copilot-instructions

Use when implementing any feature or fix using TDD, before writing any implementation code

Use when domain logic leaks into API/Infrastructure, project references violate layer boundaries, or you need to decide between CQS (always), CQRS bus (complex domains), and DDD patterns (invariants and events).

Use when configuring Git hooks in .NET projects before team commits occur, to enforce commit message standards and code formatting automatically

Use before writing any test or implementation task, when observable behavior needs to be captured in business language scenarios and approved by the user before code begins

Use when running mutation testing, killing mutants, verifying test quality, checking mutation score, or analyzing survivors after the test baseline is green

Use when writing tests from the outside-in, defining behavior before code, or any feature where tests should start from observable business behavior and let internal design emerge

Use when understanding project composition by language, measuring code change impact, or generating code statistics for CI/CD metrics

Use when editing code structure with text matching ambiguity, handling "old_string not unique" problems, or performing formatting-independent pattern matching across function signatures, method calls, and class structures

Use when listing all methods, functions, or classes in a file, exploring unfamiliar code, getting API overviews, or deciding what to read selectively without loading entire files

Use when searching for files by name, pattern, or type in large directories, or building file lists for pipelines with other tools

Use when choosing interactively from search results, files, processes, or any command output with preview capabilities

Use when querying JSON files, filtering or transforming JSON data, or extracting specific fields from large JSON files without loading entire file contents (saves 80-95% context)

Use when querying YAML files, filtering or transforming configuration data, or extracting specific fields from large YAML files like docker-compose.yml or GitHub Actions workflows without loading entire files (saves 80-95% context)

Use when performing text find & replace, batch transformations across files, or when JavaScript-style regex syntax is preferred over sed

Use when searching for text patterns across files, finding specific code locations, or getting lines with surrounding context in a single call

Use when setting up snip CLI token reduction hooks in a project, before first terminal commands are run

Use when viewing source files or documentation with syntax highlighting, previewing files with Git integration, or when enhanced readability would improve code review

Use when creating OpenAPI mock examples for Microcks, setting up request/response routing with dispatchers, or mapping request fields to mock responses

Use when converting existing .prompt.md or .instructions.md files to reusable SKILL.md format, before guessing structure or deciding what to keep/remove

Guide for creating effective skills. This skill should be used when users want to create a new skill (or update an existing skill) that extends Codex's capabilities with specialized knowledge, workflows, or tool integrations.