[gwdp]

Why

A Stop request that arrives while a web-preview session is still starting does not end startup. The worker goes on through Simulator preparation, the host start and the preview tunnel, and then reports the session as ready. This applies to web-preview-only sessions and to legacy serve-sim sessions.

How

• Use the shared startup Stop watch from [build-tools] Stop agent-device startup when the session is stopped #4666, with a createStartupTasks startup signal, the same as Argent and Appium.
• Pass the startup signal to Simulator preparation, the host start and the ready report. On Stop, the pending work is cancelled, and the step ends without a ready report.
• End the watch after the ready report and before the lifetime wait.
• Finish the session host on every exit. Teardown errors stay visible.

Test Plan

• New controller tests: Stop while the host starts on macOS and Linux, a teardown failure after Stop during preview setup that stays visible, and a check that the watch ends before the lifetime wait.
• Claude Code ran the build-tools typecheck and the src/steps tests (1954 passed, 8 skipped), and the root build, typecheck, oxlint, oxfmt and Lerna tests (2511 passed, 8 skipped) on this commit.
• CI passes on 33a8525. Codecov reports all changed lines covered.
• Planned: a hosted check that Stop during web-preview startup ends the session without a ready report.

Authorship and LLM use

Gabe asked for Stop coverage for every Simulator session type, with one PR per type. Codex wrote the first version, and Devin found no issues in it. Claude Code rebased it onto the current stack. On Gabe's request, Claude Code changed it to use the shared startup watch from #4666, with the same startup code as Argent and Appium. Gabe reviewed the final diffs and can answer questions.

Generated with T3 Code, using Claude Code.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 75.39%. Comparing base (6fc41b4) to head (33a8525).

Additional details and impacted files

@@                          Coverage Diff                          @@
##           gwdp/appium-startup-stop-20261016    #4669      +/-   ##
=====================================================================
+ Coverage                              75.38%   75.39%   +0.01%     
=====================================================================
  Files                                   1056     1056              
  Lines                                  52371    52384      +13     
  Branches                               11381    11424      +43     
=====================================================================
+ Hits                                   39477    39491      +14     
+ Misses                                 11905    11904       -1     
  Partials                                 989      989              

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[github-actions]

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