Xinmin Zeng 8d2e55a05f
fix(subagent): structured subagent_status field over text parsing (#3146) (#3154)
* fix(subagent): structured subagent_status field over text parsing

Closes #3146.

## Why

The frontend used to derive subtask card state by string-matching the
leading text of the `task` tool's result. That contract surface was
fragile — `#3107` BUG-007 and the `#3131` review both surfaced cases
where new backend wording (`Task cancelled by user.`,
`Task polling timed out after N minutes`, `ToolErrorHandlingMiddleware`
exception wrappers) silently broke the card lifecycle. The frontend
fallback kept growing more prefixes; any future rewording would break
it again.

## Design

1. **Backend → frontend contract**: `ToolMessage.additional_kwargs`
   carries `subagent_status` (one of `completed | failed | cancelled |
   timed_out | polling_timed_out`) and an optional `subagent_error`
   blob. The frontend prefers it over parsing `content`.

2. **Centralised stamping, not 8 sprinkled stamps**: rather than have
   each of `task_tool.py`'s 5 normal-return + 3 pre-execution `Error:`
   paths remember to set `additional_kwargs`, `ToolErrorHandlingMiddleware`
   stamps the field after every task-tool call. Adding a new return
   path in `task_tool.py` cannot now skip the stamp.

3. **Cross-language contract fixture**: the prefix→status mapping is
   the one piece both sides must agree on. The shared fixture at
   `contracts/subagent_status_contract.json` lists every backend return
   string, the expected status, and what the error substring should
   contain. Backend test (`backend/tests/test_subagent_status_contract.py`)
   and frontend test (`frontend/tests/unit/core/tasks/subtask-result.test.ts`)
   both load that fixture and assert the same cases. A wording drift on
   either side fails the matching language's test.

4. **Round-trip serialisation pinned**: the round-trip test asserts
   `ToolMessage.model_dump_json()` → `model_validate_json()` preserves
   `additional_kwargs.subagent_status`. Catches the case where a future
   LangChain or Pydantic upgrade silently strips unknown kwargs.

5. **Frontend status collapse documented**: the backend has five status
   values, the frontend card has three (`completed | failed |
   in_progress`). `cancelled` / `timed_out` / `polling_timed_out` all
   collapse to `failed` with the original status preserved in `error`.
   `parseSubtaskResult` returns `in_progress` for unknown values so a
   backend that ships a new enum variant before the frontend upgrades
   degrades to the legacy prefix fallback instead of getting pinned.

## Changes

Backend:
- `deerflow.subagents.status_contract` — new module exporting
  `SUBAGENT_STATUS_KEY`, `SUBAGENT_ERROR_KEY`,
  `SUBAGENT_STATUS_VALUES`, `extract_subagent_status(content)`, and
  `make_subagent_additional_kwargs(status, error)`.
- `ToolErrorHandlingMiddleware`: new `_stamp_task_subagent_status`
  helper centralises the stamp; `wrap_tool_call` / `awrap_tool_call`
  stamp on the success path; `_build_error_message` stamps on the
  wrapper path (carrying `ExcClass: detail` into `subagent_error`).
  Non-task tools are untouched.
- New tests: `test_subagent_status_contract.py` (19 cases from the
  shared fixture + status-enum / blank-error / unknown-status
  rejection) and `test_tool_error_handling_subagent_stamp.py`
  (middleware integration: terminal-content stamps, non-terminal
  doesn't, non-task tools untouched, async path mirrors sync,
  existing additional_kwargs survive, JSON round-trip preserved).

Frontend:
- `parseSubtaskResult(text, additionalKwargs?)` — prefers the
  structured stamp; falls back to the legacy prefix matcher for
  historical threads / unknown future status values.
- `STRUCTURED_STATUS_TO_SUBTASK` documents the five→three collapse.
- `message-list.tsx` passes `message.additional_kwargs` through.
- `subtask-result.test.ts` adds a structured-status block + a
  fixture-driven contract block; legacy prefix tests stay green for
  the fallback path.

Contract:
- `contracts/subagent_status_contract.json` — single source of truth
  both languages load. Whitespace variants, varied N for polling
  timeouts, the 3 pre-execution `Error:` returns task_tool produces,
  and the middleware wrapper shape are all in there.

## Test plan
- `make lint` clean (backend + frontend).
- `pytest tests/test_subagent_status_contract.py
   tests/test_tool_error_handling_subagent_stamp.py` → 37 passed.
- `pnpm test --run` → 103 passed (was 76, +27 new).

## Migration / fallback retirement

The text-prefix fallback stays in place until backend telemetry shows
the frontend never hits it for newly produced messages. At that point
a follow-up PR can drop the prefix branches and keep only the
structured-status branch.

Refs: bytedance/deer-flow#3138 (split summary), #3107 (origin), #3131
(prior prefix-only fix), #3146 (this issue).

