# Technical Decisions

## 2026-07-14: Client-rendered Web Foundation

**Context**: MyGO needs a browser client now and native clients later. The Web application must share the versioned REST API instead of introducing browser-only server logic.

**Decisions**:

| Area | Choice | Guidance |
|------|--------|----------|
| Rendering | Pure client-side rendered SPA | Vite emits static assets; do not introduce SSR, React Server Components, or a Node API server. |
| Application stack | React, strict TypeScript, React Router, and TanStack Query | Keep routing and remote-data state explicit and client-side. |
| UI system | Ant Design plus Tailwind CSS 4 | Ant Design owns reusable controls and theme tokens; Tailwind initially owns layout, spacing, and responsive utilities. |
| Dependency policy | Install capabilities when their feature starts | Keep API generation, transfer, virtualization, drag-and-drop, test, and preview libraries deferred in `docs/web/roadmap.md`. |

**Consequences**:
- The Web and future native clients consume the same client-neutral API contracts.
- MyGO or a reverse proxy may host `web/dist` with an SPA fallback without changing the rendering model.
- MyGO domain components own file-browser behavior and must not depend on Ant Design request behavior for business logic.

## 2026-07-14: Browser Authentication and Root File Workflow

**Context**: The first Web milestone needs to exercise the existing login, file
list, upload, and download APIs without committing to the later directory,
account, admin, or large-transfer designs.

**Decisions**:

| Area | Choice | Guidance |
|------|--------|----------|
| API topology | Same-origin `/api/v1` | Vite proxies `/api` to the local Go server. Production uses a same-origin reverse proxy; the milestone does not add CORS or Go static hosting. |
| Browser session | Token pair in `sessionStorage` | Reloading the tab preserves the session, while closing the tab clears it. Do not add persistent login until the token transport design is revisited. |
| Token refresh | Refresh once after a protected request returns 401 | Share one in-flight refresh across concurrent failures, store the rotated pair, and retry each request once. Clear the session if refresh or the retry fails. |
| File scope | Root directory only | List root entries, upload one file to root, and download files. Show directories as non-interactive rows. |
| Transfer model | Browser `FormData` upload and authenticated Blob download | This is intentionally limited to the small-file milestone; progress, streaming-to-disk, chunking, resume, and queues remain deferred. |

**Consequences**:
- The API client owns bearer headers, error parsing, refresh coordination, and
  session invalidation; pages consume operation-specific functions.
- TanStack Query caches are cleared whenever an authenticated session ends so
  one user cannot see another user's cached file metadata.
- The file picker is independent of Ant Design upload request behavior, keeping
  transfer policy in MyGO code.
- Handwritten TypeScript wire types remain temporary until an OpenAPI contract
  is available.

## 2026-07-14: Project-local Headless Browser Tooling

**Context**: Browser behavior needs deterministic E2E coverage and interactive
agent debugging inside a long-lived headless Debian Incus container. Tooling
should remain reproducible without placing browser binaries or generated
artifacts in a developer's home directory.

**Decisions**:

| Area | Choice | Guidance |
|------|--------|----------|
| Regression tests | Playwright Test with bundled Chromium | Keep browser E2E tests separate from `npm run check` because browser installation is an explicit environment setup step. |
| Agent debugging | Official Playwright MCP over project-scoped STDIO | Codex starts the locked local package from `.codex/config.toml`; do not use a global install, an `@latest` npx invocation, or a listening MCP service. |
| Browser state | Headless, isolated, and sandboxed | Use bundled Chromium, discard the MCP profile after each session, and retain the Chromium sandbox supported by the Incus environment. |
| Local resources | Repository `.cache/` and `.artifacts/` directories | `mise.toml` defines the portable npm and browser cache paths. Generated resources remain ignored by Git. |
| Browser versions | Install both locked Playwright revisions | The stable test runner and current MCP package require different Chromium revisions; do not force either package onto an unsupported executable. |

**Consequences**:
- Debian browser libraries are installed once in the Incus container root
  filesystem; npm packages, browsers, traces, screenshots, and MCP output stay
  project-scoped.
- A fresh environment runs `npm ci`, the system dependency installer, and both
  browser install scripts before browser tests or MCP debugging.
- Browser failures can retain traces, screenshots, and video under
  `.artifacts/playwright/` without adding generated files to source control.