## Problem
Two audits of the repository (a workflow of finder, dedup and per-file verifier agents, run on 2026-10-11 against 1f4141e and again against 07f3e3c after a first round of refactoring) found dead code and features that were more machinery than the app needs: an Electron configuration-preset system with its own settings window, three copies of the about page, a hand-written `.env` parser, an "extended" system prompt nobody selected, two data migrations for formats from 2025-12 and 2026-01, a server-side example cache, type-to-confirm provider deletion, 81 unused dictionary keys, wrapper components around single call sites, and a long tail of unused exports, props, options and tests.
## Change
Every item below was either approved one by one or covered by "fix all of the others".
- **Electron:** the configuration-preset system is gone (settings window, preload, IPC, menu entry, dev watcher); `config-manager.ts` keeps only `userLocale`; `.env` files are parsed with `dotenv`. Entitlements file and a duplicate CI workflow removed; `test.yml` gets a type check and concurrency.
- **Server:** no extended prompt, no example cache, no `ENABLE_HISTORY_XML_REPLACE`, no message metadata or `hasConfig`; the connection test is one shared helper; EdgeOne loses its mock branch and model aliases; `DEBUG_LLM_PAYLOAD` logs message structure instead of payloads; Langfuse scoring helper; `apiKeyEnv` arrays kept and documented in `env.example` and the provider docs.
- **Pages:** one about page per language from a single component (old `/cn` and `/ja` URLs redirect with 308); layout uses `hasLocale`; the GitHub icon is a local component instead of `react-icons`; Cloudflare deploys without an R2 cache by default.
- **Chat and canvas:** the legacy `diagramHistory` conversion, the localStorage chat migration and the templates storage are gone; `chat-engine` reads the diagram through the context's refs; the diagram context has one tagged export path (`requestTaggedExport` / `fetchDiagramXml`); the screenshot check uses fetch + JSON and `generateText` with `Output.object`; `load-diagram` accepts `<svg:svg>` and strips the XML prolog.
- **Settings UI:** `model-selector` inlines its Dialog, Command and Tooltip; `ai-elements/model-selector`, `button-with-tooltip`, `error-toast` removed; no type-to-confirm, no footer, no `bedrockApiKey`; `use-model-config` loses the old-format migration; one reasoning component; the shimmer is CSS (no `motion`, no `@radix-ui/react-use-controllable-state`); 81 dictionary keys removed in all four languages.
- **MCP server:** `registerTool` / `ok` / `fail` replace per-tool try/catch; `syncFromBrowser`, `commitDocument`, `describePages`; the hand-written XML syntax check, unused result fields, `pickPageSelector`, `expandStyles` and the `host` attribute handling are gone; tests get a shared `setup.ts` and drive the server through the SDK client.
- **Prompt:** the web app's style rules come from the MCP drawing guide (`styleRules`), byte-identical to before.
- **Tests:** shared e2e helpers (`openApp`, `sse`, `toolCallEvents`, `chunkedReplies`); placeholder specs dropped; `settings-review-fixes` split by topic; unit tests use `vi.stubEnv`.
- **Dependencies removed:** `@xmldom/xmldom`, `remark-gfm`, `@anthropic-ai/tokenizer`, `@testing-library/user-event`, `concurrently`, `wait-on`, `eslint`, `eslint-config-next`, `@vitest/coverage-v8`, `shx`, `motion`, `@radix-ui/react-use-controllable-state`, `react-icons`.
Source lines: 74,983 before, 67,418 after (excluding lockfiles).
The last commit merges #984 (the canvas shell). Where the shell, the classic page or their tests depend on a wire format or signature this branch had changed, main's version wins (export fields of the poll response, `addHistory` signature); where main only extended code this branch restructured, main's change is carried into the new structure (`start_session`, `get_selection`, `prepareNewDiagram`, the diagram context's `requestExport`).
## Testing
- `tsc --noEmit` for the web app, `packages/mcp-server`, its shell and `electron`: clean
- `biome ci`: 0 errors (37 pre-existing warnings)
- Root `vitest run`: 719 passed; `packages/mcp-server` `vitest run`: 372 passed
- `next build`: clean
- Playwright, whole web suite on the dev server (4 workers): 280 tests, 279 passed; `language.spec.ts` "a stale offer to switch without saving does nothing once a message is being sent" failed under parallel load and passed alone, as it does on main
The canvas now fills the window and the chat floats on its right. draw.io is
served from our own origin (public/drawio, downloaded at build time and
checked against the release's SHA-256), so the app can drive the editor
directly:
- every AI change becomes a version card with a thumbnail; compare, restore
or undo it, and Ctrl+Z on the canvas takes an AI change back in one step
- shapes the AI just changed are highlighted on the canvas
- selected shapes appear as a chip and are sent to the model
- draw.io's own simple UI: its toolbar, menus (auto layout, Mermaid, CSV
import) and page tabs; the shape library starts closed
- new start screen, session rename and switcher, open .drawio files
- settings split into Models & keys, Appearance, Advanced and About
- Bedrock in the model settings also takes an API key instead of access keys
- phones switch between canvas and chat
- dark mode uses draw.io's own dark mode, with neutral greys around it
With an external draw.io (NEXT_PUBLIC_DRAWIO_BASE_URL) the features above
that need same origin are off.