* fix(subtask): back-fill result/error from text when structured status present

Three follow-ups on the PR #3154 review:

1. `readStructuredStatus` no longer short-circuits the prefix parse.
   The backend currently stamps only the `subagent_status` enum value;
   the human-facing `result` body and wrapped-error message still live
   in `ToolMessage.content`. Dropping the text parse meant successful
   tasks rendered empty completed pills and wrapped failures lost their
   diagnostic. Now both shapes get composed: structured status wins,
   `result`/`error` come from text when both sides agree, and a lying
   success body under a `failed` stamp is dropped instead of leaking.

2. Replace the ESM-incompatible `__dirname` fixture lookup in
   subtask-result.test.ts with `fileURLToPath(new URL(..., import.meta.url))`.
   The frontend package is `"type": "module"`, so the previous path
   would have thrown at runtime if anything ever changed under the
   contract directory.

3. Drop the `$schema` reference from contracts/subagent_status_contract.json
   pointing at a file that doesn't exist in the tree.

Three new tests cover the structured + text composition: completed
back-fills the success body, failed back-fills the wrapper text, and
unrecognised content under a `failed` stamp stays empty rather than
echoing noise.
2026-06-07 22:49:55 +08:00
..
2026-01-14 09:58:53 +08:00
2026-01-24 19:38:08 +08:00
2026-02-10 22:07:25 +08:00

DeerFlow Frontend

Like the original DeerFlow 1.0, we would love to give the community a minimalistic and easy-to-use web interface with a more modern and flexible architecture.

Tech Stack

Quick Start

Prerequisites

  • Node.js 22+
  • pnpm 10.26.2+

Installation

# Install dependencies
pnpm install

# Copy environment variables
cp .env.example .env
# Edit .env with your configuration

Development

# Start development server
pnpm dev

# The app will be available at http://localhost:3000

Build & Test

# Type check
pnpm typecheck

# Check formatting
pnpm format

# Apply formatting
pnpm format:write

# Lint
pnpm lint

# Run unit tests
pnpm test

# One-time setup: install Playwright Chromium browser
pnpm exec playwright install chromium

# Run E2E tests (builds and starts production server automatically)
pnpm test:e2e

# Build for production
pnpm build

# Start production server
pnpm start

Site Map

├── /                    # Landing page
├── /chats               # Chat list
├── /chats/new           # New chat page
└── /chats/[thread_id]   # A specific chat page

Configuration

Environment Variables

Key environment variables (see .env.example for full list):

# Backend API URL (optional, uses local Next.js/nginx proxy by default)
NEXT_PUBLIC_BACKEND_BASE_URL="http://localhost:8001"
# LangGraph-compatible API URL (optional, uses local Next.js/nginx proxy by default)
NEXT_PUBLIC_LANGGRAPH_BASE_URL="http://localhost:8001/api"

Project Structure

tests/
├── e2e/                    # E2E tests (Playwright, Chromium, mocked backend)
└── unit/                   # Unit tests (mirrors src/ layout)
src/
├── app/                    # Next.js App Router pages
│   ├── api/                # API routes
│   ├── workspace/          # Main workspace pages
│   └── mock/               # Mock/demo pages
├── components/             # React components
│   ├── ui/                 # Reusable UI components
│   ├── workspace/          # Workspace-specific components
│   ├── landing/            # Landing page components
│   └── ai-elements/        # AI-related UI elements
├── core/                   # Core business logic
│   ├── api/                # API client & data fetching
│   ├── artifacts/          # Artifact management
│   ├── config/              # App configuration
│   ├── i18n/               # Internationalization
│   ├── mcp/                # MCP integration
│   ├── messages/           # Message handling
│   ├── models/             # Data models & types
│   ├── settings/           # User settings
│   ├── skills/             # Skills system
│   ├── threads/            # Thread management
│   ├── todos/              # Todo system
│   └── utils/              # Utility functions
├── hooks/                  # Custom React hooks
├── lib/                    # Shared libraries & utilities
├── server/                 # Server-side code
│   └── better-auth/        # Authentication setup and session helpers
└── styles/                 # Global styles

Scripts

Command Description
pnpm dev Start development server with Turbopack
pnpm build Build for production
pnpm start Start production server
pnpm test Run unit tests with Vitest
pnpm test:e2e Run E2E tests with Playwright
pnpm format Check formatting with Prettier
pnpm format:write Apply formatting with Prettier
pnpm lint Run ESLint
pnpm lint:fix Fix ESLint issues
pnpm typecheck Run TypeScript type checking
pnpm check Run both lint and typecheck

Development Notes

  • Uses pnpm workspaces (see packageManager in package.json)
  • Turbopack enabled by default in development for faster builds
  • Environment validation can be skipped with SKIP_ENV_VALIDATION=1 (useful for Docker)
  • Backend API URLs are optional; nginx proxy is used by default in development

License

MIT License. See LICENSE for details.