Stefanos Bou focused on backend development in the JetBrains/koog repository, where he addressed a targeted bug related to prompt handling. He corrected the tagging of system prompts in AgentMemory.kt, ensuring that prompts were accurately labeled as 'system' rather than 'user' to match their content type. This change improved the consistency and reliability of downstream prompt processing. Working primarily with Kotlin, Stefanos applied his expertise in the Kotlin and Java ecosystems to deliver a low-risk, auditable fix. His contribution maintained system stability and demonstrated careful attention to detail, though the scope was limited to a single, well-defined bug fix.