LexGuard

Adversarial Multi-Agent AI for Contract Intelligence

LexGuard is an AI-powered contract analysis platform that uses three adversarial Gemini 2.5 Flash agents working in sequence to detect exploitative clauses, verify findings, and simulate worst-case consequences. Unlike single-prompt summarizers, LexGuard's adversarial design — two agents arguing about the same document — catches edge cases a single pass would miss.

Screenshot: Hero / Landing Page

Features

3-Agent Adversarial Pipeline — Detective hunts risky clauses, Judge verifies and scores them, Simulator generates worst-case narratives
Multi-Format Upload — Drag-and-drop PDF, DOCX, or paste raw text (up to 20K characters)
Risk Scoring — Quantified 0-100 risk score with severity breakdown (Critical / High / Medium / Low)
Clause Highlighting — Predatory clauses marked directly on the contract text with color-coded severity
Worst-Case Simulator — On-demand second-person consequence stories for high-risk clauses
OAuth + Credentials Auth — Sign in with Google, GitHub, or email/password via NextAuth v5
User Profiles — Avatar upload, editable name, plan management, password change
Contract Management — Grid/list views, search, sort, filter by risk level
Data Export — Download all analyses as JSON
Plans & Pricing — Free tier (10 analyses/day) and Pro tier ($5/month, unlimited)
Responsive Design — Neo-brutalist UI with Tailwind CSS v4, print-ready reports

Screenshots

Dashboard — Recent analyses, risk overview, quick stats

Upload — Drag-and-drop PDF/DOCX or paste contract text

Analysis Detail — Two-pane risk workbench with clause highlighting

Contracts — Grid/list view, search, filter by risk level

Worst-Case Simulator — AI-generated consequence narratives

Profile — Avatar, plan, auth provider, password management

Plans & Pricing — Free vs Pro tier comparison

Sign In — OAuth (Google, GitHub) + credentials

System Architecture

System Design Diagram

Mermaid source (click to expand)

flowchart TD
    A["User Browser"] -->|"Upload PDF/DOCX or paste text"| FE

    subgraph FE["Next.js 16 Frontend"]
        B["Upload Screen"]
        C["API Proxy: /api/parse"]
        D["API Proxy: /api/analyze"]
        E["API Proxy: /api/simulate"]
        R["Dashboard + Analysis Detail"]
        AUTH["NextAuth v5<br/>Google · GitHub · Credentials"]
    end

    subgraph BE["Python FastAPI Backend"]
        P["POST /parse<br/>pdfplumber · python-docx"]
        AN["POST /analyze"]
        SIM["POST /simulate"]
        DET["Agent 1: Detective<br/>Adversarial Clause Hunter"]
        JUD["Agent 2: Judge<br/>Verifier + Risk Scorer"]
        SCN["Agent 3: Simulator<br/>Consequence Narrator"]
    end

    B -->|"file upload"| C -->|"FormData proxy"| P
    P -->|"raw text"| B
    B -->|"contract text"| D -->|"contract_text"| AN
    AN --> DET -->|"raw findings JSON"| JUD
    JUD -->|"ContractAnalysis JSON"| R
    R -->|"critical findings"| E -->|"findings + summary"| SIM
    SIM --> SCN -->|"SimulationResult JSON"| R

    DET & JUD & SCN -->|"gemini-2.5-flash"| GEMINI[("Google Gemini API")]
    FE -->|"Auth + Data"| SUPA[("Supabase PostgreSQL")]
    AUTH -->|"JWT sessions"| FE

Agent Pipeline

Agent	File	Role	Temp	Output
Detective	`backend/detective.py`	Scans for every clause that could harm the signer. Classifies into 13 risk categories.	0.1	Raw `Finding[]`
Judge	`backend/judge.py`	Independently verifies each finding against the source. Confirms, upgrades, downgrades, or dismisses. Computes risk score.	0.1	Full `ContractAnalysis`
Simulator	`backend/simulate.py`	Generates vivid worst-case consequence stories for critical/high findings.	0.7	`SimulationResult`

