ReasonFlow

Imported from namanxdev/ReasonFlow (AGENTS.md). Install upstream with npx skills add namanxdev/ReasonFlow. Copyright stays with the author.

ReasonFlow — Agent Guide

This document provides comprehensive information for AI coding agents working on the ReasonFlow project.

Project Overview

ReasonFlow is an autonomous inbox AI agent that helps professionals manage email overload. Unlike standard email clients that simply list unread messages, ReasonFlow actively works on emails by:

• Classifying incoming emails by intent (inquiry, meeting request, complaint, etc.)
• Retrieving relevant context from past emails, CRM data, and calendar
• Generating draft responses using Google Gemini via LangChain
• Routing low-confidence drafts to humans for approval
• Dispatching approved responses automatically

The core philosophy: "Stop writing emails. Start approving them."

Technology Stack

Backend

Frontend

Project Structure

ReasonFlow/
├── backend/                    # FastAPI backend
│   ├── app/
│   │   ├── agent/              # LangGraph workflow engine
│   │   │   ├── nodes/          # Classification, retrieval, decision, generation, review
│   │   │   ├── state/          # Agent state definitions (TypedDict)
│   │   │   └── tools/          # Tool manager + tool implementations
│   │   ├── api/                # FastAPI routes + middleware
│   │   │   ├── middleware/     # Error handling, rate limiting
│   │   │   └── routes/         # Auth, emails, drafts, traces, metrics, calendar, CRM
│   │   ├── core/               # Config, database, security, dependencies
│   │   ├── integrations/       # Gmail, Calendar, CRM clients
│   │   │   ├── calendar/
│   │   │   ├── crm/
│   │   │   └── gmail/
│   │   ├── llm/                # Gemini client + prompts (via LangChain)
│   │   ├── models/             # SQLAlchemy models
│   │   ├── retrieval/          # Embeddings + vector search
│   │   ├── schemas/            # Pydantic request/response schemas
│   │   └── services/           # Business logic layer
│   ├── alembic/                # Database migrations
│   ├── tests/                  # Test suite
│   │   ├── integrations/       # Integration tests
│   │   └── services/           # Service unit tests
│   ├── pyproject.toml          # Project metadata and dependencies
│   ├── requirements.txt        # Dependency list
│   └── .env.example            # Environment variable template
│
├── frontend/                   # Next.js 14+ frontend
│   ├── src/
│   │   ├── app/                # App Router pages
│   │   │   ├── (auth)/         # Login, register
│   │   │   ├── (dashboard)/    # Inbox, drafts, metrics, traces
│   │   │   ├── auth/gmail/callback/  # OAuth callback
│   │   │   └── [feature]/      # Feature pages (inbox, drafts, calendar, crm, traces)
│   │   ├── components/         # UI components per feature
│   │   │   ├── draft-review/
│   │   │   ├── inbox/
│   │   │   ├── layout/
│   │   │   ├── metrics/
│   │   │   ├── trace-viewer/
│   │   │   └── ui/             # shadcn/ui base components
│   │   ├── hooks/              # React Query hooks
│   │   ├── lib/                # API client, utilities
│   │   ├── providers/          # QueryProvider, theme providers
│   │   ├── stores/             # Zustand state stores
│   │   └── types/              # TypeScript interfaces
│   ├── components.json         # shadcn/ui configuration
│   ├── next.config.ts          # Next.js configuration
│   └── package.json            # NPM dependencies
│
├── docs/                       # Documentation
│   ├── architecture/           # System design docs
│   └── features/               # Feature specifications
│
├── Makefile                    # Build and dev commands
└── README.md                   # Project overview

Build and Development Commands

Quick Start

# Start both backend and frontend concurrently
make dev

Individual Services

# Backend only
make backend
# Or directly:
cd backend && uvicorn app.main:app --reload --host 0.0.0.0 --port 8000

# Frontend only
make frontend
# Or directly:
cd frontend && npm run dev

Installation

# Install all dependencies
make install

# Or install separately:
# Backend
cd backend && pip install -e ".[dev]"

# Frontend
cd frontend && npm install

Database Migrations

cd backend

# Create a new migration
alembic revision --autogenerate -m "description"

# Apply migrations
alembic upgrade head

# Rollback one revision
alembic downgrade -1

# View current version
alembic current

Cleanup

# Kill running dev processes (Windows)
make clean

Testing

Backend Tests

cd backend

# Run all tests
pytest

# Run with coverage
pytest --cov=app --cov-report=html

# Run specific test file
pytest tests/test_node_classify.py

# Run with verbose output
pytest -v

Test Structure

• tests/conftest.py — Shared pytest fixtures
• tests/test_*.py — Unit tests for individual components
• tests/services/ — Service layer tests
• tests/integrations/ — Integration tests for external services

Key Fixtures

• sample_email — Minimal email dict for agent testing
• base_state — Minimal AgentState for node tests
• mock_db — Async-compatible SQLAlchemy session mock

Code Style Guidelines

Python (Backend)

We use Ruff for linting and formatting with these settings:

[tool.ruff]
target-version = "py311"
line-length = 100

[tool.ruff.lint]
select = ["E", "F", "I", "N", "W", "UP"]

Key conventions:

• Line length: 100 characters
• Imports: Sorted with isort rules (E, F, I, N, W, UP)
• Type hints: Use from __future__ import annotations for forward references
• Async: Prefer async/await for I/O operations
• Docstrings: Google-style docstrings for public functions

