MCP Server

The ToolBox MCP (Model Context Protocol) server lets AI assistants like Claude Desktop, Cursor, and other MCP-compatible clients call ToolBox tools directly. Instead of copy-pasting between your AI assistant and ToolBox, the assistant can format JSON, hash strings, generate UUIDs, run DNS lookups, analyze SEO, and more on its own.

The dev utilities (formatters, encoders, UUID, hashing, etc.) run locally over stdio and are free forever. The network-backed tools call the ToolBox REST API; they currently work without a key during the public launch, with Pro-gated rate limits coming in a future release. Pro subscription supports future development.

What's included

The MCP server exposes 27 tools split into two groups.

Dev utilities (run locally, no API key needed)

Tool	Description
json_format	Pretty-print JSON with configurable indent and optional key sorting
json_minify	Strip whitespace from JSON into a single compact line
base64_encode	Base64-encode UTF-8 text (standard or URL-safe)
base64_decode	Decode base64 (or URL-safe base64) to UTF-8
url_encode	Percent-encode a string using encodeURIComponent rules
url_decode	Decode a percent-encoded string
hash_text	Compute MD5, SHA1, SHA256, or SHA512 hex digest of text
uuid_generate	Generate UUID v4 (random) or v7 (time-sortable), 1-100 at a time
slugify	Convert text to a URL-friendly slug (lowercase, hyphens, diacritics stripped)
case_convert	Convert between camel, pascal, snake, kebab, constant, title, sentence, upper, lower
regex_test	Test a regex against text, return matches with capture groups
timestamp_convert	Convert between Unix timestamps (s or ms) and ISO 8601
jwt_decode	Decode a JWT's header and payload (does not verify signature)
lorem_ipsum	Generate placeholder text by words, sentences, or paragraphs
color_convert	Convert between hex, rgb, and hsl (accepts any, returns all)

Network tools (call the ToolBox REST API)

Tool	Description
dns_lookup	DNS records (A, AAAA, MX, TXT, CNAME, NS) with optional WHOIS data
ssl_check	SSL/TLS certificate details - issuer, expiry, days remaining
headers_check	Fetch and inspect HTTP response headers for any URL
speed_test	PageSpeed Insights audit - performance scores, Core Web Vitals
check_links	Check if URLs are reachable (up to 20 URLs at once)
redirect_check	Trace the full redirect chain for a URL (up to 10 hops)
seo_analyze	SEO analysis - title, meta, headings, images, structured data, score out of 100
url_safety_check	Safety analysis - SSL, redirects, domain patterns, security headers
og_fetch	Fetch Open Graph, Twitter Card, and other meta tags from a URL
exchange_rates	Latest currency exchange rates or historical time series
grammar_check	Grammar, spelling, and style checking via LanguageTool
translate	Translate text between languages via MyMemory API

Installation

Prerequisites

• Node.js 18 or later
• A ToolBox Pro API key is optional during the open launch

Build from source

The MCP server lives in the mcp-server/ directory of the ToolBox repository.

cd mcp-server
npm install
npm run build

This compiles TypeScript to dist/index.js.

Configuration

The server uses two environment variables:

Variable	Required	Default	Description
TOOLBOX_API_KEY	No	(empty)	Your ToolBox Pro API key (optional during the open launch)
TOOLBOX_API_URL	No	https://www.toolbox-kit.com/api	API base URL (override for testing)

Setup with Claude Desktop

Add this to your Claude Desktop configuration file:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "toolbox": {
      "command": "node",
      "args": ["/absolute/path/to/mcp-server/dist/index.js"],
      "env": {
        "TOOLBOX_API_KEY": "tb_your_api_key_here"
      }
    }
  }
}

Replace /absolute/path/to/mcp-server/dist/index.js with the actual path to your built server.

After saving, restart Claude Desktop. You should see the ToolBox tools in the tool picker.

Setup with Cursor

In Cursor settings, add the MCP server under Settings > MCP Servers:

{
  "mcpServers": {
    "toolbox": {
      "command": "node",
      "args": ["/absolute/path/to/mcp-server/dist/index.js"],
      "env": {
        "TOOLBOX_API_KEY": "tb_your_api_key_here"
      }
    }
  }
}

Setup with Claude Code

Add the server using the CLI:

claude mcp add toolbox -- node /absolute/path/to/mcp-server/dist/index.js

Set the environment variable before running:

export TOOLBOX_API_KEY="tb_your_api_key_here"

Usage examples

Once connected, you can ask your AI assistant things like:

• "Format this JSON and sort the keys"
• "Base64 encode this secret"
• "Generate 5 UUID v7s"
• "What's the SHA256 of this string?"
• "Decode this JWT and show me the payload"
• "Convert #10b981 to hsl"
• "Check the DNS records for example.com"
• "Is the SSL certificate for my-site.com about to expire?"
• "Run an SEO analysis on https://my-site.com/blog"
• "Check if these 5 URLs are returning 200s" (passes them to check_links)
• "What's the redirect chain for http://old-domain.com?"
• "Translate this paragraph to French"

The assistant will call the appropriate ToolBox MCP tool and return the results inline.

Example: DNS Lookup

When you ask "Look up the MX records for gmail.com", the assistant calls:

{
  "tool": "dns_lookup",
  "arguments": {
    "domain": "gmail.com",
    "type": "MX"
  }
}

Example: SEO Analysis

When you ask "Analyze the SEO of https://example.com", the assistant calls:

{
  "tool": "seo_analyze",
  "arguments": {
    "url": "https://example.com"
  }
}

The response includes title analysis, meta description, heading structure, image alt text coverage, structured data, internal/external links, and an overall score.

Running standalone

You can also run the MCP server directly for testing:

TOOLBOX_API_KEY=tb_your_key node mcp-server/dist/index.js

The server communicates over stdio using the MCP protocol, so it won't produce visible output on its own - it's designed to be called by an MCP client.

Troubleshooting

"API error 401" - Your TOOLBOX_API_KEY is missing or invalid. Check that the environment variable is set correctly in your MCP client config.

"API error 429" - You've hit the rate limit. The MCP server respects the same rate limits as the REST API. See Rate Limits for details.

Tools not showing up in Claude Desktop - Make sure you've restarted Claude Desktop after editing the config. Check the path to dist/index.js is correct and absolute.

"Cannot find module" errors - Run npm run build in the mcp-server/ directory first. The server needs to be compiled from TypeScript before use.