The HMS Canterbury cruiser's arrival in Sevastopol was identified after GPT-6 Astra broke a previously mysterious World War I radio message. The deciphered text confirms that an allied squadron arrived on Nov. 26, 1918, and the original transmission was listed among approximately 20 German messages on a list of the top 50 unsolved ciphers.

The AI validated the result by searching for and analyzing historical ship logs provided as JPG images. The message was transmitted on Nov. 27, 1918, creating a discrepancy with historical records that indicate the specific encryption key was not utilized by German forces until Dec. 9.