Run linting:

cd backend
ruff check .
ruff check . --fix  # Auto-fix issues

TypeScript (Frontend)

• Strict mode: Enabled in tsconfig.json
• Components: Use functional components with explicit return types
• Imports: Use @/ alias for project imports
• Formatting: Follow shadcn/ui conventions

Environment Setup

Required Environment Variables

Create backend/.env from backend/.env.example:

# Database
DATABASE_URL=postgresql+asyncpg://postgres:postgres@localhost:5432/reasonflow

# Google Gemini API
GEMINI_API_KEY=your-gemini-api-key-here

# Gmail OAuth
GMAIL_CLIENT_ID=your-gmail-client-id
GMAIL_CLIENT_SECRET=your-gmail-client-secret
GMAIL_REDIRECT_URI=http://localhost:8000/api/v1/auth/gmail/callback

# JWT
JWT_SECRET_KEY=your-super-secret-jwt-key-change-in-production
JWT_ALGORITHM=HS256
JWT_EXPIRATION_MINUTES=30

# CORS
CORS_ORIGINS=["http://localhost:3000"]

# App
APP_ENV=development
APP_DEBUG=true

Create frontend/.env.local from frontend/.env.example:

NEXT_PUBLIC_API_URL=http://localhost:8000

External Services Required

1. PostgreSQL with pgvector extension
2. Google Gemini API key
3. Gmail OAuth credentials (for email integration)

Architecture Overview

Agent Workflow (LangGraph)

The core email processing pipeline consists of 7 nodes:

START → classify → retrieve → decide → [execute] → generate → review → [dispatch/human_queue] → END

1. classify — Classify email intent (inquiry, meeting_request, complaint, etc.)
2. retrieve — Fetch relevant context from vector store
3. decide — Decide which tools to invoke
4. execute — Execute selected tools (optional, based on decision)
5. generate — Generate draft response using Gemini
6. review — Review confidence and determine if human approval needed
7. dispatch — Send approved responses OR human_queue — Queue for review

Conditional routing:

• Spam with confidence >= 0.8 → short-circuit to END
• No tools selected → skip execute node
• requires_approval=True → route to human_queue

Database Schema

Core Tables:

• users — User accounts with OAuth tokens
• emails — Emails from Gmail with classification and status
• agent_logs — Step-by-step execution traces
• tool_executions — Individual tool call records
• embeddings — Vector embeddings for similarity search (pgvector)

Email Status Enum: pending → processing → drafted/needs_review → approved → sent

API Structure

All API routes under /api/v1/:

Frontend Structure

Routing (Next.js App Router):

• / → redirects to /inbox
• /inbox — Email inbox view
• /drafts — Draft review queue
• /traces — Execution traces list
• /traces/[traceId] — Individual trace viewer
• /metrics — Analytics dashboard
• /calendar — Calendar integration view
• /crm — CRM contacts view
• /login, /register — Authentication

State Management:

• Zustand: Client-side UI state (auth, filters, modals)
• TanStack Query: Server state (emails, drafts, metrics, traces)

Security Considerations

1. Authentication: JWT-based with configurable expiration
2. Authorization: OAuth tokens encrypted at rest using Fernet
3. Rate Limiting: In-memory sliding window (60 req/min default)
4. Input Validation: Pydantic on all API endpoints
5. CORS: Restricted to configured origins
6. Secrets: Stored exclusively in environment variables
7. SQL Injection: Prevented via SQLAlchemy ORM

Security Headers

FastAPI includes security middleware:

• CORS validation
• Rate limiting per IP/user
• Request size limits

Common Tasks

Adding a New Agent Node

1. Create file in backend/app/agent/nodes/my_node.py
2. Implement async function: async def my_node(state: AgentState) -> dict[str, Any]
3. Add to backend/app/agent/nodes/__init__.py
4. Register in backend/app/agent/graph.py:
   • Add import
   • Add graph.add_node("my_node", my_node)
   • Add edges with graph.add_edge() or graph.add_conditional_edges()
5. Add tests in backend/tests/test_node_my_node.py

Adding a New API Endpoint

1. Create or edit file in backend/app/api/routes/
2. Add Pydantic schemas in backend/app/schemas/
3. Include router in backend/app/api/router.py
4. Add tests in backend/tests/services/ or backend/tests/integrations/

Adding a Frontend Page

1. Create route directory in frontend/src/app/my-page/
2. Add page.tsx with component
3. Add API hooks in frontend/src/hooks/
4. Add components in frontend/src/components/my-page/
5. Update navigation in layout components

Adding a Database Migration

cd backend
alembic revision --autogenerate -m "add new table"
# Edit generated migration if needed
alembic upgrade head

Performance Targets

Troubleshooting

Common Issues

Database connection errors:

• Verify PostgreSQL is running
• Check DATABASE_URL in .env
• Ensure pgvector extension is installed

Gemini API errors:

• Verify GEMINI_API_KEY is set and valid
• Check Google Cloud Console for quota limits

OAuth failures:

• Verify Gmail OAuth credentials
• Check redirect URI matches exactly

Debug Mode

Set APP_DEBUG=true in backend .env to enable:

• Swagger UI at /docs
• ReDoc at /redoc
• Detailed error messages

Resources

• System Architecture
• Database Schema
• Agent Workflow
• API Reference
• FastAPI Docs
• LangGraph Docs
• Next.js Docs
• shadcn/ui Docs

Last updated: 2026-02-19