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Documentation Index

Fetch the complete documentation index at: https://docs.tinyfn.io/docs/llms.txt

Use this file to discover all available pages before exploring further.

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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.

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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.

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Available Servers

TinyFn provides category-based MCP servers to avoid overwhelming LLMs with 500+ tools:
ServerURLToolsDescription
Math/mcp/math/52Arithmetic, comparisons, trigonometry
Convert/mcp/convert/42Unit conversions (temperature, length, weight)
Validate/mcp/validate/15Email, URL, phone validation
String/mcp/string/33String manipulation, character counting
Hash/mcp/hash/18MD5, SHA256, etc.
Encode/mcp/encode/20Base64, URL, HTML encoding
DateTime/mcp/datetime/24Timestamps, formatting, relative time
Time/mcp/time/12Timezone conversions, DST handling
Stats/mcp/stats/16Mean, 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

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Platform Tool Limits

Different AI platforms have different limits on how many MCP tools they can handle:
PlatformTool LimitRecommendation
Cursor40 tools maxUse validate (15), hash (18), encode (20), or string (33). Avoid math (52) and convert (42) which exceed the limit.
Claude Desktop~100 toolsUse 2-3 category servers
Claude CodeContext-basedCan use /mcp/all/ with Tool Search
Windsurf~40-50 toolsSame 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.

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Quick Start

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1. Get an API Key

Sign up at tinyfn.io to get your API key.

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2. Configure Your Client

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"
      }
    }
  }
}

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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.

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Rate Limits

MCP requests count against your normal TinyFn rate limits:
PlanRequests/MonthRequests/Minute
Free10010
Starter10,000100
Pro100,0001,000

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Authentication Errors

If you see auth errors, verify:
  1. Your API key starts with tf_live_
  2. The X-API-Key header is included
  3. Your key hasn’t been revoked

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Example Tools

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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}

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String Tools

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

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Conversion Tools

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