MCP Integration

TinyFn exposes its 500+ utility functions as MCP (Model Context Protocol) tools, allowing AI assistants like Claude to call TinyFn functions directly for accurate results.

Why Use MCP?

LLMs often hallucinate when doing:

Math: Large number arithmetic, floating point operations, decimal comparisons
Conversions: Unit conversions (UK vs US gallons, temperature)
Encoding: Base64, URL encoding, hash generation
Dates: Date calculations, timezone conversions
Counting: Character counting (how many ‘r’ in ‘strawberry’)

With TinyFn MCP, LLMs can call verified functions instead of guessing.

Available Servers

TinyFn provides category-based MCP servers to avoid overwhelming LLMs with 500+ tools:

Server	URL	Tools	Description
Math	`/mcp/math/`	52	Arithmetic, comparisons, trigonometry
Convert	`/mcp/convert/`	42	Unit conversions (temperature, length, weight)
Validate	`/mcp/validate/`	15	Email, URL, phone validation
String	`/mcp/string/`	33	String manipulation, character counting
Hash	`/mcp/hash/`	18	MD5, SHA256, etc.
Encode	`/mcp/encode/`	20	Base64, URL, HTML encoding
DateTime	`/mcp/datetime/`	24	Timestamps, formatting, relative time
Time	`/mcp/time/`	12	Timezone conversions, DST handling
Stats	`/mcp/stats/`	16	Mean, median, mode, variance, percentiles
All	`/mcp/all/`	500+	All tools combined

View all categories →

Trailing Slash RequiredURLs must end with / or you’ll get 404 errors:

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

Platform Tool Limits

Different AI platforms have different limits on how many MCP tools they can handle:

Platform	Tool Limit	Recommendation
Cursor	40 tools max	Use `validate` (15), `hash` (18), `encode` (20), or `string` (33). Avoid `math` (52) and `convert` (42) which exceed the limit.
Claude Desktop	~100 tools	Use 2-3 category servers
Claude Code	Context-based	Can use `/mcp/all/` with Tool Search
Windsurf	~40-50 tools	Same as Cursor recommendations

For best results, add only the category servers you need rather than using /mcp/all/. This keeps the tool list manageable and helps the AI select the right tool.

Quick Start

1. Get an API Key

2. Configure Your Client

Claude Desktop
Cursor / Windsurf
Continue.dev

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

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

Add to your MCP config:

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

Use validate (15 tools), hash (18), or encode (20) for Cursor/Windsurf’s 40-tool limit.

Add to your Continue config:

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

3. Use It

Ask your AI assistant to do math, conversions, or other tasks. It will automatically use TinyFn tools when appropriate. Example:

You: What's 123456789 * 987654321?
AI: [calls tinyfn multiply tool]
    The result is 121,932,631,112,635,269

You: How many r's are in strawberry?
AI: [calls tinyfn count-char tool]
    There are 3 r's in "strawberry" at positions 3, 9, and 10.

You: Is 0.9 greater than 0.11?
AI: [calls tinyfn compare tool]
    Yes, 0.9 is greater than 0.11. The difference is 0.79.

Rate Limits

MCP requests count against your normal TinyFn rate limits:

Plan	Requests/Month	Requests/Minute
Free	100	10
Starter	10,000	100
Pro	100,000	1,000

Authentication Errors

If you see auth errors, verify:

Your API key starts with tf_live_
The X-API-Key header is included
Your key hasn’t been revoked

Example Tools

Math Tools

add(numbers: "1,2,3,4,5") → {"sum": 15}
multiply(numbers: "2,3,4") → {"product": 24}
compare(a: 0.9, b: 0.11) → {"a_is_greater": true, "difference": 0.79}
is_prime(number: 17) → {"is_prime": true}

String Tools

count_char(text: "strawberry", char: "r") → {"count": 3, "positions": [2, 8, 9]}
count_substring(text: "banana", substring: "an") → {"count": 2}

Conversion Tools

celsius_to_fahrenheit(celsius: 100) → {"fahrenheit": 212}
km_to_mi(kilometers: 10) → {"miles": 6.2137}

​MCP Integration

​Why Use MCP?

​Available Servers

​Platform Tool Limits

​Quick Start

​1. Get an API Key

​2. Configure Your Client

​3. Use It

​Rate Limits

​Authentication Errors

​Example Tools

​Math Tools

​String Tools

​Conversion Tools

MCP Integration

Why Use MCP?

Available Servers

Platform Tool Limits

Quick Start

1. Get an API Key

2. Configure Your Client

3. Use It

Rate Limits

Authentication Errors

Example Tools

Math Tools

String Tools

Conversion Tools