Use this skill to review code. It supports both local changes (staged or working tree) and remote Pull Requests (by ID or URL). It focuses on correctness, maintainability, and adherence to project standards.
Write property-based tests using Hegel across Rust, Go, C++, and TypeScript projects. Use this skill whenever the user asks to write tests, add test coverage, or improve testing for functions, modules, or libraries — especially when the code has properties like round-trips, invariants, or contracts that hold across many inputs. Also triggers on: "property-based tests", "PBT", "hegel", "fuzz", "generative tests", "randomized testing", "test with random inputs", "shrinking", or when existing tests use proptest, quickcheck, rapid, gopter, rapidcheck, or fast-check.
Applies the Diataxis framework to create or improve technical documentation. Use when being asked to write high quality tutorials, how-to guides, reference docs, or explanations, when reviewing documentation quality, or when deciding what type of documentation to create. Helps identify documentation types using the action/cognition and acquisition/application dimensions.
This document instructs Claude Code to use `jj` (Jujutsu) instead of `git` for version control operations. jj is a Git-compatible VCS that provides a simpler mental model and powerful history editing.
Nullables — testing technique alternative to using mocking libraries. Use when writing unit tests, when code touches external I/O or state (HTTP, databases, files, clock, random) anywhere in its dependency chain, when making a system testable, or when tests are slow or flaky.
Implement observability using the Wide Events (Canonical Log Lines) pattern. Instead of scattering logs throughout a request, accumulate high-cardinality context and emit a single, highly-dimensional structured event per service boundary.
Comprehensive guide to software design based on "A Philosophy of Software Design" by John Ousterhout. Covers complexity management, deep modules, error handling, naming, documentation, general-purpose design, design process, and consistency conventions.
just is a handy command runner for saving and running project-specific commands. Features include recipe parameters, .env file loading, shell completion, cross-platform support, and recipes in arbitrary languages. This skill is triggered when the user says things like "create a justfile", "write a just recipe", "run just commands", "set up project automation with just", "understand justfile syntax", or "add a task to the justfile".