# fix\(server\): Antigravity starts for Linux users without a passwd entry · PR \#23386 · pingdotgg/t3code

[View on GitCafe](https://git.cafe/pingdotgg/t3code/pull/23386)

Repository: [pingdotgg/t3code](https://git.cafe/pingdotgg/t3code)

Visibility: public

State: open

Source repository: pingdotgg/t3code

Source branch: fix/issue-23005

Target branch: main

Head commit: 5f585059ab210188feb0010c864b11b030f25caf

[Discussion and reviews](https://git.cafe/pingdotgg/t3code/pull/23386)

[Commits](https://git.cafe/pingdotgg/t3code/pull/23386/commits?format=markdown)

[Files changed](https://git.cafe/pingdotgg/t3code/pull/23386/diffs?format=markdown)

## Description

---

## Problem

Antigravity's bundled runtime exits 255 before ACP initialization for Debian 13 OS Login users when NSS user lookup fails and `HOME` is under `/home`. Settings reports an installation failure and removes the downloaded runtime.

## Change

Pass the runtime's existing user-information fallback flag on Linux through the shared spawn builder. Installation validation and provider sessions can initialize using the existing process environment when passwd lookup fails.

## Scope and approval

Fixes #23002

Triaged bug via the automated issue flow; GitCafe mirror [#23005](https://git.cafe/pingdotgg/t3code/issues/23005).

## Verification

- Red assertion fails on main because the Linux launch lacks the fallback flag; retained in the existing spawn coverage.
- `vp test run apps/server/src/provider/antigravityAuthSupport.test.ts apps/server/src/provider/Drivers/AntigravityDriver.test.ts`: 30 tests passed after merging main.
- Targeted lint on all three changed files passed; `git diff --check` passed.
- Scoped server typecheck did not complete within 30 minutes on the overloaded VM; CI covers it.

The real pinned 1.3.0 runtime was launched using the actual shared spawn builder from each revision in an isolated Debian 13 x86-64 fixture with OS Login NSS libraries. No UI code changes; the visual evidence matrix is empty.

| Fixture | Before: [3b95e7831b](https://git.cafe/pingdotgg/t3code/commit/3b95e7831b11b17627dff16843bc087bfca397ec) | After: [5f585059ab](https://git.cafe/pingdotgg/t3code/commit/5f585059ab210188feb0010c864b11b030f25caf) |
| --- | --- | --- |
| UID 54321 absent from passwd; existing owned `HOME=/home/anything` | Exit 255, no ACP output | Exit 0, 899-byte initialize result |
| Same UID with a passwd entry | Exit 0, 899-byte initialize result | Exit 0, 899-byte initialize result |

[Before transcript](https://gh-file-drop-api-prod-mi5fy3sowv63ufte.pinglabs.workers.dev/f/d3adab64ccb06c8f/t3-before.log), [after transcript](https://gh-file-drop-api-prod-mi5fy3sowv63ufte.pinglabs.workers.dev/f/1008ec9af0eb3561/t3-after.log), [identity controls](https://gh-file-drop-api-prod-mi5fy3sowv63ufte.pinglabs.workers.dev/f/fe0a0482a0d8caa2/audit-controls.log), [red assertion](https://gh-file-drop-api-prod-mi5fy3sowv63ufte.pinglabs.workers.dev/f/a83add9691bd60b5/red-test.txt), [final tests](https://gh-file-drop-api-prod-mi5fy3sowv63ufte.pinglabs.workers.dev/f/376e06b6496c402e/merged-tests.log).

[Reproduction scripts, archive checksum, exact package versions, and evidence index](https://gh-file-drop-api-prod-mi5fy3sowv63ufte.pinglabs.workers.dev/f/740f5eba871c4166/evidence.md). No render behavior changed. The fixture uses synthetic identities and no credentials. A real GCE identity, Settings installation lifecycle, authenticated turns, and Linux ARM64 were not verified. macOS and Windows launch arguments are unchanged.

Implemented with Claude Opus 5.5 through the Claude Agent SDK harness; triage, runtime evidence, and review with GPT-6.1-Sol through the Codex harness and Claude Opus 5.5 through the Claude Agent SDK harness, orchestrated by T3 Code.