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Welcome to ContextFort

ContextFort provides visibility and controls for browser agents like Claude, allowing you to monitor AI agent sessions, capture screenshots of agent actions, and enforce security policies to prevent unauthorized behavior.
Local-First Security: All data is stored locally on your machine. No screenshots or session data are transmitted to external servers.

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What is ContextFort?

ContextFort is a Chrome extension that tracks AI browser agent activity in real-time. When agents like Claude operate in your browser, ContextFort:
  • Captures screenshots of every click, input, and navigation
  • Tracks session data including URLs visited and actions taken
  • Enforces security policies to block unauthorized agent actions
  • Prevents context mixing between sensitive domains
  • Manages session isolation with separate human and agent login profiles

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Key Features

Real-Time Monitoring

Automatic screenshot capture of all agent interactions - clicks, inputs, and page navigations with detailed event metadata.

Session Isolation

Separate agent and human browser sessions with automatic cookie swapping to protect your personal accounts.

Security Controls

Block agent access to specific domains, URLs, or page elements. Prevent context mixing between sensitive websites.

Local Storage Only

All screenshots and session data stored locally with Chrome’s built-in encryption. No external transmission.

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How It Works

1

Install Extension

Add ContextFort to Chrome from the Chrome Web Store. No developer mode required.
2

Enable Agent Mode

When Claude or another agent starts operating, ContextFort detects the agent tab and begins monitoring automatically. The tab group shows a ⌛ emoji indicator.
3

View Dashboard

Access the ContextFort dashboard by clicking the extension icon. View live screenshots, session history, and agent activity.
4

Configure Controls

Set up security policies in the Controls section - block domains, prevent context mixing, or restrict specific actions.

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Use Cases

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Security Teams

  • Monitor AI agent behavior across the organization
  • Enforce policies preventing access to sensitive internal tools
  • Audit trail for compliance and incident investigation

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Individual Users

  • Verify agents aren’t accessing unintended websites
  • Keep agent sessions separate from personal accounts
  • Review agent actions to understand behavior

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Developers

  • Debug agent workflows with visual step-by-step records
  • Test agent boundaries and security policies
  • Analyze agent decision-making patterns

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Architecture

ContextFort operates entirely within your browser:
  • Content Script: Injected into web pages to detect agent activity
  • Background Worker: Captures screenshots and enforces blocking rules (chrome-extension/background.js:1-1414)
  • Chrome Storage: Local encrypted storage for sessions and screenshots
  • Dashboard: Visual interface for reviewing agent activity
ContextFort requires Chrome version 134 or higher due to modern extension API requirements.

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Security & Privacy

No External Servers

All data processing happens locally. ContextFort has no backend infrastructure.

Encrypted at Rest

Chrome encrypts extension storage using OS-level encryption. Your data is secure.

No PII Transmission

Screenshots may contain sensitive information, but they never leave your device.

Open Source

Full source code available on GitHub for security audits.

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Optional Analytics

ContextFort includes optional PostHog analytics for usage events (agent start/stop, rule changes). To disable:
  1. Locate background.js line 2
  2. Change const ENABLE_POSTHOG = true; to false
  3. No PII or screenshots are ever sent to analytics
See DATA_POLICY.md for complete details.

Quickstart

Get started in 5 minutes

Installation

Detailed install instructions

Chrome Web Store

Install now

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Enterprise Readiness

ContextFort is on the path to enterprise compliance:
  • 🔄 SOC2 Type 2 compliance (Q2 2025)
  • 🔄 ISO 27001 certification (Q3 2025)
  • 🔄 GDPR compliance documentation (Q2 2025)
  • 🔄 Centralized dashboard for enterprise deployment (Q3 2025)
See COMPLIANCE.md for the roadmap.

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Support

Need help?
For security vulnerabilities, do not open public issues. Use Private Vulnerability Reporting or email [email protected].

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Next Steps

Ready to get started?

Start with Quickstart

Follow our 5-minute guide to install ContextFort and monitor your first agent session.

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