On September 15, 2026, Carter Leffer successfully validated a breakthrough of the German Army Enigma message MVUEH (Nr. 172), which had remained undeciphered since 2005. The decryption was achieved autonomously by the GPT–6 Astra model after it identified the message as a high-priority target from the Crypto Cellar Research database. The AI deduced a potential relationship between MVUEH and the previously broken message SIPVX (Nr. 173), noting that their plaintexts were nearly identical despite differing in length (82 versus 94 letters) due to a transcription error in the word "Bitte" and a repeated signature. To execute the break, GPT–6 Astra developed its own Python and C++ software to simulate an Enigma machine and an Enigma Bombe, ultimately utilizing the repeated place name "ROSENOW" as a crib. The resulting key differed significantly from the standard daily key for July 10, 1941; specifically, the wheel order was 253 rather than 512. The difficulty of the message was compounded by errors in the original ciphertext transcription and a rare turnover of the Enigma's left-hand wheel at the 72nd letter. Notably, the model appeared to leverage external historical context, referencing specific Bundesarchiv file collections (RS 3–3/20a and RS 3–3/63b) to inform its cryptanalytic approach.