YuJitang eab7ae3d62
feat: stream subagent token usage to header via terminal task events (#2882)
* feat: real-time subagent token usage display in header and per-turn

Backend:
- Persist subagent token usage to AIMessage.usage_metadata via
  TokenUsageMiddleware, so accumulateUsage() naturally includes
  subagent tokens without frontend state management
- Cache subagent usage by tool_call_id in task_tool, write back
  to the dispatching AIMessage on next model response
- Emit subagent token usage on all terminal task events
  (task_completed, task_failed, task_cancelled, task_timed_out)
- Report subagent usage to parent RunJournal for API totals
- Search backward from ToolMessage to find dispatching AIMessage
  for correct multi-tool-call attribution

Frontend:
- Remove subagentUsage state, custom event handling, and prop
  threading — subagent tokens are now embedded in message metadata
- Simplify selectHeaderTokenUsage (no subagentUsage parameter)
- Per-turn inline badges show turn-specific usage via message
  accumulation
- Remove isLoading guard from MessageTokenUsageList for dynamic
  updates during streaming

* fix: prevent header token double counting from baseline reset race

onFinish, onError, and thread-switch useEffect all reset
pendingUsageBaselineMessageIdsRef to an empty Set. If
thread.isLoading is still true on the next render, all messages
pass the getMessagesAfterBaseline filter and their tokens are
added to backendUsage (which already includes them), causing
the header to display up to 2× the actual token count.

Capture current message IDs instead of using an empty Set so
that getMessagesAfterBaseline correctly returns no pending
messages even if thread.isLoading lags behind the stream end.

* fix: write back subagent tokens for all concurrent task tool calls

TokenUsageMiddleware only processed messages[-2], so when a
single model response dispatched multiple task tool calls only
the last ToolMessage had its cached subagent usage written back
to the dispatch AIMessage.usage_metadata. Earlier tasks' usage
stayed in _subagent_usage_cache indefinitely (leak) and never
appeared in the per-turn inline token display.

Walk backward through all consecutive ToolMessages before the
new AIMessage, and accumulate updates targeting the same
dispatch message into one state update so overlapping writes
don't clobber each other.

* fix: clean up subagent usage cache entry on task cancellation

When a task_tool invocation is cancelled via CancelledError, any
cached subagent usage entry leaked because the TokenUsageMiddleware
writeback path never fires after cancellation. Pop the cache entry
before re-raising to prevent unbounded growth of the module-level
_subagent_usage_cache dict.

* fix: address token usage review feedback

* fix: handle missing config for subagent usage cache

---------

Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
2026-05-13 23:52:19 +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.