Language Check

A fast, multi-engine prose linter for VS Code and Neovim with a Rust core.

Language Check catches grammar, spelling, and style issues in Markdown, HTML, LaTeX, Typst, reStructuredText, Org mode, BibTeX, Forester, and R Sweave files using Harper, optional LanguageTool, optional Vale, and optional Proselint integration.

VS Code

Neovim

Early Development

Language Check is in active early development. Core checking is stable and usable, but you may encounter bugs — please report them and they will be fixed promptly. The configuration format may change between minor versions; backwards compatibility is a goal but not yet guaranteed.

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User Guide

• Installation
  • VS Code Extension
  • CLI Binary
• Neovim Setup
  • Installing the Binary
  • Plugin Installation
  • Configuration
  • Workspace Configuration
  • Commands
  • Health Check
  • Diagnostics
• LanguageTool Setup
  • Quick Start (Docker)
  • Install LanguageTool
  • Run as a System Service
  • Connect to Language Check
  • Multi-Engine Mode
  • Verify the Connection
  • Troubleshooting
• Vale Setup
  • Installing Vale
  • Enabling Vale
  • Vale Configuration
  • Style Packages
  • How it Works
  • Rule Overrides
  • High Performance Mode
• Proselint Setup
  • Installing Proselint
  • Enabling Proselint
  • Proselint Configuration
  • How it Works
  • Rule Overrides
  • High Performance Mode
• Configuration
  • Engines
  • Rule Overrides
  • Exclude Patterns
  • Auto-Fix Rules
  • Performance
  • Full Example
• Language Support
  • Supported File Types
  • Checking Languages
• Contributing Translations
  • Translating via Crowdin (Recommended)
  • Extension Localization
  • Documentation Localization
  • CI Checks
  • Current Languages
• Why Language Check?
  • Modern, accessible stack
  • Engine-agnostic by design
  • Fast because it should be
  • Tree-sitter grammars, not regex
  • Inspectable internals
  • Workspace-scale checking

Advanced

• Custom Providers
  • Configuration
  • Protocol
  • Error Handling
  • High Performance Mode
• WASM Plugins
  • Configuration
  • Plugin Interface
  • Plugin Discovery
  • Building Plugins
  • Error Handling
  • Rule ID Namespacing
• Extension API
  • Accessing the API
  • API Methods
  • Diagnostic Interface

Extending

• Adding Language Support via Config (No Code Required)
  • When to use an SLS schema
  • Where schema files live
  • Schema file format
  • Worked Example: AsciiDoc
  • Worked Example: TOML Notes
  • Built-in languages still win
  • When to use extension aliases instead
  • Limitations
• Adding Language Support via the Plugin Path
  • Overview
  • Prerequisites
  • Step-by-step Guide
  • Testing Strategy
  • Files Checklist
• Writing a WASM Plugin
  • Overview
  • Protocol
  • Setting Up
  • Writing the Plugin
  • Testing
  • Integrating with Language Check
  • Debugging
  • Other Languages
  • Reference Implementation
• TinyLang Specification
  • File Extension
  • Syntax
  • Example Document
  • Tree-Sitter Node Types

Reference

• CLI Reference
  • Usage
  • Commands
  • Exit Codes
• Configuration Schema
  • Top-Level Fields
  • Engines
  • External Providers
  • WASM Plugins
  • Rule Config
  • Auto-Fix
  • Performance
  • Languages
• Package Registry Publishing
  • crates.io
  • Homebrew (macOS/Linux)
  • winget (Windows)
  • AUR (Arch Linux)
  • Debian/Ubuntu (.deb)
  • Release Automation
• Troubleshooting
  • Common Issues
  • Debug Tools
  • Reporting Issues