Configuration File

FSH Lint uses a fsh-lint.json or fsh-lint.jsonc configuration file.

Creating a Config File

Run the init command to create a default configuration:

fsh-lint init

This creates fsh-lint.json in your current directory with recommended defaults.

Config File Format

Basic Configuration

{
  "$schema": "https://octofhir.github.io/fsh-lint-rs/schema/v1.json",
  "root": true,
  "linter": {
    "enabled": true,
    "rules": {
      "recommended": true
    }
  }
}

Full Configuration

{
  "$schema": "https://octofhir.github.io/fsh-lint-rs/schema/v1.json",
  "root": true,

  // Extend from base config
  "extends": ["./configs/base.json"],

  "linter": {
    "enabled": true,
    "rules": {
      // Enable all recommended rules
      "recommended": true,

      // Configure specific rules
      "correctness": {
        "duplicate-definition": "error",
        "required-fields": "warn"
      },
      "style": {
        "naming-convention": "warn"
      }
    },

    // Load custom GritQL rules
    "ruleDirectories": ["./custom-rules"]
  },

  "formatter": {
    "enabled": true,
    "indentSize": 2,
    "lineWidth": 100
  },

  "files": {
    "include": ["**/*.fsh"],
    "exclude": ["**/node_modules/**", "**/temp/**"]
  }
}

Configuration Options

Schema Reference

The $schema field enables IDE autocomplete and validation:

{
  "$schema": "https://octofhir.github.io/fsh-lint-rs/schema/v1.json"
}

Root Flag

Set root: true to stop upward config file search:

{
  "root": true
}

Extends

Inherit from other config files:

{
  "extends": ["./base.json", "@my-org/fsh-config"]
}

Auto-Discovery

FSH Lint automatically searches for config files by:

Starting from current directory
Looking for fsh-lint.jsonc or fsh-lint.json
Moving up to parent directories
Stopping at root: true or filesystem root

JSONC Support

Use comments and trailing commas in .jsonc files:

{
  // This is a comment
  "linter": {
    "enabled": true,  // Trailing comma OK
  }
}