NATO's Cooperative Cyber Defence Centre of Excellence (CCDCOE) opened Crossed Swords 2026 in Tallinn, Estonia, on Monday; the exercise runs through Friday. More than 250 people from over 40 countries, NATO members and non-members alike, are taking part, drawn from national cyber forces and the units that support them.
New this year is a dedicated AI agent track: participants build agents, deploy them, assess them and work alongside them. The exercise environment runs on locally hosted models and, for the first time, also on Daybreak, OpenAI's cyber defense offering. "This year, that gets harder, because AI is now in the loop on both sides," said exercise director Jozef Kostelansky, stressing the need for human oversight.
More than 20 organizations from industry, academia and the non-profit sector support the exercise, among them Bitdefender, ESET, Elastic, Mandiant, OpenAI and the Red Cross. Participation has roughly doubled since 2022.