Security & Privacy

Your code stays on your machine—Arc0 only streams agent conversations and diffs, never your full codebase.

Architecture Overview

┌─────────────────────────────────────────────────────────┐
│                  Your Machine (Private)                  │
│                                                         │
│  ┌──────────┐    ┌──────────────┐    ┌──────────────┐ │
│  │ Codebase │    │   Arc0 CLI   │    │ Coding Agent │ │
│  │          │    │              │    │              │ │
│  │ (stays   │───▶│  (filters &  │◀──▶│ (runs here)  │ │
│  │  here)   │    │   streams)   │    │              │ │
│  └──────────┘    └──────┬───────┘    └──────────────┘ │
│                         │                              │
└─────────────────────────┼──────────────────────────────┘
                          │
                   WSS Tunnel (encrypted)
                    (diffs, prompts,
                     NOT full code)
                          │
                          ▼
                  ┌──────────────┐
                  │ Your Phone   │
                  │ (Arc0 App)   │
                  └──────────────┘

What Gets Sent

Arc0 CLI only streams to your phone:

Example

If your agent modifies src/auth.ts, Arc0 sends:

• The diff (changes only)
• The filename
• The agent's question about the change

Arc0 does NOT send:

• The full file contents
• Other files in your project
• Your .env file
• Git credentials

Data in Transit

All data between Arc0 CLI and the mobile app is encrypted:

• WSS (WebSocket Secure) for all connections
• End-to-end encryption for message content
• Perfect forward secrecy for session keys

Tunnel Connection

Arc0 uses a secure tunnel for connectivity:

• Traffic is encrypted end-to-end via WSS
• Works behind NAT, firewalls, corporate networks
• Low latency for real-time communication
• Relay servers only see encrypted blobs—we cannot read your data

Data at Rest

On Your Machine

Arc0 CLI stores minimal data locally:

• Configuration file (~/.arc0/config.yaml)
• Session logs (configurable retention)
• Pairing credentials (encrypted)

# Configure data retention
storage:
  session_retention: 7d # Delete after 7 days
  log_retention: 30d
  encrypt_logs: true

On Your Phone

The Arc0 app stores:

• Pairing credentials (encrypted, in device keychain)
• Session cache (configurable)
• App preferences

Data is encrypted using device encryption (iOS Keychain, Android Keystore).

Clearing Data

Clear all local data:

# On your machine
arc0 clear-data

# On your phone
Settings → Arc0 → Clear Data

Authentication

Device Pairing

Devices are paired using QR codes that contain:

• A one-time pairing token
• CLI's public key
• Connection information

The QR code is valid for 5 minutes and single-use.

Session Authentication

After pairing:

• Devices authenticate using stored credentials
• Sessions are validated with signed tokens
• Invalid sessions are rejected

Revoking Access

Unpair a device:

# List paired devices
arc0 devices

# Remove a device
arc0 unpair <device-id>

Or from the app: Settings → Devices → Remove

Open Source

Arc0 CLI is fully open source:

• Repository: github.com/amicalhq/arc0
• License: MIT
• Security audits: Welcomed

You can:

• Audit the code yourself
• Build from source
• Self-host entirely
• Contribute security improvements

No Server Dependency

Arc0 works without our servers:

• CLI runs locally on your machine
• Mobile app connects directly via tunnel
• No account required
• No telemetry by default

Optional Telemetry

If enabled, we collect:

• App version
• Error reports (opt-in)
• Feature usage (anonymized)

Never:

• Your code
• Your prompts
• Your responses

Disable telemetry:

telemetry:
  enabled: false

Best Practices

Development Machine

• Keep Arc0 CLI updated for security patches
• Use strong device passwords
• Enable disk encryption
• Review paired devices regularly

Mobile App

• Enable device lock (PIN, biometric)
• Use app lock feature (Settings → Security)
• Don't share QR codes
• Unpair lost devices immediately

Network

• Use trusted networks when possible
• Enable TLS for remote connections
• Consider VPN for sensitive work
• Firewall the CLI port when not in use

Compliance

Arc0's architecture supports compliance requirements:

Threat Model

What Arc0 Protects Against

• Network eavesdropping (encryption)
• Unauthorized device access (pairing)
• Data leakage (minimal data streaming)
• Session hijacking (signed tokens)

What Arc0 Doesn't Protect Against

• Compromised development machine
• Physical access to your devices
• Malicious CLI modifications (verify source)
• Agent vulnerabilities (separate concern)

Next Steps