Google is introducing a new approach to cybersecurity, focusing on artificial intelligence as the first line of digital defence. The company has introduced Big Sleep, an AI agent developed by Google DeepMind in collaboration with Project Zero, which has successfully stopped a security threat before it was launched. The tool is also being used to strengthen the security of open-source software, increasing defensive coverage. Google’s secure-by-design approach emphasizes human oversight, transparency, and privacy. In addition to Big Sleep, Google is infusing AI into its security infrastructure: Timesketch, the company’s open-source forensics platform, now integrates Sec-Gemini-powered agents to automate incident response. FACADE, an insider threat detection tool, processes billions of security events each day using contrastive learning, without relying on historical attack data. A new AI-assisted Capture the Flag challenge at DEF CON 33 will give participants hands-on experience working alongside AI agents in real-time cyber defence scenarios.