Environment Variables

Complete reference for all environment variables in Nectr AI PR Review Agent

Nectr uses environment variables for all configuration. Copy .env.example to .env and configure the required variables to get started.

Required Variables

These variables must be set for Nectr to start and review PRs.

AI Configuration

ANTHROPIC_API_KEY · string · required

Your Anthropic API key for Claude Sonnet 4.5.

Get your API key from console.anthropic.com

ANTHROPIC_API_KEY=sk-ant-...

ANTHROPIC_MODEL · string · default: "claude-sonnet-4-5-20250929"

The Claude model to use for PR reviews.

ANTHROPIC_MODEL=claude-sonnet-4-5-20250929

Database

DATABASE_URL · string · required

PostgreSQL connection string with asyncpg driver.

Recommended: Use Supabase free tier.

Navigate to: Dashboard → Connect → Connection Pooling → Session Mode (port 5432)

DATABASE_URL=postgresql+asyncpg://postgres.<project-id>:<password>@aws-0-<region>.pooler.supabase.com:5432/postgres

Use postgresql+asyncpg:// (not postgresql://) as Nectr requires async database support.

GitHub OAuth

GITHUB_CLIENT_ID · string · required

GitHub OAuth App client ID.

Create an OAuth App at: github.com/settings/developers → New OAuth App

GITHUB_CLIENT_ID=Iv1.abc123...

GITHUB_CLIENT_SECRET · string · required

GitHub OAuth App client secret.

GITHUB_CLIENT_SECRET=abc123def456...

Keep this secret secure. Never commit it to version control.

GITHUB_PAT · string · required

GitHub Personal Access Token (Classic) with repo scope.

Used to post PR review comments on behalf of your account.

Create at: github.com/settings/tokens → Generate new token (classic)

Required scope: repo (Full control of private repositories)

GITHUB_PAT=ghp_...

Authentication

SECRET_KEY · string · required

Secret key for JWT signing and token encryption.

Generate a secure random key:

python -c "import secrets; print(secrets.token_hex(32))"

SECRET_KEY=your-64-character-hex-string

Changing this key will invalidate all existing user sessions and require users to re-authenticate.

ALGORITHM · string · default: "HS256"

JWT signing algorithm.

ALGORITHM=HS256

ACCESS_TOKEN_EXPIRE_MINUTES · integer · default: "1440"

JWT token expiration time in minutes (default: 24 hours).

ACCESS_TOKEN_EXPIRE_MINUTES=1440

URLs

BACKEND_URL · string · required

Public URL where your backend API is hosted.

This URL is used for:

• GitHub webhook callback endpoints
• OAuth redirect URIs

# Development
BACKEND_URL=http://localhost:8000

# Production
BACKEND_URL=https://your-backend.up.railway.app

FRONTEND_URL · string · required

Public URL where your frontend is hosted.

Used for redirects after authentication.

# Development
FRONTEND_URL=http://localhost:3000

# Production
FRONTEND_URL=https://your-app.vercel.app

Neo4j Knowledge Graph

NEO4J_URI · string · required

Neo4j connection URI.

Enables file-expert maps and related-PR context in every review.

Get a free instance at: neo4j.com/cloud/platform/aura-graph-database

NEO4J_URI=neo4j+s://xxxxxxxx.databases.neo4j.io

NEO4J_USERNAME · string · default: "neo4j"

Neo4j username.

NEO4J_USERNAME=neo4j

NEO4J_PASSWORD · string · required

Neo4j password.

NEO4J_PASSWORD=your-neo4j-password

Mem0 Memory Layer

MEM0_API_KEY · string · required

Mem0 API key for semantic memory storage.

Enables per-project patterns and per-developer learned habits.

Get your API key at: mem0.ai

MEM0_API_KEY=m0-...

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Optional Variables

These variables enable optional features. Leave blank to disable.

MCP Integrations

Pull live context (issues, errors, messages) into every review. Each integration is independent — set only the ones you use.

Linear Integration

LINEAR_MCP_URL · string

Linear MCP server base URL.

LINEAR_MCP_URL=https://your-linear-mcp-server.com

LINEAR_API_KEY · string

Linear personal API key.

Get your API key from: Linear → Settings → API → Personal API keys

LINEAR_API_KEY=lin_api_...

Sentry Integration

SENTRY_MCP_URL · string

Sentry MCP server base URL.

SENTRY_MCP_URL=https://your-sentry-mcp-server.com

SENTRY_AUTH_TOKEN · string

Sentry auth token with project read permissions.

Create at: Sentry → Settings → Auth Tokens

SENTRY_AUTH_TOKEN=sntrys_...

Slack Integration

SLACK_MCP_URL · string

Slack MCP server base URL for fetching relevant channel messages.

SLACK_MCP_URL=https://your-slack-mcp-server.com

Slack Bot (Direct Notifications)

SLACK_BOT_TOKEN · string

Slack Bot User OAuth Token for direct notifications.

This is separate from the MCP Slack integration above.

SLACK_BOT_TOKEN=xoxb-...

SLACK_SIGNING_SECRET · string

Slack app signing secret for verifying webhook requests.

SLACK_SIGNING_SECRET=abc123...

