skills

Scala auto-derivation with Kindlings for Circe and PureConfig. Use when replacing circe-generic/circe-generic-extras or PureConfig generic derivation with Kindlings while keeping normal Circe JSON APIs and PureConfig loading/writing APIs.

Helps agents write and review Scala Cats Effect IO code. Use for suspending side effects and non-determinism in IO or F[_], choosing Sync/Async/Temporal/Concurrent/Clock/Random, handling blocking I/O, testing with TestControl, and composing resources, fibers, races, and structured concurrency safely.

Helps agents write and review Scala Cats Effect Resource code. Use for preventing resource leaks and use-after-release bugs, modeling disposable values with Resource, designing Resource-returning factories and constructor-injected services, wrapping Java AutoCloseable values, composing resources, and handling cancellation-safe release.

JSpecify nullness annotations for Java APIs and tooling. Use when adopting or migrating JSpecify annotations, designing null-safe Java signatures, fixing generic bounds and type-use placement, or interpreting Kotlin interop, annotation-processor, and tool-conformance behavior.

Helps agents design and review Kotlin library APIs for Java consumers. Use when building Kotlin code intended for Java callers, shaping JVM signatures with @JvmName, @JvmOverloads, @JvmStatic, @JvmField, @Throws, @JvmRecord, nullability, records, and backward/binary compatibility rules.

Guide for creating effective agent skills. Use when users want to create a new skill (or update an existing skill) that extends agent capabilities with specialized knowledge, workflows, or tool integrations.

Scala reactive streaming with Akka Streams and Pekko Streams. Use for dataflow and reactive programming patterns, testing stream components, and understanding when NOT to use streams (prefer plain functions for transformations and I/O).

Scala typed errors with Cats MTL Raise/Handle and allow/rescue. Use for designing custom domain error types without EitherT, while keeping Cats Effect and ecosystem composition. Covers Scala 2/3 syntax and IO-only or F[_] usage.