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The browser extension is opfor’s no-code path. Install it, open any chat interface, click the icon, pick a suite, and watch it run. It’s built for everyone who doesn’t open a terminal — PMs, QA, designers, and security analysts. Everything runs client-side in your browser using your own LLM API keys. Nothing is sent to an opfor backend.
The extension covers agent / chatbot red-teaming. For MCP servers, use the CLI or MCP server.

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What it does

  • Auto-detects the chat widget on any page (custom UIs, Intercom, Zendesk, Drift, Salesforce, etc.)
  • Types attack prompts into the chat as if you were typing them, and watches the responses
  • Judges each response with an LLM and scores it pass / fail
  • Generates a self-contained HTML report you can download and share
It uses the same agent evaluator catalog as the CLI.

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Install

1

Add to your browser

Open the OPFOR listing on the Chrome Web Store and click Add to Chrome. Works in any Chromium browser (Chrome, Edge, Brave, Arc).
2

Pin the icon

Pin the OPFOR icon to your toolbar so it’s one click away on any page.
For contributors or testing unreleased changes:
git clone https://github.com/KeyValueSoftwareSystems/agent-opfor.git
cd agent-opfor
npm install
npm run build:catalog --workspace=@agent-opfor/extension
Then open chrome://extensions, enable Developer mode, click Load unpacked, and select the runners/extension/ folder.

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Configure your LLM

The extension uses a single LLM configuration for attack generation, judging, and HTML parsing. It’s stored in chrome.storage.local on your machine.
SettingDescription
ProviderOpenAI, Anthropic, Google, Groq, DeepSeek, Azure, or Custom (OpenAI-compatible)
ModelModel name — pick a common one or type your own
API KeyYour key for the selected provider
Use a capable model like GPT-4o or Claude Sonnet. Verdict quality depends on the model’s reasoning ability.
The gear icon exposes advanced settings: turns per attack (1–20, default 10), wait-after-send, message length limit, a manual agent description (fallback when auto-detect fails), a custom attack objective, business context, and an extra judge hint.

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Run a scan

1

Open the target

Open the chat interface you want to test in a browser tab.
2

Launch opfor

Click the OPFOR icon, then pick a Security Suite (e.g. OWASP LLM Top 10) or choose Custom Evaluators to select individual tests.
3

Set your LLM

Confirm provider, model, and API key, then click Execute.
4

Watch and download

The attacker types into the chat, the target replies, and live bubbles show the conversation. When it finishes, view the verdict and Download report.
The extension runs up to 20 turns per evaluator (default 10) and stops an evaluator early once the judge returns a definitive verdict.

What it tests

Same agent catalog as the CLI — full evaluator and suite reference.

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Limitations

  • Chat-widget targets only. It needs a detectable chat input + response area in the DOM. For standalone API endpoints or non-chat agents, use the CLI.
  • No MCP or live tool-call evaluators. The judge sees the transcript, not real tool side-effects. For MCP servers use the CLI’s mcp mode or the MCP server.
  • One agent per run — no inter-agent tests.
  • Vendor closed shadow-DOM widgets (Salesforce, some Intercom builds) may need a vendor-specific fallback. Open an issue with a sample URL if auto-detect fails.
  • No pause / resume across sessions — run state lives in chrome.storage.local; uninstalling wipes it.

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Privacy

  • API keys live in chrome.storage.local and never leave your browser. There is no opfor-hosted backend.
  • Attack prompts and target responses go only to the LLM providers you configure — the same data path as running the CLI on your own machine.
  • The extension does not phone home.