Webhook Security

GITHUB_WEBHOOK_SECRET · string

Global fallback webhook secret.

Per-repo secrets are stored in the database automatically when you connect a repo. This global secret is only used as a fallback if no per-repo secret is found.

GITHUB_WEBHOOK_SECRET=your-webhook-secret

In production (APP_ENV=production), webhook signature verification is enforced. Without a valid secret, webhooks will be rejected with a 403 error.

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Feature Flags

PARALLEL_REVIEW_AGENTS · boolean · default: "false"

Enable parallel review mode with 3 specialized agents.

• false (default): Single agentic review loop (faster, less token usage)
• true: 3 specialized agents run in parallel (security / performance / style)

PARALLEL_REVIEW_AGENTS=false

How Parallel Agents Work

When enabled, Nectr runs three specialized agents concurrently:

1. Security Agent - Focuses on vulnerabilities, authentication, data validation
2. Performance Agent - Analyzes efficiency, database queries, caching
3. Style Agent - Reviews code style, patterns, and maintainability

A synthesis agent then combines all three reviews into a final cohesive review.

Trade-offs:

• ✅ More thorough, specialized analysis
• ✅ Parallel execution can be faster for large PRs
• ❌ Higher token usage (4x Claude API calls)
• ❌ Slightly higher cost per review

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App Settings

Safe to leave as-is for local development.

APP_NAME · string · default: "Nectr"

Application name.

APP_NAME=Nectr

APP_ENV · string · default: "development"

Application environment.

• development - Development mode (CORS relaxed, debug enabled)
• production - Production mode (CORS strict, webhook signature verification enforced)

APP_ENV=development

DEBUG · boolean · default: "true"

Enable debug mode.

DEBUG=True

LOG_LEVEL · string · default: "DEBUG"

Logging level.

Options: DEBUG, INFO, WARNING, ERROR, CRITICAL

LOG_LEVEL=DEBUG

HOST · string · default: "0.0.0.0"

Server host binding.

HOST=0.0.0.0

PORT · integer · default: "8000"

Server port.

PORT=8000

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Example Configuration

Minimal Configuration (Required Only)

# AI
ANTHROPIC_API_KEY=sk-ant-api03-xxx
ANTHROPIC_MODEL=claude-sonnet-4-5-20250929

# Database
DATABASE_URL=postgresql+asyncpg://postgres.abc:[e-mail]:5432/postgres

# GitHub OAuth
GITHUB_CLIENT_ID=Iv1.abc123
GITHUB_CLIENT_SECRET=secret123
GITHUB_PAT=ghp_abc123

# Auth
SECRET_KEY=64-character-random-hex-string

# URLs
BACKEND_URL=http://localhost:8000
FRONTEND_URL=http://localhost:3000

# Neo4j
NEO4J_URI=neo4j+s://abc123.databases.neo4j.io
NEO4J_USERNAME=neo4j
NEO4J_PASSWORD=password

# Mem0
MEM0_API_KEY=m0-abc123

Full Configuration (All Features)

# ══════════════════════════════════════════════════════
# REQUIRED
# ══════════════════════════════════════════════════════

# AI
ANTHROPIC_API_KEY=sk-ant-api03-xxx
ANTHROPIC_MODEL=claude-sonnet-4-5-20250929

# Database
DATABASE_URL=postgresql+asyncpg://postgres.abc:[e-mail]:5432/postgres

# GitHub OAuth + API
GITHUB_CLIENT_ID=Iv1.abc123
GITHUB_CLIENT_SECRET=secret123
GITHUB_PAT=ghp_abc123

# Auth
SECRET_KEY=64-character-random-hex-string
ACCESS_TOKEN_EXPIRE_MINUTES=1440
ALGORITHM=HS256

# URLs
BACKEND_URL=https://your-backend.up.railway.app
FRONTEND_URL=https://your-app.vercel.app

# Neo4j
NEO4J_URI=neo4j+s://abc123.databases.neo4j.io
NEO4J_USERNAME=neo4j
NEO4J_PASSWORD=password

# Mem0
MEM0_API_KEY=m0-abc123

# ══════════════════════════════════════════════════════
# OPTIONAL
# ══════════════════════════════════════════════════════

# MCP Integrations
LINEAR_MCP_URL=https://linear-mcp.example.com
LINEAR_API_KEY=lin_api_abc123
SENTRY_MCP_URL=https://sentry-mcp.example.com
SENTRY_AUTH_TOKEN=sntrys_abc123
SLACK_MCP_URL=https://slack-mcp.example.com

# Slack Bot (Direct Notifications)
SLACK_BOT_TOKEN=xoxb-abc123
SLACK_SIGNING_SECRET=abc123

# Webhook Security
GITHUB_WEBHOOK_SECRET=webhook-secret-123

# Feature Flags
PARALLEL_REVIEW_AGENTS=false

# App Settings
APP_NAME=Nectr
APP_ENV=production
DEBUG=False
LOG_LEVEL=INFO
HOST=0.0.0.0
PORT=8000

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Next Steps

OAuth Setup

Configure GitHub OAuth App for user authentication

Webhooks

Learn how webhooks are configured and verified