Risk Scoring Formula

overall_risk_score = min(CRITICAL x 25 + HIGH x 10 + MEDIUM x 5 + LOW x 1, 100)

Score	Level
0 - 19	SAFE
20 - 39	LOW
40 - 59	MEDIUM
60 - 79	HIGH
80 - 100	CRITICAL

Tech Stack

Layer	Technology	Purpose
Frontend	Next.js 16 + React 19	App Router, SSR, API proxies
Styling	Tailwind CSS v4	Utility-first CSS, neo-brutalist design system
Auth	NextAuth v5	Google, GitHub, Credentials providers (JWT sessions)
Icons	Lucide React	UI icon set
File Upload	react-dropzone	Drag-and-drop interface
Backend	FastAPI	REST API, agent orchestration
AI	Gemini 2.5 Flash	All three agents via `google-genai` SDK
Database	Supabase (PostgreSQL)	Users, documents, analyses, findings, simulations
Deployment	Google Cloud Run	Single-container Docker (Node 22 + Python 3.11)

Getting Started

Prerequisites

Node.js >= 22
Python >= 3.11
npm (comes with Node.js)
A Google Gemini API key (Get one here)
A Supabase project (Create one here)

1. Clone the repository

git clone https://github.com/your-username/lexguard.git
cd lexguard

2. Install frontend dependencies

npm install

3. Install backend dependencies

cd backend
pip install -r requirements.txt
cd ..

4. Set up environment variables

Create a .env.local file in the project root:

cp .env.example .env.local
# Edit .env.local with your actual keys (see Environment Variables section)

5. Start the development servers

Terminal 1 — Backend:

cd backend
uvicorn main:app --host 0.0.0.0 --port 8000 --reload

Terminal 2 — Frontend:

npm run dev

Open http://localhost:3001 in your browser.

Environment Variables

Create a .env.local file with the following:

# Google Gemini
GEMINI_API_KEY=your_gemini_api_key

# Python backend URL
BACKEND_URL=http://localhost:8000

# NextAuth.js
NEXTAUTH_URL=http://localhost:3001
NEXTAUTH_SECRET=generate-with-openssl-rand-base64-32

# Google OAuth
GOOGLE_CLIENT_ID=your_google_client_id
GOOGLE_CLIENT_SECRET=your_google_client_secret

# GitHub OAuth
GITHUB_CLIENT_ID=your_github_client_id
GITHUB_CLIENT_SECRET=your_github_client_secret

# Supabase
NEXT_PUBLIC_SUPABASE_URL=https://your-project.supabase.co
NEXT_PUBLIC_SUPABASE_ANON_KEY=your_anon_key
SUPABASE_SERVICE_ROLE_KEY=your_service_role_key

