Add validate_style_tool for offline Mapbox style validation

[mattpodwysocki]

Summary

Adds a new offline validation tool that validates Mapbox style JSON against the Mapbox Style Specification. This is the first in a series of offline validation/utility tools.

What's New

validate_style_tool

Purpose: Validate Mapbox style JSON without making API calls

Features:

• ✅ Comprehensive offline validation (no API access required, no token needed)
• ✅ Validates required fields (version, sources, layers)
• ✅ Checks valid layer types and source types
• ✅ Detects duplicate layer IDs
• ✅ Validates source references
• ✅ Identifies missing required properties
• ✅ Returns structured errors, warnings, and info messages with suggestions
• ✅ Provides style summary statistics

Input:

{
  style: MapboxStyleJSON | string  // Style object or JSON string
}

Output:

{
  valid: boolean,
  errors: Array<{ severity, message, path, suggestion }>,
  warnings: Array<{ severity, message, path, suggestion }>,
  info: Array<{ severity, message, path, suggestion }>,
  summary: {
    version: number,
    layerCount: number,
    sourceCount: number,
    hasSprite: boolean,
    hasGlyphs: boolean
  }
}

Testing

✅ 11 comprehensive test cases covering:

• Valid styles
• Missing required fields
• Invalid layer types
• Duplicate layer IDs
• Non-existent source references
• JSON string parsing
• Warnings and info messages
• Summary statistics

All tests passing.

Documentation

• ✅ Added to README.md with clear description
• ✅ Inline code documentation
• ✅ Schema descriptions for all fields

Architecture

• Pattern: Extends BaseTool (offline tool, no HttpRequest dependency)
• Validation: Input/output validated with Zod schemas
• Location: src/tools/validate-style-tool/

Future Work

This tool is part of a planned suite of offline validation tools:

• validate_geojson_tool
• validate_expression_tool
• compare_styles_tool
• check_color_contrast_tool
• optimize_style_tool

Each will be added in separate PRs for easier review.

Why This Matters

Offline validation tools provide:

• ⚡ Fast feedback (no network latency)
• 🔒 Privacy (data stays local)
• 💰 No API costs
• 🛡️ Catch errors before upload

Perfect for catching common mistakes before calling Mapbox APIs.

Testing

Test 1:

"Can you validate this Mapbox style for me?"

  {
    "version": 8,
    "sources": {},
    "layers": [
      {"id": "bg", "type": "background"}
    ]
  }

Claude will:

1. Use validate_style_tool
2. Report validation results
3. Suggest fixes for any issues

🤖 Generated with Claude Code