Trusted access for the next era of cyber defense

Simon Willison’s Weblog Subscribe Sponsored by: Teleport — Connect agents to your infra in seconds with Teleport Beams. Built-in identity. Zero secrets. Get early access Trusted access for the next era of cyber defense (via) OpenAI's answer to Claude Mythos appears to be a new model called GPT-5.4-Cyber: In preparation for increasingly more capable models from OpenAI over the next few months, we are fine-tuning our models specifically to enable defensive cybersecurity use cases, starting today with a variant of GPT‑5.4 trained to be cyber-permissive: GPT‑5.4‑Cyber. They're also extending a program they launched in February (which I had missed) called Trusted Access for Cyber, where users can verify their identity (via a photo of a government-issued ID processed by Persona) to gain "reduced friction" access to OpenAI's models for cybersecurity work. Honestly, this OpenAI announcement is difficult to follow. Unsurprisingly they don't mention Anthropic at all, but much of the piece emphasizes their many years of existing cybersecurity work and their goal to "democratize access" to these tools, hence the emphasis on that self-service verification flow from February. If you want access to their best security tools you still need to go through an extra Google Form application process though, which doesn't feel particularly different to me from Anthropic's Project Glasswing. Posted 14th April 2026 at 9:23 pm Recent articles Meta's new model is Muse Spark, and meta.ai chat has some interesting tools - 8th April 2026 Anthropic's Project Glasswing - restricting Claude Mythos to security researchers - sounds necessary to me - 7th April 2026 The Axios supply chain attack used individually targeted social engineering - 3rd April 2026 This is a link post by Simon Willison, posted on 14th April 2026. security 596 ai 1960 openai 406 generative-ai 1740 llms 1707 anthropic 268 ai-security-research 14 Monthly briefing Sponsor me for $10/month and get a curated email digest of the month's most important LLM developments. Pay me to send you less! Sponsor & subscribe Disclosures Colophon © 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026