Project Structure

lexguard/
├── app/
│   ├── (marketing)/
│   │   └── page.tsx                  # Landing page
│   ├── (app)/
│   │   ├── layout.tsx                # Authenticated layout with sidebar
│   │   ├── dashboard/page.tsx        # Dashboard — recent analyses, stats
│   │   ├── upload/page.tsx           # Contract upload screen
│   │   ├── contracts/page.tsx        # Contract list — grid/list, search, filter
│   │   ├── analysis/[id]/page.tsx    # Analysis detail — two-pane risk workbench
│   │   ├── profile/page.tsx          # User profile — avatar, plan, password
│   │   ├── settings/page.tsx         # Settings — theme, export, delete account
│   │   └── plans/page.tsx            # Plans & pricing
│   ├── auth/
│   │   ├── signin/page.tsx           # Sign in (OAuth + credentials)
│   │   └── signup/page.tsx           # Sign up (email + password)
│   ├── api/
│   │   ├── analyze/route.ts          # Proxy → backend /analyze + persist to DB
│   │   ├── parse/route.ts            # Proxy → backend /parse
│   │   ├── simulate/route.ts         # Proxy → backend /simulate
│   │   ├── analyses/
│   │   │   ├── route.ts              # GET all user analyses
│   │   │   └── [id]/route.ts         # GET/DELETE single analysis
│   │   ├── auth/signup/route.ts      # Credentials signup
│   │   └── user/
│   │       ├── profile/route.ts      # GET/PATCH/DELETE user profile
│   │       ├── password/route.ts     # PATCH password
│   │       └── export/route.ts       # GET data export (JSON)
│   ├── globals.css                   # Design system + Tailwind imports
│   └── layout.tsx                    # Root layout
├── components/
│   ├── ContractUpload.tsx            # Drag-drop + paste textarea
│   ├── FindingCard.tsx               # Clause card (severity, verdict, tips)
│   ├── FindingsList.tsx              # Filtered + sorted findings
│   ├── RiskScoreBadge.tsx            # SVG circular risk meter (0-100)
│   ├── SimulatePanel.tsx             # Worst-case scenario panel
│   ├── SummaryStats.tsx              # Severity count breakdown
│   └── layout/
│       ├── Sidebar.tsx               # Navigation sidebar
│       └── UserMenu.tsx              # User dropdown menu
├── lib/
│   ├── auth.ts                       # NextAuth v5 config + JWT callbacks
│   ├── constants.ts                  # Route constants
│   └── supabase/
│       └── server.ts                 # Supabase server client
├── types/
│   └── analysis.ts                   # Shared TypeScript interfaces
├── backend/
│   ├── main.py                       # FastAPI app, CORS, endpoints
│   ├── parser.py                     # PDF + DOCX + plaintext extraction
│   ├── detective.py                  # Agent 1: clause hunter
│   ├── judge.py                      # Agent 2: verifier + scorer
│   ├── simulate.py                   # Agent 3: consequence narrator
│   ├── gemini_client.py              # Gemini API client wrapper
│   └── requirements.txt              # Python dependencies
├── middleware.ts                      # Route protection (auth redirects)
├── Dockerfile                        # Multi-stage build (Node 22 + Python 3.11)
├── start.sh                          # Container entrypoint (backend + frontend)
├── next.config.ts                    # Next.js config (standalone output, 20MB body limit)
└── ARCHITECTURE.md                   # Detailed architecture document

Database Schema

Entity-Relationship Diagram

Table `organizations`

Columns

Name	Type	Constraints
`id`	`uuid`	Primary
`name`	`text`
`domain`	`text`	Nullable Unique
`plan`	`text`
`settings`	`jsonb`	Nullable
`created_at`	`timestamptz`
`updated_at`	`timestamptz`

Table `users`

Columns

Name	Type	Constraints
`id`	`uuid`	Primary
`email`	`text`	Unique
`name`	`text`	Nullable
`avatar_url`	`text`	Nullable
`auth_provider`	`text`
`plan`	`text`
`org_id`	`uuid`	Nullable
`analyses_this_month`	`int4`
`created_at`	`timestamptz`
`updated_at`	`timestamptz`
`password_hash`	`text`	Nullable
`ls_customer_id`	`text`	Nullable

Table `documents`

Columns

Name	Type	Constraints
`id`	`uuid`	Primary
`user_id`	`uuid`
`file_name`	`text`
`file_type`	`text`	Nullable
`detected_type`	`text`	Nullable
`contract_text`	`text`	Nullable
`char_count`	`int4`
`storage_path`	`text`	Nullable
`created_at`	`timestamptz`

