tCell

tCell is Antigen’s pre-built offensive security agent. The Antigen team continuously experiments, tests, and improves how tCell investigates systems, identifies weaknesses, and verifies vulnerabilities. Antigen builds tCell with the same Antigen SDK available to your team. Using tCell gives you those improvements without having to assemble and maintain an agent yourself.

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Access applications during testing

tCell uses Antigen’s identity infrastructure to interact with applications that require an account. It can sign up for services, sign in with Google accounts, and complete CAPTCHA challenges. These capabilities let tCell investigate application behavior beyond publicly accessible pages, including signup, login, and features available to signed-in users.

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What comes with tCell

tCell combines cyber-capable models with skills and guardrails configured by the Antigen team:

• Skills provide instructions that guide how the agent investigates.
• Guardrails constrain what the agent is allowed to do during a run.

These are already configured, so you can use tCell without assembling an agent yourself. During a run, tCell can query your Asset Map to understand the infrastructure behind a target and investigate relationships between services, resources, and identities.

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Run tCell

Your Antigen expert can plan an engagement and run tCell for your team. To discuss testing scope or plan an engagement, book office hours from the platform sidebar or schedule directly. You can also launch tCell through the SDK or API against approved targets. Confirmed vulnerabilities and their supporting evidence appear in the platform as tCell works. See Runs for how testing works and what happens to the results.

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Assemble your own agent

If you need a different combination of models, skills, or guardrails, you can assemble a custom agent with the Antigen SDK. Custom agents run in the same sandboxed environment as tCell and can access your organization’s Asset Map. See SDK → Agents for details.