Configuration¶

Tip

The configuration format is still evolving. Backwards compatibility is maintained where possible, but some keys may change between minor versions. Check the release notes when upgrading.

Language Check is configured via a .languagecheck.yaml file in your workspace root. YAML is preferred; .languagecheck.yml and .languagecheck.json are also supported.

Engines¶

Control which checking engines are active:

engines:
  # Bool shorthand — just enable/disable:
  harper: true
  languagetool: false

  # Nested config — engine-specific settings:
  harper:
    enabled: true
    dialect: "American"       # American | British | Canadian | Australian | Indian
    linters:
      LongSentences: false    # Disable specific Harper rules

  languagetool:
    enabled: true
    url: "http://localhost:8010"
    level: "picky"            # "default" or "picky" (stricter rules)
    mother_tongue: "de-DE"    # For false-friends detection
    disabled_rules:
      - WHITESPACE_RULE
    enabled_rules: []
    disabled_categories: []
    enabled_categories: []

  vale:
    enabled: true
    config: ".vale.ini"       # Path to Vale config (auto-detected if omitted)

  proselint:
    enabled: false
    config: "proselint.json"  # Path to proselint config (auto-detected if omitted)

  spell_language: "en-US"     # BCP-47 tag for checking language

Both bool shorthand (harper: true) and nested config (harper: { enabled: true, dialect: "British" }) are supported. Use the shorthand when you only need to toggle an engine; use the nested form when you need engine-specific settings.

Note

Harper is built in and requires no external installation. LanguageTool, Vale, and Proselint are external tools that must be installed separately and available on your $PATH. See the dedicated setup guides:

The inspector health tab in VS Code shows whether each engine’s binary was detected and provides install instructions when missing.

All enabled engines run concurrently and their diagnostics overlay. Engines that don’t support the configured spell_language are automatically skipped (e.g. Harper only supports English). Duplicate diagnostics at the same range and rule are deduplicated.

Rule Overrides¶

Change severity or disable individual rules:

rules:
  spelling.typo:
    severity: warning    # error | warning | info | hint | off
  grammar.article:
    severity: "off"      # Disable this rule entirely

Exclude Patterns¶

Glob patterns to skip during workspace checking:

exclude:
  - "node_modules/**"
  - ".git/**"
  - "vendor/**"
  - "*.min.js"

Auto-Fix Rules¶

Define custom find-and-replace rules applied automatically:

auto_fix:
  - find: "teh"
    replace: "the"
    description: "Fix common typo"
  - find: "colour"
    replace: "color"
    context: "American"    # Only apply when "American" appears in the text

Performance¶

Tune performance for large workspaces:

performance:
  high_performance_mode: false  # Only use Harper (skip LT and externals)
  debounce_ms: 300              # LSP debounce delay
  max_file_size: 1048576        # Skip files larger than 1MB (0 = unlimited)

Full Example¶

Here’s a .languagecheck.yaml putting it all together:

engines:
  harper:
    enabled: true
    dialect: "American"
  languagetool:
    enabled: true
    url: "http://localhost:8010"
    level: "default"
  vale:
    enabled: true
    config: ".vale.ini"
  proselint: false
  spell_language: "en-US"
  external:
    - name: custom-checker
      command: ./my-checker
      extensions: [md, rst]

rules:
  spelling.typo:
    severity: warning
  grammar.article:
    severity: "off"

exclude:
  - "node_modules/**"
  - ".git/**"

auto_fix:
  - find: "teh"
    replace: "the"

performance:
  high_performance_mode: false
  debounce_ms: 300