KotlinLLM, a research prototype for delegating runtime logic to a large language model (LLM) from Kotlin code, is now going open source and public, JetBrains announced.
Revealed July 28, KotlinLLM is an IntelliJ IDEA plugin prototype for experimenting with LLM-driven “Smart macros” in Kotlin, enabling code generation, runtime updates, and hot-reloading. In software engineering, LLMs are commonly used during development for code completion, code generation, and program comprehension, JetBrains noted, but using an LLM at run time of a compiled application is much less common. The existing options for doing this have the following trade-offs, according to JetBrains:
- Direct runtime delegation is slow, non-deterministic, and costly, and makes the application depend on an LLM service at run time.
- External agent workflows keep the generated logic outside the codebase, where it is harder to review, test, and ship.
- Most prior work (byLLM, nightjar, Healer) targets interpreted languages like Python, not a compiled, statically typed language like Kotlin.
KotlinLLM addresses these limitations in three ways, JetBrains said:
- The call site shows that a feature is LLM-backed, so it is visible in code review.
- Generated behavior is saved as an ordinary Kotlin source, not kept only in the runtime session. It can be committed, reviewed, tested, and distributed like any other code.
- Once generated, the code runs as plain Kotlin without the plugin. For scenarios that are already covered, there is no further LLM call, so no added latency or cost, and the result is reproducible.
KotlinLLM is open source under Apache License 2.0. The repository contains the KotlinLLM IntelliJ IDEA plugin, the Smart macro API, and example projects.