTTPS Certificates > Enable HTTPS.
Linux source: root normally manages daemon; allow another user with sudo tailscale set --operator=<USERNAME>.

Blacksmith: vp i passed; vp run check:changed passed format on one docs file; knip skipped (no code/manifest changes).
Remote check initially lacked merge base; fetched exact fork branch history and set remote base ref to 4eae8ae011e2e56ca20159c13f3fb8a2ac49a991, then check passed.
No source changes, commits or pushes made.

NOT VERIFIED: successful tailnet HTTPS; individual MagicDNS/certificate/operator failures and recovery; cross-device access; native desktop/mobile; macOS/Windows.
Reason: no installed/authenticated Tailscale tailnet on this VM; no native clients exercised.