# AGENTS.md

This file provides guidance to AI coding agents (Claude Code, Codex, and others) when working with the DeerFlow frontend. It is the source of truth; the sibling `CLAUDE.md` imports it via `@AGENTS.md`.

## Project Overview

DeerFlow Frontend is a Next.js 16 web interface for an AI agent system. It communicates with a LangGraph-based backend to provide thread-based AI conversations with streaming responses, artifacts, and a skills/tools system.

**Stack**: Next.js 16, React 19, TypeScript 5.8, Tailwind CSS 4, pnpm 10.26.2. Requires Node.js 22+ and pnpm 10.26.2+.

### Core dependencies

- **LangGraph SDK** (`@langchain/langgraph-sdk` ^1.5.3) — Agent orchestration and streaming
- **LangChain Core** (`@langchain/core` ^1.1.15) — Fundamental AI building blocks
- **TanStack Query** (`@tanstack/react-query` ^5.90.17) — Server state management
- **UI**: Shadcn UI, MagicUI, React Bits, and Vercel AI SDK elements (generated from registries — see Code Style)

## Commands

| Command          | Purpose                                       |
| ---------------- | --------------------------------------------- |
| `pnpm dev`       | Start the development server with Webpack     |
| `pnpm build`     | Production build                              |
| `pnpm check`     | Lint + type check (run before committing)     |
| `pnpm lint`      | ESLint only                                   |
| `pnpm lint:fix`  | ESLint with auto-fix                          |
| `pnpm format`    | Prettier check (`pnpm format:write` to apply) |
| `pnpm test`      | Run unit tests with Rstest                    |
| `pnpm test:e2e`  | Run E2E tests with Playwright (Chromium)      |
| `pnpm typecheck` | TypeScript type check (`tsc --noEmit`)        |
| `pnpm start`     | Start production server                       |

Unit tests live under `tests/unit/` and mirror the `src/` layout (e.g., `tests/unit/core/api/stream-mode.test.ts` tests `src/core/api/stream-mode.ts`). Powered by Rstest; import source modules via the `@/` path alias.

Webpack is the default development bundler. Use `DEER_FLOW_DEV_BUNDLER=turbo` with `pnpm dev` to opt in to Turbopack when diagnosing a local Next.js bundler issue.

Rstest runs them as two projects (`rstest.config.ts`). `*.test.ts` / `*.test.tsx` run in a plain **node** environment — that is nearly the whole suite, and it is the default for anything that is pure logic. `*.dom.test.ts` / `*.dom.test.tsx` run in **happy-dom**, for tests that need a document: hooks driven through `renderHook` from `@testing-library/react`, and components. Keep the split — a DOM environment costs roughly 3x the runtime of the node suite, so tests that do not render should not opt into it. A hook whose behavior only exists under real React (effect ordering, cleanup on unmount, re-render on store change) belongs in a `.dom.test.*` file rather than a node test that mocks `react` itself.

E2E tests live under `tests/e2e/` and use Playwright with Chromium. They mock all backend APIs via `page.route()` network interception and test real page interactions (navigation, chat input, streaming responses). Config: `playwright.config.ts`.

## Architecture

```
Frontend (Next.js) ──▶ LangGraph SDK ──▶ LangGraph Backend (lead_agent)
                                              ├── Sub-Agents
                                              └── Tools & Skills
```

The frontend is a stateful chat application. Users create **threads** (conversations), send messages, set thread-scoped `/goal` completion conditions, and receive streamed AI responses. The backend orchestrates agents that can produce **artifacts** (files/code), **todos**, and goal state updates.

