GPT‑6 Cyber vs. Claude Haiku 5.5

GPT-6 Cyber is a frontier AI cybersecurity model developed by OpenAI to support autonomous vulnerability research, exploit validation, secure software development, and advanced security testing. The model is specifically trained to investigate complex software environments, discover exploitable vulnerabilities, and help security professionals develop effective remediation strategies. Its capabilities include source code analysis, reverse engineering, vulnerability reproduction, exploit development, and investigation of security weaknesses across large software projects. GPT-6 Cyber can conduct extended security research workflows that involve identifying potential attack paths, testing hypotheses, validating technical findings, and producing reproducible evidence for security teams. During OpenAI's research campaigns, the model identified 81 previously unknown high-severity Firefox vulnerabilities and helped develop candidate patches for affected components. It also reproduced 1,724 Linux kernel vulnerabilities and generated working exploits for 948 of them, demonstrating its ability to validate security issues at scale. On the ExploitGym benchmark, GPT-6 Cyber achieved a 48.5% success rate compared with 32.1% for GPT-5.6 Cyber, while achieving 40.3% vulnerability recall in an internal web penetration testing evaluation. The model incorporates specialized alignment training to follow authorized testing scopes, respect security restrictions, and avoid exploiting systems that fall outside the researcher's stated objectives. In OpenAI's ExploitGym Honeypot evaluation, GPT-6 Cyber avoided attacking out-of-scope services in 99.93% of tests without deployment safety instructions and 100% of tests when those instructions were included. Its deployment safeguards include misalignment monitoring, misuse detection, IP allowlisting for API access, human oversight recommendations, and additional protections for operational technology and critical infrastructure systems.

Claude Haiku 5.5 is an Anthropic AI model built for high-volume and latency-sensitive AI workloads that require a balance of speed, cost, context capacity, and reasoning. Its primary use cases include classification, routing, information extraction, and subagent tasks within larger AI systems. Claude Haiku 5.5 introduces adaptive thinking, which allows the model to decide when reasoning is needed and how much thinking to apply before producing a response. Adaptive thinking is enabled by default, while the effort parameter gives developers a way to trade response quality against latency and cost. Developers can disable thinking at high effort or below, but Anthropic recommends using effort as the primary mechanism for controlling the model's reasoning behavior. The model provides a 1 million token context window, representing a substantial increase from the 200,000-token context window available with Claude Haiku 4.5. It can generate as many as 128,000 output tokens compared with the previous model's 64,000-token maximum, although thinking tokens are included within the configured output allowance. Browser use is available through the Claude API and Google Cloud, enabling developers to incorporate the model into workflows that require interaction with browser-based environments. Claude Haiku 5.5 uses the newer tokenizer found in Claude 4.7 and later models, resulting in approximately 30% more tokens for the same text compared with Claude Haiku 4.5, depending on the content. The model also changes several API behaviors, including replacing manual extended thinking with adaptive thinking, rejecting non-default sampling parameters and assistant-message prefills, and requiring updated computer-use tooling for supported environments.