This VS Code extension provides comprehensive language support for the Crystal programming language. It includes syntax highlighting for Crystal, ECR (Embedded Crystal), and Slang templates, along with auto-indentation, snippets, and code formatting via the Crystal compiler's `tool format`. It integrates deeply with the Crystal toolchain to offer problems detection (compiler errors displayed inline), hover type information, go-to-definition, document symbols, and a macro expansion viewer. A task provider enables running common `crystal` and `shards` commands directly from the editor. A spec test explorer allows running and viewing Crystal spec results using the native VS Code testing UI, parsing JUnit XML output. The extension can optionally delegate to an external LSP server (e.g., Crystalline) for more advanced language intelligence. All language-aware features are implemented by spawning the Crystal compiler tool with appropriate flags and parsing its JSON/flat output, with careful management of compiler processes via mutexes and per-project cache directories. The source code is written in TypeScript and divided into modular providers (completion, definitions, hover, format, problems, symbols, tasks, spec).