[MarioCadenas]

TSX drafts now run in the design plugin next to the HTML drafts, on branch work/38-serve-tsx-drafts-from-the-desi (one commit, 9ff9dc62a, nothing merged). I ran it live through the AI Gateway in an app scaffolded from template/, and it works end to end.

Results of the live runs:

• Taxi dashboard: 41s, all 3 drafts compiled, one needed a fix round.
• Tetris: 23s, all 3 compiled, and it replaced the taxi drafts.
• In Chrome, all 3 pages reached ready in light and dark mode, and /design/__status showed tsx moving through writing → type-checking → rendering → ready.
• Lock-in left a working /design (ready: true) and the app's own tsc still passes.
• Repo checks pass: 959 tests, pnpm -r typecheck, pnpm check and knip are clean.

What I added:

• appkit design tsx-drafts --prompt … --answers … --name <prefix>: KIT-37's writer, reused with its prompt files (components.schema.json, the appkit-ui export list, the example page and mock), with up to 2 fix rounds after the type check.
  • Files are written in client/src/design/.staging/, and a page moves into pages/ only once it compiles.
  • A new run deletes only the previous run's drafts, not other design pages.
  • --print-prompt prints the cached system prompt.
• appkit design lock-in <name> [--home]: keeps the chosen page as /design/index.tsx, or with --home as client/src/pages/home/HomePage.tsx. It deletes the other drafts; the only change to the code is the ../mock import becoming ./mock.
• A tsx section in /design/__status: each draft shows writing, type-checking, rendering, ready or failed. ready and failed come from what the page reports from the browser.
• TSX drafts are ordinary /design/<name> pages, so the plugin's existing per-page error boundary and appkit:design-ready message already cover them. The HTML draft path is untouched.
• A "TSX drafts" section in docs/docs/plugins/design.md.

Bug fixed during the live run: Tailwind didn't style a newly added page until the stylesheet changed. The writer now touches client/src/index.css, as KIT-37 did.

How to consume it: tarballs databricks-appkit-0.90.0.tgz and databricks-appkit-ui-0.90.0.tgz are in ~/.herdr-projects/reports/app-kit/38/. Install both as file: dependencies; both are needed because the appkit command comes from the appkit-ui package. The closing note has the exact commands, the checksums and how to rebuild them.

Caveats:

• KIT-37 (PR chore(playground): prototype TSX drafts in an AppKit playground #706) isn't merged, so I copied its code rather than building on its branch.
• --home doesn't edit App.tsx; the agent still has to route the page at /.
• I haven't run it inside the real App Builder, and the tarballs are local builds, not published to npm.
• I ran pnpm store prune once on the global pnpm store while reinstalling the test app.

Also noticed:

• packages/appkit/src/plugins/design/vite-plugin.ts: hand-written pages added while the dev server runs have the same Tailwind styling gap.
• A lint-staged automatic backup (2b8879a) entry is sitting in the shared git stash; it isn't from this task.

Task: KIT-38 (app-kit/38)

[MarioCadenas]

Review 1 · Pass · 2 minor

Does the change do what the task asked? Yes. Gate: major and worse must be fixed.

The TSX draft path is built as asked: a writer CLI that reuses KIT-37's prompt files and runs tsc with up to 2 fix rounds, staging so a page only shows once it compiles, a tsx section in /design/__status, and lock-in. The HTML path is not touched, and the branch is pushed. I did not repeat the live AI Gateway run, so the end-to-end claims rest on the author's report plus the unit tests I ran.

Not required (below the gate)

• minor: lock-in --home overwrites client/src/pages/home/HomePage.tsx without asking and does not route it at /, so the user still has to edit App.tsx by hand (the command description says so). (packages/shared/src/cli/commands/design/tsx-drafts.ts lockInTsxDraft)
  Proof: Read the code: fs.writeFile(target) is unconditional and App.tsx is never touched.
• minor: A new tsx-drafts run replaces the shared client/src/design/mock.ts, so a non-run design page or a locked-in index.tsx that imports ./mock or ../mock can silently get different data or break. (packages/shared/src/cli/commands/design/tsx-drafts.ts writeTsxDrafts)
  Proof: Read the code: the mock is copied over designDir/mock.ts with no check for other importers.

[MarioCadenas]

Review 2 · Fail · 1 major, 1 minor

Does the change do what the task asked? Yes. Gate: major and worse must be fixed.

The branch adds per-page compiled/compileError/state to /design/__status on top of KIT-1's TSX page serving, leaves HTML drafts alone, and documents what a builder writes. The design tests pass. The one real gap: the docs leave out the Tailwind step the agent says it needed in its own live run.

Required

• major: The agent says new pages stay unstyled until client/src/index.css is touched, but the docs' builder contract doesn't mention this, so a builder following the docs gets unstyled drafts. (docs/docs/plugins/design.md (TSX drafts section))
  Proof: Read the docs diff: no mention of index.css or Tailwind rescanning. The agent's own report says it hit this in the live run.

Not required (below the gate)

• minor: Every /design/__status poll compiles every page's module graph server-side, which could slow down frequent builder polling when there are many drafts. (packages/appkit/src/plugins/design/vite-plugin.ts:926)
  Proof: Code read only. Not measured.

[github-actions]

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📦 Try this PR's app template

Scaffolds a new app from this PR's SDK build. Run it in any folder (requires the GitHub CLI — gh auth login — and the Databricks CLI):

gh run download 41927351703 -R databricks/appkit -n appkit-template-0.90.0-pr.cd41c28-work-38-serve-tsx-drafts-from-the-desi-707 -D appkit-pr-707 \
  && unzip -o "appkit-pr-707/appkit-template-0.90.0-pr.cd41c28-work-38-serve-tsx-drafts-from-the-desi-707.zip" -d "appkit-pr-707" \
  && databricks apps init --template "appkit-pr-707"

The template pins @databricks/appkit and @databricks/appkit-ui to tarballs built from this branch, so the scaffolded app runs against this PR's code.

[MarioCadenas]

Review 3 · Pass · 1 minor

Does the change do what the task asked? Yes. Gate: major and worse must be fixed.

F3 is fixed: the TSX drafts section of the design plugin docs now tells the builder to touch client/src/index.css after moving a page in, and explains why. F4 was deliberately left as is: every status poll still compiles each page's module graph, and nobody has measured what that costs.

Not required (below the gate)

• minor: Every /design/__status poll still compiles every page's module graph server-side; the agent assumes Vite's cache keeps it cheap but did not measure it. (packages/appkit/src/plugins/design/vite-plugin.ts:926)
  Proof: Commit b987252 touches only docs/docs/plugins/design.md; vite-plugin.ts is unchanged.