On New App Builder: Builder thread strands uncommitted edits — can't publish

💬 App Building
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Title: Builder thread strands uncommitted edits — can't publish

Severity: High — looks like lost work, no UI recovery, and the only workaround burns AI credits.

Environment: Retool React apps (Beta), driven via the MCP server (retool_create_or_append_react_app_thread_message), environmentName: production. Likely reproducible from in-editor Chat too.

Repro (minimal):

  1. Start a builder thread that edits several files.
  2. The agent runs an execute_backend_code test-run; the sandbox runtime drops mid-run, before the thread commits.
  3. Result: edits live in the working tree (they render in Preview, show in the Code tab, and retool_read_react_app_files returns them with the generationId) — but there's no commit on the branch.

Diagnostic signature (exact signals):

  • retool_get_react_app_thread_activity_status → state: "ACTIVE" and liveConnectionAvailable: false (active but no runtime).
  • retool_cancel_react_app_thread_activity / retool_respond_to_react_app_thread_review → generation_not_found.
  • Browser Publish: grayed out, "There are no new changes to publish."
  • retool_publish_react_app → "No commits found on this thread branch. Save or generate changes before publishing."
  • Code tab is read-only, so I can't hand-edit a file to force a dirty state either.

Expected: Working-tree changes should be recoverable/publishable — auto-commit when work lands, or a "Keep/commit changes" action — and Publish should reflect the working copy, not say "no changes" when it clearly differs from main.

Actual: Work is visible but unpublishable, with no recovery path in the UI.

Workaround (only thing that worked): send the same thread (reuse the generationId) another message telling it to make a real file write and commit. That produced a commit, which un-grayed Publish and let retool_publish_react_app succeed.

Likely root cause / where to look: the thread seems to commit only on successful turn completion; a runtime drop mid-execute_backend_code skips that commit, leaving the sandbox working tree ahead of the branch with no commit and no UI affordance to reconcile. Fixes: (1) harden execute_backend_code so a test-run can't strand the runtime; (2) make landed edits durable — auto-commit or expose a commit/keep action — and fix the "no changes to publish" state to reflect the actual working copy.