Introduce the Electron desktop shell alongside the existing React renderer and local Bun server boundary. The migration keeps the DesktopHost contract explicit across Tauri, Electron, and browser runtimes while adding Electron main/preload services for dialogs, shell, notifications, updates, tray/window lifecycle, terminal, preview WebContentsView, app mode, and release/package validation.
The commit also carries the latest local main desktop command updates, including agent slash entries and hidden-by-default markdown thinking details, so the packaged Electron build matches the current main UX surface.
Constraint: React renderer, local Bun server, REST/WebSocket, and sidecar boundaries must remain reusable during the migration
Constraint: macOS dev packages are ad-hoc signed and cannot prove Developer ID notarization or Gatekeeper release launch
Rejected: Browser-only smoke validation | it cannot exercise native dialogs, keychain prompts, notification behavior, or packaged app startup
Confidence: medium
Scope-risk: broad
Directive: Do not remove Tauri host support until signed Electron release artifacts pass native OS smoke on macOS, Windows, and Linux
Tested: bun run check:desktop
Tested: cd desktop && bun run check:electron
Tested: CSC_IDENTITY_AUTO_DISCOVERY=false bun run electron📦dir
Tested: bun run test:package-smoke --platform macos --package-kind dir --artifacts-dir desktop/build-artifacts/electron
Tested: Computer Use read packaged Electron app window at desktop/build-artifacts/electron/mac-arm64/Claude Code Haha.app
Not-tested: Developer ID signed/notarized Gatekeeper launch
Not-tested: Real OS notification click-to-session action
Not-tested: Windows and Linux packaged app smoke on real hosts
Preview annotations should keep the selected element readable. The selected rectangle now carries a stronger translucent blue fill, while the numbered badge is a separate high-contrast fixed overlay placed outside the selected rect and clamped to the viewport.
Constraint: No issue number was provided for this task.
Constraint: Preserve the DOM-captured annotation path introduced for viewport-safe screenshots.
Rejected: Put the badge inside the selected box | it obscures compact buttons and labels.
Rejected: Return to canvas-side badge drawing | that reintroduces the separate coordinate system.
Confidence: high
Scope-risk: narrow
Directive: Keep numbered badges outside compact selected targets unless visual evidence shows a better non-obscuring placement.
Tested: cd desktop && bun run test --run src/preview-agent/screenshot.test.ts src/preview-agent/picker.test.ts src/preview-agent/metadata.test.ts src/preview-agent/protocol.test.ts src/preview-agent/bridge.test.ts src/preview-agent/editBubble.test.ts
Tested: cd desktop && bun run lint
Tested: cd desktop && bun run build:preview-agent
Tested: bun run check:desktop
Tested: git diff --check
Not-tested: Real Tauri webview visual smoke.
Selection screenshots were drawing the marker after html2canvas finished by
mapping DOM coordinates onto a separate canvas. That leaves room for drift when
html2canvas renders at a different output size, the viewport is resized, or the
thumbnail is compressed. The marker is now a fixed DOM overlay captured with the
page itself, so the chosen element and its marker share the same viewport,
layout, crop, and scale path.
Constraint: No issue number was provided for this task.
Constraint: Preserve the existing selection event payload and preview bridge protocol.
Rejected: Keep canvas post-processing with more scale math | it still maintains a second coordinate system beside the rendered page.
Rejected: Keep the unused annotate module | it would preserve the stale path that caused this class of drift.
Confidence: high
Scope-risk: narrow
Directive: Do not reintroduce canvas-side selection marker math unless it is proven against resized and scaled viewport captures.
Tested: cd desktop && bun run test --run src/preview-agent/screenshot.test.ts src/preview-agent/picker.test.ts src/preview-agent/metadata.test.ts src/preview-agent/protocol.test.ts src/preview-agent/bridge.test.ts src/preview-agent/editBubble.test.ts
Tested: cd desktop && bun run lint
Tested: cd desktop && bun run build:preview-agent
Tested: bun run check:desktop
Tested: git diff --check
Not-tested: Real Tauri webview visual smoke.
Element selection from the local preview should preserve the visual target
the user picked and send the confirmed request directly to chat. The
screenshot now captures the visible viewport before drawing the marker, and
the selection event sends a model-facing prompt while the chat UI shows only
the annotated image and compact element label.
Constraint: No issue number was provided for this task.
Constraint: Keep the preview-agent protocol shape unchanged.
Rejected: Prefill the composer with the selection note | it keeps the old extra confirmation step and exposes implementation text in the input.
Rejected: Full-document annotation coordinates | body-relative captures drift from the viewport selection users see.
Confidence: high
Scope-risk: moderate
Directive: Do not route confirmed preview selections back through composer prefill without rechecking the Codex-style direct-send flow.
Tested: cd desktop && bun run test --run src/preview-agent/screenshot.test.ts src/lib/previewEvents.test.ts src/lib/selectionComposer.test.ts src/components/chat/AttachmentGallery.test.tsx src/stores/chatStore.test.ts
Tested: cd desktop && bun run lint
Tested: cd desktop && bun run build:preview-agent
Tested: bun run check:desktop
Tested: git diff --check
Not-tested: Real Tauri webview click-through smoke; in-app Browser automation timed out while local Vite HTTP smoke returned 200.
Wire createPicker into the preview-agent IIFE: enter/exit picker via host messages, bind DOM mousemove/click (capture phase) to picker hover/select, and on click emit a selection event carrying ElementMetadata + annotated screenshot. Route the selection event in previewEvents.ts through buildSelectionComposerText into queueComposerPrefill with the screenshot attachment.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