The chat logic moved from the 1500-line chat panel into a chat engine plus
small UI components; zustand holds canvas, versions, settings and UI state.
- Add CSS design system tokens (surfaces, borders, animations) to globals.css
- Update dialog.tsx with rounded-2xl, shadow-dialog, refined close button
- Enhance input.tsx with rounded-xl and refined focus states
- Refactor settings-dialog with SettingItem pattern and consistent control sizing
- Refactor model-config-dialog with ConfigSection/ConfigCard helpers
- Replace emerald-* classes with success design tokens
- Remove unused ValidationButton component and scrollState
* feat: add multi-provider model configuration
- Add model config dialog for managing multiple AI providers
- Support for OpenAI, Anthropic, Google, Azure, Bedrock, OpenRouter, DeepSeek, SiliconFlow, Ollama, and AI Gateway
- Add model selector dropdown in chat panel header
- Add API key validation endpoint
- Add custom model ID input with keyboard navigation
- Fix hover highlight in Command component
- Add suggested models for each provider including latest Claude 4.5 series
- Store configuration locally in browser
* feat: improve model config UI and move selector to chat input
- Move model selector from header to chat input (left of send button)
- Add per-model validation status (queued, running, valid, invalid)
- Filter model selector to only show verified models
- Add editable model IDs in config dialog
- Add custom model input field alongside suggested models dropdown
- Fix hover states on provider buttons and select triggers
- Update OpenAI suggested models with GPT-5 series
- Add alert-dialog component for delete confirmation
* refactor: revert shadcn component changes, apply hover fix at usage site
* feat: add AWS credentials support for Bedrock provider
- Add AWS Access Key ID, Secret Access Key, Region fields for Bedrock
- Show different credential fields based on provider type
- Update validation API to handle Bedrock with AWS credentials
- Add region selector with common AWS regions
* fix: reset Test button after validation completes
* fix: reset validation button to Test after success
* fix: complete bedrock support and UI/UX improvements
- Add bedrock to ALLOWED_CLIENT_PROVIDERS for client credentials
- Pass AWS credentials through full chain (headers → API → provider)
- Replace non-existent GPT-5 models with real ones (o1, o3-mini)
- Add accessibility: aria-labels, focus-visible rings, inline errors
- Add more AWS regions (Ohio, London, Paris, Mumbai, Seoul, São Paulo)
- Fix setTimeout cleanup with useRef on component unmount
- Fix TypeScript type consistency in getSelectedAIConfig fallback
* chore: remove unused code
- Remove unused setAccessCodeRequired state in chat-panel.tsx
- Remove unused getSelectedModel export in model-config.ts
* fix: UI/UX improvements for model configuration dialog
- Add gradient header styling with icon badge
- Change Configuration section icon from Key to Settings2
- Add duplicate model detection with warning banner and inline removal
- Filter out already-added models from suggestions dropdown
- Add type-to-confirm for deleting providers with 3+ models
- Enhance delete confirmation dialog with warning icon
- Improve model selector discoverability (show model name + chevron)
- Add truncation for long model names with title tooltip
- Remove AI provider settings from Settings dialog (now in Model Config)
- Extract ValidationButton into reusable component
* fix: prevent duplicate model IDs within same provider
- Block adding model if ID already exists in provider
- Block editing model ID to match existing model in provider
* fix: improve duplicate model ID notifications
- Add toast notification when trying to add duplicate model
- Allow free typing when editing model ID, validate on blur
- Show warning toast instead of blocking input
* fix: improve duplicate model validation UX in config dialog
- Add inline error display for duplicate model IDs
- Show red border on input when error exists
- Validate on blur with shake animation for edit errors
- Prevent saving empty model names
- Clear errors when user starts typing
- Simplify error styling (small red text, no heavy chips)
- Add Close Protection toggle to Settings dialog
- Save setting to localStorage (default: enabled)
- Make beforeunload confirmation conditional
- Settings button now always visible in header
- Add shadcn Switch and Label components
* feat: add markdown rendering for chat messages
- Add react-markdown and @tailwindcss/typography for markdown support
- Use prose styling for assistant message formatting
- Fix Radix ScrollArea viewport horizontal overflow issue
- Add CSS fix for viewport width constraint
* feat: add resizable chat panel
- Replace fixed width layout with react-resizable-panels
- Chat panel can be resized by dragging the handle
- Panel is collapsible with min 15% and max 50% width
- Ctrl+B keyboard shortcut still works for toggle
- Update log-feedback API to find existing chat trace by sessionId and attach score to it
- Update log-save API to create span on existing chat trace instead of standalone trace
- Add thumbs up/down feedback buttons on assistant messages
- Add message regeneration and edit functionality
- Add save dialog with format selection (drawio, png, svg)
- Pass sessionId through components for Langfuse linking
Dayuan Jiang