### Source Layout (`src/`)

- **`app/`** — Next.js App Router. Routes include `/` (landing), `/showcase/[thread_id]` (allowlisted public read-only demos), `/workspace/chats/[thread_id]` (authenticated chat), `/workspace/agents/[agent_name]` and `/workspace/agents/new` (custom agents), `/artifacts/view` (chrome-free window that renders one markdown artifact with the panel's own renderer), `/blog/…`, the `(auth)/{login,setup,auth/callback}` flow, `/[lang]/docs/…`, and `/api/…` route handlers (e.g. `/api/memory`).
- **`components/`** — React components:
  - `ui/` — Shadcn UI primitives (auto-generated, ESLint-ignored)
  - `ai-elements/` — Vercel AI SDK elements (auto-generated, ESLint-ignored)
  - `workspace/` — Chat page components (messages, artifacts, settings)
  - `landing/` — Landing page sections
  - `docs/` — Docs / MDX rendering components
- **`core/`** — Business logic, the heart of the app. Domains include `threads/` (creation, streaming, state), `api/` (LangGraph client singleton), `agents/` (custom agents), `subagents/` (runtime worker catalog and administrator mutations), `auth/` (authentication), `artifacts/`, `channels/` (IM connections), `integrations/` (managed third-party integration status/install clients such as Lark CLI), `i18n/` (en-US, zh-CN), `settings/`, `memory/`, `skills/`, `messages/`, `mcp/`, `models/`, `input-polish/` (pre-send draft rewrite API), `voice-input/` (browser speech-recognition helpers), `suggestions/`, `tasks/`, `todos/`, `tools/`, `workspace-changes/` (run-scoped changed-file summaries and diff fetching), `config/`, `notification/`, `blog/`, plus rendering helpers (`rehype/`, `streamdown/`) and `utils/`.
- **`hooks/`** — Shared React hooks
- **`lib/`** — Utilities (`cn()` from clsx + tailwind-merge)
- **`content/`** — MDX content (blog posts, docs) rendered by the app
- **`styles/`** — Global CSS with Tailwind v4 `@import` syntax and CSS variables for theming
- **`typings/`** — Ambient TypeScript declarations
- Root files: `env.js` (env validation), `mdx-components.ts` (MDX component map)

More specific `AGENTS.md` files under `src/` contain the frontend sections split from this file.

## Code Style

- **Imports**: Enforced ordering (builtin → external → internal → parent → sibling), alphabetized, newlines between groups. Use inline type imports: `import { type Foo }`.
- **Unused variables**: Prefix with `_`.
- **Class names**: Use `cn()` from `@/lib/utils` for conditional Tailwind classes.
- **Path alias**: `@/*` maps to `src/*`.
- **Components**: `ui/` and `ai-elements/` are generated from registries (Shadcn, MagicUI, React Bits, Vercel AI SDK) — don't manually edit these.

## Environment

Backend API URLs are optional; an nginx proxy is used by default:

```
NEXT_PUBLIC_BACKEND_BASE_URL=http://localhost:8001
NEXT_PUBLIC_LANGGRAPH_BASE_URL=http://localhost:8001/api
```

Leave these unset for the standard `make dev` / Docker flow, where nginx serves the public `/api/langgraph/*` prefix and rewrites it to Gateway's native `/api/*` routes.

To reach a dev server on anything other than localhost — a LAN address, or a proxied hostname — list the host in `DEER_FLOW_DEV_ALLOWED_ORIGINS` (comma-separated; a full URL is reduced to its host). It feeds Next's `allowedDevOrigins`, which gates `/_next/*`, fonts, and HMR. Without it those requests get a 403 and the page renders server-side but never hydrates, so nothing on it — including the login form — responds. Development only; production builds ignore it.

## Resources

- [LangGraph Documentation](https://langchain-ai.github.io/langgraph/)
- [LangChain Core Concepts](https://js.langchain.com/docs/concepts)
- [TanStack Query Documentation](https://tanstack.com/query/latest)
- [Next.js App Router](https://nextjs.org/docs/app)

## Contributing

When adding features:

1. Follow the established `src/` structure
2. Add TypeScript types and proper error handling
3. Write unit tests under `tests/unit/` (`pnpm test`) and E2E tests under `tests/e2e/` (`pnpm test:e2e`)
4. Run `pnpm check` before committing
5. Update this `AGENTS.md` when architecture, commands, or conventions change

Route asset budgets are enforced with `pnpm perf:check`. The command measures
`/login` from a normal production build, then builds in static-demo mode for the
fixture-backed workspace routes. It starts the production server on temporary local
ports, measures the unique JavaScript and CSS files referenced by representative
routes, writes the detailed result to `.next/performance-results.json`, and compares
totals with `performance-budgets.json`. Fix route ownership or split points when a
budget fails; do not raise a ceiling without documenting and reviewing the measured
regression.

Chat archive is a thread metadata flag (`deerflow_archived === true`), independent
of run status. Sidebar and Chats explicitly request the Gateway's optional
`archived` filter through `searchThreadsByArchive`; the SDK drops this extension,
so use the authenticated REST fetcher. Static demos retain SDK fixture queries.
`core/threads/archive.ts` waits for the write, cancels stale reads, merges only the
owned flag into metadata snapshots, then restarts metadata reads and resets list
pagination. Keep both default and Custom Agent header restore controls in sync.
Pin/archive responses must not merge unrelated metadata flags: out-of-order
organization requests can otherwise roll back each other's confirmed state.
Run-created optimistic snapshots have no archive flag: refresh archive-filtered
lists from the server instead of inserting those snapshots into either view.