AGENTS.md

1# AGENTS.md
2 
3This 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`.
4 
5## Project Overview
6 
7DeerFlow 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.
8 
9**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+.
10 
11### Core dependencies
12 
13- **LangGraph SDK** (`@langchain/langgraph-sdk` ^1.5.3) — Agent orchestration and streaming
14- **LangChain Core** (`@langchain/core` ^1.1.15) — Fundamental AI building blocks
15- **TanStack Query** (`@tanstack/react-query` ^5.90.17) — Server state management
16- **UI**: Shadcn UI, MagicUI, React Bits, and Vercel AI SDK elements (generated from registries — see Code Style)
17 
18## Commands
19 
20| Command          | Purpose                                           |
21| ---------------- | ------------------------------------------------- |
22| `pnpm dev`       | Dev server with Turbopack (http://localhost:3000) |
23| `pnpm build`     | Production build                                  |
24| `pnpm check`     | Lint + type check (run before committing)         |
25| `pnpm lint`      | ESLint only                                       |
26| `pnpm lint:fix`  | ESLint with auto-fix                              |
27| `pnpm format`    | Prettier check (`pnpm format:write` to apply)     |
28| `pnpm test`      | Run unit tests with Rstest                        |
29| `pnpm test:e2e`  | Run E2E tests with Playwright (Chromium)          |
30| `pnpm typecheck` | TypeScript type check (`tsc --noEmit`)            |
31| `pnpm start`     | Start production server                           |
32 
33Unit 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.
34 
35Rstest 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.
36 
37E2E 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`.
38 
39## Architecture
40 
41```
42Frontend (Next.js) ──▶ LangGraph SDK ──▶ LangGraph Backend (lead_agent)
43                                              ├── Sub-Agents
44                                              └── Tools & Skills
45```
46 
47The 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.
48 
49### Source Layout (`src/`)
50 
51- **`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), `/blog/…`, the `(auth)/{login,setup,auth/callback}` flow, `/[lang]/docs/…`, and `/api/…` route handlers (e.g. `/api/memory`).
52- **`components/`** — React components:
53  - `ui/` — Shadcn UI primitives (auto-generated, ESLint-ignored)
54  - `ai-elements/` — Vercel AI SDK elements (auto-generated, ESLint-ignored)
55  - `workspace/` — Chat page components (messages, artifacts, settings)
56  - `landing/` — Landing page sections
57  - `docs/` — Docs / MDX rendering components
58- **`core/`** — Business logic, the heart of the app. Domains include `threads/` (creation, streaming, state), `api/` (LangGraph client singleton), `agents/` (custom agents), `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/`.
59- **`hooks/`** — Shared React hooks
60- **`lib/`** — Utilities (`cn()` from clsx + tailwind-merge)
61- **`content/`** — MDX content (blog posts, docs) rendered by the app
62- **`styles/`** — Global CSS with Tailwind v4 `@import` syntax and CSS variables for theming
63- **`typings/`** — Ambient TypeScript declarations
64- Root files: `env.js` (env validation), `mdx-components.ts` (MDX component map)
65 
66More specific `AGENTS.md` files under `src/` contain the frontend sections split from this file.
67 
68## Code Style
69 
70- **Imports**: Enforced ordering (builtin → external → internal → parent → sibling), alphabetized, newlines between groups. Use inline type imports: `import { type Foo }`.
71- **Unused variables**: Prefix with `_`.
72- **Class names**: Use `cn()` from `@/lib/utils` for conditional Tailwind classes.
73- **Path alias**: `@/*` maps to `src/*`.
74- **Components**: `ui/` and `ai-elements/` are generated from registries (Shadcn, MagicUI, React Bits, Vercel AI SDK) — don't manually edit these.
75 
76## Environment
77 
78Backend API URLs are optional; an nginx proxy is used by default:
79 
80```
81NEXT_PUBLIC_BACKEND_BASE_URL=http://localhost:8001
82NEXT_PUBLIC_LANGGRAPH_BASE_URL=http://localhost:8001/api
83```
84 
85Leave 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.
86 
87To 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.
88 
89## Resources
90 
91- [LangGraph Documentation](https://langchain-ai.github.io/langgraph/)
92- [LangChain Core Concepts](https://js.langchain.com/docs/concepts)
93- [TanStack Query Documentation](https://tanstack.com/query/latest)
94- [Next.js App Router](https://nextjs.org/docs/app)
95 
96## Contributing
97 
98When adding features:
99 
1001. Follow the established `src/` structure
1012. Add TypeScript types and proper error handling
1023. Write unit tests under `tests/unit/` (`pnpm test`) and E2E tests under `tests/e2e/` (`pnpm test:e2e`)
1034. Run `pnpm check` before committing
1045. Update this `AGENTS.md` when architecture, commands, or conventions change
105 
106Route asset budgets are enforced with `pnpm perf:check`. The command measures
107`/login` from a normal production build, then builds in static-demo mode for the
108fixture-backed workspace routes. It starts the production server on temporary local
109ports, measures the unique JavaScript and CSS files referenced by representative
110routes, writes the detailed result to `.next/performance-results.json`, and compares
111totals with `performance-budgets.json`. Fix route ownership or split points when a
112budget fails; do not raise a ceiling without documenting and reviewing the measured
113regression.
114