JetBrains has announced that KotlinLLM, its research prototype for delegating runtime logic to a large language model (LLM) from Kotlin code, will now be available as open source and will be public. Kotlin is the open source language originated by JetBrains and promoted by Google as a first class language for Android to replace or supplement Java. Kotlin LLM, which was announced in July, is an IntelliJ IDEA plugin prototype. It adds a language feature JetBrains calls smart macros, which can be used for code generation, runtime updates, and hot-reloading. The GitHub page for KotlinLLM says a smart macro is an explicit Kotlin call whose behavior is backed by generated Kotlin source code. When the running application reaches an unsupported scenario, the plugin can capture the runtime values, ask an LLM agent to generate a narrow implementation update, compile the changed source, and hot-reload the affected class through JDI. The developers say that the design goal is that LLM-backed behavior should be explicit at the call site, persistent as source code, and portable as ordinary Kotlin once generated. KotlinLLM has three layers, a public API, a static infrastructure and a dynamic infrastructure. The public API consists of two functions, one to convert a value from one type to another, and a second that creates an implementation of an interface whose behavior can evolve from runtime interactions. Unlike direct runtime delegation to an LLM service, Kot