Achilles — Web App: Stack and chat shell

Frontend

stack — libraries

Shell and render

React Vite TypeScript

Styling and components

Tailwind CSS shadcn/ui · Base UI

Data and state

TanStack Query SSE client

i18n and routing

react-i18next client routing → Auth / Security

Chat shell ↓ below

assistant-ui

structure — files · frontend/src/

frontend/src/
├── routes/      pages under routes — /chat · /account
├── components/  UI primitives — shadcn on Base UI
├── features/    chat — assistant-ui wrapper + our layer
├── i18n/        locales — ru · en
└── lib/         API client · SSE adapter · helpers

Why a thin client

The heavy conversation logic — the flow of the conversation, retrieval, grounding — is run by Query Engine, one API for all surfaces; Web App keeps conversation management (list, retention) and rendering. The frontend receives one SSE answer stream and one conversation schema — and draws them in the shell.

The surface's chat shell — off the shelf

assistant-ui MIT · headless

The web surface doesn't build the chat from scratch: the thread, history, streaming, and “new conversation” come from a mature library. Our domain is custom components inside its thread and a thin conversation-management layer around it, not a rewritten shell.

from the library

thread composer history streaming new conversation auto-scroll markdown a11y

ours — inside the thread

sources [n] grounding states feedback /

ours — around the thread

conversation management retention “new chat” semantics

Two integration seams

SSE → adapter. The Query Engine stream (StreamingResponse · SSE) is consumed by a ChatModelAdapter on the client — the library doesn't dictate the backend, and the LLM keys stay with us.
The skin is ours. We take the headless primitives and style them with our own shadcn tokens on @base-ui/react, not the library's stock Radix theme: the look stays house-style, and we don't pull in a second set of primitives.