# Final merged-head proof addendum

VERDICT: **SUFFICIENT** for the synthetic Linux desktop SDK-discovery claim.

For [#11648](https://git.cafe/pingdotgg/t3code/pulls/11648), mirrored [#11648](https://github.com/pingdotgg/t3code/pull/11648), verified only `/home/ubuntu/wt/pr-11648`, branch `takeover/pr-11648`, at [131173e0f4](https://github.com/pingdotgg/t3code/commit/131173e0f4165bbe4a383235b7568eb146b3e8b7). This is a local merge of reviewed [e90cc01e4b](https://github.com/pingdotgg/t3code/commit/e90cc01e4b95283528d5f65dedaa19a7114a3cd8) and main [3eb836664e](https://github.com/pingdotgg/t3code/commit/3eb836664eb1a5d0102055fe1e4a7fc5c1d8a9c7); it does not assert the PR has landed.

## Equivalence and historical attribution

Independently checked `git diff e90cc01e4b HEAD -- apps/desktop apps/web packages/shared/src/shell.ts`: empty. The device service directory is also unchanged. Recorded matching source hashes for DesktopShellEnvironment, DesktopBackendConfiguration, LocalDeviceHost and shared shell. Diff against pinned origin/main remains exactly two files, 47 additions; that complete patch is byte-for-byte identical to the prior base-to-reviewed patch. See source-equivalence.json, patch-equivalence.json and merge-changes.txt.

The historical 44/44 matrix remains evidence at [e90cc01e4b](https://github.com/pingdotgg/t3code/commit/e90cc01e4b95283528d5f65dedaa19a7114a3cd8), with before shell source from [843f4e3529](https://github.com/pingdotgg/t3code/commit/843f4e35292391897089535e8f1af59b322e70f8). It has **not** been rerun or relabeled as final-head captures. Its [PASS2 audit](https://gh-file-drop-api-prod-mi5fy3sowv63ufte.pinglabs.workers.dev/f/714ff2b957f27284/audit-report.md) remains applicable through source equivalence, supplemented by the fresh integration runs below. Earlier PASS1 labeling at [b6c944c9b8](https://github.com/pingdotgg/t3code/commit/b6c944c9b8e36e9a7faddfafaf291677a5663eb9) differed only in tests. Round-two Sol/Opus MERGE reviews are historical at the reviewed head, not new merged-head reviews.

The C11-after final process-tree file was overwritten after shutdown and is empty. That caveat remains unchanged; exec-time tuple, backend-child sentinels and media support the historical row. No universal surviving-final-tree claim is made.

## Fresh exact-head integration

Ran `vp run build:desktop` successfully (5/5 tasks, cache disabled), rebuilding web, backend and Electron from the merged checkout. This is a fresh server build, not relabeled old output. Build log and main/backend SHA-256 hashes are included; the copied Electron sourcemap contains the exact final DesktopShellEnvironment source. Real Electron 44.9.3 launched against the rebuilt backend.

Each run used `env -i`, its own throwaway HOME/T3 home, `T3CODE_DEV_SEED=0`, and a dedicated owned headless desktop. No live data or seeding. Synthetic h/r/j roots were outside default SDK locations and launch PATH. The bash profile exported distinct h/r roots in both runs.

| Fresh row | Inherited tuple | Backend exec tuple | Selected fixture | Result |
|---|---|---|---|---|
| A1-after | absent / absent | h / r | h | PASS |
| C3-after | absent / j | absent / j | j | PASS |

Captured backend PIDs 2351928 and 2352715 were direct children of owned Electron PIDs 2351627 and 2352412. Shell observer confirms `/bin/bash -ilc` and isolated HOME. Discovery emulator sentinels directly parent to the respective backend and select h/j. C3 backend ANDROID_HOME remains absent; downstream DeviceHost normalization to j is not confused with exec-time hydration. Both UI paths completed onboarding → Settings → Integrations → Device hub → Refresh and report SDK installed/no virtual device.

Fresh A1 at final head:

![Final-head A1: profile SDK discovered, no AVD](https://gh-file-drop-api-prod-mi5fy3sowv63ufte.pinglabs.workers.dev/f/ec753cb262c9002f/still-1.png)

[Fresh A1 recording](https://gh-file-drop-api-prod-mi5fy3sowv63ufte.pinglabs.workers.dev/f/a7ff44b55c2450a9/interaction.mp4). [Fresh C3 still](https://gh-file-drop-api-prod-mi5fy3sowv63ufte.pinglabs.workers.dev/f/dca42280188ce086/still-1.png) and [recording](https://gh-file-drop-api-prod-mi5fy3sowv63ufte.pinglabs.workers.dev/f/f49069687de5ae63/interaction.mp4). Both paired stills are pixel-identical over 500 ms. Both 7.8-second, 39-frame recordings fully decode; sampled frame sheets and both final stills were visually inspected. Status-only stills can match despite different selected roots; backend tuples and command sentinels establish selection.

Focused final-head tests: **14/14 passed**, `vp test run apps/desktop/src/shell/DesktopShellEnvironment.test.ts`. No repo-wide checks. Build warnings concern chunk size and CJS import.meta; Electron logs contain termination-time GPU/network errors after successful captures, not a discovery failure.

Cleanup uses captured owned processes only; cleanup.json reports zero remaining recorded live PIDs. Fresh nonempty process trees are preserved before stop and never overwritten with an empty observation. Worktree stayed clean at the exact requested SHA. No tracked edits, commit, push, PR write, or watch. Only local draft and /tmp evidence changed; PR registration is thread metadata.

Scope: synthetic Linux discovery, no AVD/emulator boot; no Windows/macOS runtime certification, remote provisioning or unrelated backend feature certification. W1/W2 and S1–S6 retain historical source-control status. Web/desktop source paths are unchanged; mobile/provider entry points are unaffected by this patch. Main's unrelated backend changes are covered here only by these fresh desktop integration runs.

FRICTION category | issue | prevention
--- | --- | ---
runbook | historical last-row tree can be overwritten after stop | preserve nonempty pre-stop snapshot; skip empty overwrite
build | source-equivalent desktop does not establish merged backend provenance | rebuild full desktop dependency graph and hash actual main/backend artifacts
reporting | historical matrix can be mistaken for final-SHA captures | retain original SHAs and distinguish the two fresh final-head rows

Verified by GPT-6.1 Sol through Codex in T3 Code; ghdrop used for publication.