Table `analyses`

Columns

Name	Type	Constraints
`id`	`uuid`	Primary
`document_id`	`uuid`
`user_id`	`uuid`
`risk_score`	`int4`
`risk_level`	`text`
`judge_confidence`	`float8`	Nullable
`contract_summary`	`text`	Nullable
`total_findings`	`int4`
`critical_count`	`int4`
`high_count`	`int4`
`medium_count`	`int4`
`low_count`	`int4`
`false_positives_removed`	`int4`
`analyzed_at`	`timestamptz`

Table `findings`

Columns

Name	Type	Constraints
`id`	`uuid`	Primary
`analysis_id`	`uuid`
`finding_ref`	`text`
`title`	`text`
`category`	`text`
`severity`	`text`
`clause_text`	`text`	Nullable
`clause_location`	`text`	Nullable
`detective_finding`	`text`	Nullable
`judge_verdict`	`text`	Nullable
`plain_english_impact`	`text`	Nullable
`recommendation`	`text`	Nullable
`negotiation_tip`	`text`	Nullable
`verified`	`bool`
`false_positive`	`bool`
`sort_order`	`int4`

Table `simulations`

Columns

Name	Type	Constraints
`id`	`uuid`	Primary
`analysis_id`	`uuid`
`worst_case_story`	`text`	Nullable
`financial_risk`	`text`	Nullable
`time_risk`	`text`	Nullable
`probability`	`text`	Nullable
`scenarios`	`jsonb`	Nullable
`created_at`	`timestamptz`

Table `policies`

Columns

Name	Type	Constraints
`id`	`uuid`	Primary
`org_id`	`uuid`
`name`	`text`
`allowed_doc_types`	`_text`	Nullable
`max_risk_threshold`	`int4`	Nullable
`auto_reject_critical`	`bool`
`require_simulation`	`bool`
`monthly_analysis_limit`	`int4`	Nullable
`is_active`	`bool`
`created_at`	`timestamptz`
`updated_at`	`timestamptz`

API Reference

FastAPI Backend

Method	Endpoint	Description
`GET`	`/health`	Health check
`POST`	`/parse`	Extract text from PDF/DOCX (`multipart/form-data`)
`POST`	`/analyze`	Run Detective + Judge pipeline (`{ contract_text }`)
`POST`	`/simulate`	Run Simulator on findings (`{ findings, contract_summary }`)

Next.js API Routes

Method	Endpoint	Description
`POST`	`/api/parse`	Proxy to backend `/parse`
`POST`	`/api/analyze`	Proxy to backend `/analyze` + persist to Supabase
`POST`	`/api/simulate`	Proxy to backend `/simulate`
`GET`	`/api/analyses`	List all analyses for authenticated user
`GET`	`/api/analyses/:id`	Get single analysis with findings
`DELETE`	`/api/analyses/:id`	Delete analysis and associated data
`POST`	`/api/auth/signup`	Register with email + password
`GET`	`/api/user/profile`	Get user profile
`PATCH`	`/api/user/profile`	Update name / avatar
`DELETE`	`/api/user/profile`	Delete account + all data
`PATCH`	`/api/user/password`	Change password (credentials users)
`GET`	`/api/user/export`	Export all user data as JSON

Deployment

Google Cloud Run (Production)

LexGuard ships as a single Docker container running both the Next.js frontend and FastAPI backend, managed by a shell script entrypoint.

# Set your project
PROJECT_ID=$(gcloud config get-value project)

# Build and push the container
gcloud builds submit . --tag gcr.io/$PROJECT_ID/lexguard

# Deploy to Cloud Run
gcloud run deploy lexguard \
  --image gcr.io/$PROJECT_ID/lexguard \
  --platform managed \
  --region us-central1 \
  --allow-unauthenticated \
  --memory 1Gi \
  --cpu 2 \
  --timeout 120 \
  --set-env-vars "\
GEMINI_API_KEY=your_key,\
NEXTAUTH_URL=https://your-service-url.run.app,\
NEXTAUTH_SECRET=your_secret,\
GOOGLE_CLIENT_ID=your_id,\
GOOGLE_CLIENT_SECRET=your_secret,\
GITHUB_CLIENT_ID=your_id,\
GITHUB_CLIENT_SECRET=your_secret,\
NEXT_PUBLIC_SUPABASE_URL=https://your-project.supabase.co,\
NEXT_PUBLIC_SUPABASE_ANON_KEY=your_anon_key,\
SUPABASE_SERVICE_ROLE_KEY=your_service_role_key"

