io.tinyfn/tinyfn

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The Problem

LLMs are great at reasoning. They're terrible at math.

Ask any AI assistant to compute 17% of 4,847 and you'll get a confident, wrong answer. Ask it to validate an email with regex, generate a SHA-256 hash, or convert timezones — same story. LLMs hallucinate on deterministic tasks.

TinyFn is a Model Context Protocol (MCP) server that gives your AI assistant 500+ tools that always return the correct answer. Math, conversions, validations, hashing, date arithmetic — the boring stuff, done right.

🖥️ Works With Your Tools

TinyFn runs as a remote MCP server — no npx, no Docker, no local install. Just add the URL to your config.

💡 Why category servers? Most AI clients limit the number of tools. TinyFn splits 500+ tools across 12 focused servers so you can pick exactly what you need.

✅ Example Queries That Just Work

Once connected, just ask your AI assistant in plain language:

Math & Numbers

• ✅ "Is 7919 a prime number?"
• ✅ "What's 17% of 4,847?"
• ✅ "Calculate the factorial of 12"

Conversions

• ✅ "Convert 72°F to Celsius"
• ✅ "How many miles is 100 kilometers?"
• ✅ "Convert #3B82F6 to RGB values"

Validation

• ✅ "Is user@example.com a valid email address?"
• ✅ "Validate this credit card number: 4111111111111111"
• ✅ "Is 550e8400-e29b-41d4-a716-446655440000 a valid UUID?"

Encoding & Hashing

• ✅ "Base64 encode 'Hello, World!'"
• ✅ "Generate a SHA-256 hash of 'my-secret-string'"
• ✅ "URL encode 'hello world & goodbye'"

Date & Time

• ✅ "How many days between January 15 and March 22?"
• ✅ "What's the current Unix timestamp?"
• ✅ "Is 2024 a leap year?"

Generators

• ✅ "Generate a UUID"
• ✅ "Create a secure 20-character password"
• ✅ "Roll 3 six-sided dice"

⚡ Quick Start

1. Get your free API key at tinyfn.io (takes 10 seconds)

2. Add TinyFn to your MCP client:

Claude Code

Claude Code supports Tool Search, so you can use the full server with all 500+ tools:

{
  "mcpServers": {
    "tinyfn": {
      "url": "https://api.tinyfn.io/mcp/all/",
      "headers": {
        "X-API-Key": "tf_live_YOUR_KEY_HERE"
      }
    }
  }
}

Add this to ~/.claude/settings.json or use claude mcp add.

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "tinyfn-math": {
      "url": "https://api.tinyfn.io/mcp/math/",
      "headers": {
        "X-API-Key": "tf_live_YOUR_KEY_HERE"
      }
    },
    "tinyfn-validate": {
      "url": "https://api.tinyfn.io/mcp/validate/",
      "headers": {
        "X-API-Key": "tf_live_YOUR_KEY_HERE"
      }
    }
  }
}

Tip: Claude Desktop supports ~100 tools. Add 2–3 category servers based on your workflow.

Cursor & Windsurf

These platforms have a ~40 tool limit. Pick 1–2 focused servers:

{
  "mcpServers": {
    "tinyfn-validate": {
      "url": "https://api.tinyfn.io/mcp/validate/",
      "headers": {
        "X-API-Key": "tf_live_YOUR_KEY_HERE"
      }
    }
  }
}

Recommended for Cursor/Windsurf: validate (15 tools), hash (18 tools), encode (20 tools), convert (42 tools).

Continue.dev

{
  "experimental": {
    "mcpServers": [
      {
        "name": "tinyfn-math",
        "url": "https://api.tinyfn.io/mcp/math/",
        "headers": {
          "X-API-Key": "tf_live_YOUR_KEY_HERE"
        }
      }
    ]
  }
}

3. Start asking questions. Your AI now has deterministic tools for math, conversions, validation, and more.

📡 Available MCP Servers

All servers use base URL https://api.tinyfn.io. Pick the categories you need:

⚠️ Important: All URLs must end with a trailing / or requests will return 404 errors.

🛠️ Tool Categories

🎯 Perfect For

• AI-Assisted Development — Cursor and Windsurf users who need reliable math in their coding workflow
• Data Analysis — Statistics, percentiles, and financial calculations without second-guessing
• Content Creation — Word counts, slugification, and encoding when building with AI
• DevOps & Security — Hash generation, UUID creation, and input validation
• Education — Teach with tools that demonstrate correct mathematical results
• API Development — Validate inputs, generate test data, and compute values during development

💰 Pricing

🔧 Troubleshooting

All MCP server URLs must end with a trailing slash /.

✅ https://api.tinyfn.io/mcp/math/
❌ https://api.tinyfn.io/mcp/math

1. Verify your API key starts with tf_live_
2. Check that you're using the X-API-Key header (not Authorization)
3. Make sure your key is active at tinyfn.io/dashboard

{
  "headers": {
    "X-API-Key": "tf_live_YOUR_KEY_HERE"
  }
}

Your MCP client has a tool limit. Instead of /mcp/all/, use category-specific servers:

See the full server list for all options.

You've hit your plan's rate limit. Options:

• Free tier: 10 requests/minute, 100/month — upgrade at tinyfn.io
• Starter: 100 requests/minute, 10,000/month
• Check your current usage at tinyfn.io/dashboard

📚 Documentation & Resources

• MCP Overview — Setup guide for all supported platforms
• API Reference — REST API docs for direct HTTP usage
• MCP Categories — Detailed breakdown of each server
• Authentication — API key setup and management
• Rate Limits — Quotas and limits per plan
• LLM Context — llms.txt for AI-readable documentation

🤝 Support

• 📧 Email: support@tinyfn.io
• 🐛 Issues: GitHub Issues
• 💬 Sales: sales@tinyfn.io

📄 License

MIT License — see LICENSE for details.