PR: https://git.cafe/pingdotgg/t3code/pulls/23434
GitHub: https://github.com/pingdotgg/t3code/pull/23434
PR HEAD: 22e38eeeaa67e503ae67378ef7902906b4c71d33
Baseline github/main: 305a90dce4
Environment: disposable Linux Boat VM. Playwright from repo dependencies driving /usr/bin/google-chrome.
Data: real project created in app, real Codex gpt-6.1-sol turns, real example.com browser tabs/cookies/localStorage. No mocks or fixtures.

RACE REPRODUCTION
Opened persistent default profile through running server preview.open RPC (main) / Codex preview_open tool (PR).
Paused only task-owned persistent Chromium parent briefly with SIGSTOP so the actual close remained pending.
In authenticated web page, sent two actual WebSocket RPC requests concurrently:
{_tag:"Request",id:<unique>,tag:"preview.clearProfile",payload:{profileId:"default"},headers:[]}
Observed real RPC replies and filesystem state, then resumed Chromium with SIGCONT in shell EXIT trap.

MAIN (server 16733, web 8693, isolated /home/user/main/.t3)
After 1.2 seconds while Chromium PID 34815 was stopped:
[{"caller":2,"result":{"_tag":"Success","value":null},"ms":29}]
STORAGE_DELETED
State: T (stopped)
BUG: second clear succeeded and deleted profile storage before Chromium finished closing.

PR (server 13774, web 5734, isolated /home/user/t3code/.t3)
After 1.2 seconds while Chromium PID 53826 was stopped:
[]
STORAGE_PRESENT
State: T (stopped)
After SIGCONT:
[{"caller":1,"result":{"_tag":"Success","value":null},"ms":1312},{"caller":2,"result":{"_tag":"Success","value":null},"ms":1312}]
STORAGE_DELETED
Default tab disappeared; incognito tab remained usable.
The deliberate pause exposes ordering; these times are not a performance comparison.

REAL PROVIDER / CLIENT READBACK
Codex gpt-6.1-sol used preview_open and preview_evaluate, prompted from the dev web UI:
Before clearing default: localStorage.verification = "clear-me", cookie = "verification=clear-me".
Incognito: localStorage.verification = "keep-me", cookie = "verification=keep-me".
After concurrent default clear, reopened default: localStorage.verification = null, document.cookie = "".
Incognito still: localStorage.verification = "keep-me", cookie = "verification=keep-me".
Then set default values to persist-me, closed/reopened tab normally:
localStorage.verification = "persist-me", cookie = "verification=persist-me".

CHECKS
Blacksmith: vp test run apps/server/src/preview/ServerBrowserContexts.test.ts: 10/10 passed.
Blacksmith: vp run check:changed: format, lint, knip, GraphQL, affected typechecks, focused tests all passed.
Worker needed explicit fetch of PR base/head history before check:changed could find merge-base.
Stored GitCafe CI: 29 successful, 0 failing, 0 pending at inspected exact head.

LIMITS
Desktop profile settings controls, native mobile, macOS/Windows, relay/tunnel connections not exercised.
Web profile controls are disabled on this head; clearing was exercised through authenticated WebSocket RPC used by clients.
No source changes or pushes required. No merge, close, rebase, force push, or label change.
Final incognito no-op: preview.clearProfile({profileId:"incognito"}) returned success. Real Codex readback still found keep-me in incognito and persist-me in default. Both tabs remained usable.