Alternative: Split Deployment

Component	Platform	Notes
Frontend	Vercel	Zero-config Next.js hosting. Set `BACKEND_URL` env var.
Backend	Render	Connect repo, set `GEMINI_API_KEY`. Auto-detects Dockerfile.

# Deploy frontend to Vercel
npm i -g vercel && vercel --prod

# Backend on Render: connect repo via dashboard
# Set env: GEMINI_API_KEY=your_key

Design System

LexGuard speaks one opinionated visual language — Retro Neo-Brutalism — applied consistently across every screen, badge, and report. The intent is a tactile, high-contrast interface where structure is always visible and nothing hides behind soft gradients or blur.

Core principles

Borders — Hard 2px solid ink borders on every container; zero border-radius (sharp corners only)
Shadows — Offset hard drop shadows on a 4px → 5px → 6px scale (e.g. 5px 5px 0px 0px #1a1a1a), never blurred
Typography — Space Grotesk (bold, uppercase) for headings, Space Mono for body copy and accents
Motion — Interactive elements translate along the shadow axis for a physical press-down feel, rather than fading
Dark mode — A full design-token swap: ink canvas, bright-chalk borders, and neon-shifted accent colors

Color palette

Color	Hex	Usage
Sand	`#f5f4f0`	Page backgrounds
Ink	`#1a1a1a`	Text, borders, shadows
Lilac	`#d2c4fb`	Active states, primary accent
Yellow	`#ffe082`	Pro tier, highlights, warnings
Coral	`#ff8a80`	Danger, critical severity
Mint	`#a7ffeb`	Success, safe severity

License

Released under the MIT License — see the LICENSE file for the full text.

MIT License

Copyright (c) 2026 Sumedh-6504

You are free to use, copy, modify, merge, publish, distribute, sublicense, and sell copies of the software, provided the copyright notice and permission notice are included in all copies or substantial portions.

Name		Name	Last commit message	Last commit date
Latest commit History 34 Commits
app		app
backend		backend
components		components
images		images
lib		lib
public		public
types		types
.dockerignore		.dockerignore
.gitignore		.gitignore
Dockerfile		Dockerfile
LICENSE		LICENSE
README.md		README.md
eslint.config.mjs		eslint.config.mjs
middleware.ts		middleware.ts
next.config.ts		next.config.ts
package-lock.json		package-lock.json
package.json		package.json
postcss.config.mjs		postcss.config.mjs
start.sh		start.sh
tsconfig.json		tsconfig.json

Folders and files

Latest commit

History

Repository files navigation

LexGuard

Table of Contents

Features

Screenshots

System Architecture

Agent Pipeline

Risk Scoring Formula

Tech Stack

Getting Started

Prerequisites

1. Clone the repository

2. Install frontend dependencies

3. Install backend dependencies

4. Set up environment variables

5. Start the development servers

Environment Variables

Project Structure

Database Schema

Table organizations

Columns

Table users

Columns

Table documents

Columns

Table analyses

Columns

Table findings

Columns

Table simulations

Columns

Table policies

Columns

API Reference

FastAPI Backend

Next.js API Routes

Deployment

Google Cloud Run (Production)

Alternative: Split Deployment

Design System

License

About

Topics

Resources

License

Uh oh!

Stars

Watchers

Forks

Releases 2

Contributors

Uh oh!

Languages

Table `organizations`

Table `users`

Table `documents`

Table `analyses`

Table `findings`

Table `simulations`

Table `policies`