> ## 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.

# MCP Integration

> Use TinyFn tools with AI assistants via MCP

# 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 →](/docs/mcp/categories)

<Warning>
  **Trailing Slash Required**

  URLs **must** end with `/` or you'll get 404 errors:

  * ✅ `https://api.tinyfn.io/mcp/math/`
  * ❌ `https://api.tinyfn.io/mcp/math`
</Warning>

## 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                                                                                                  |

<Tip>
  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.
</Tip>

## Quick Start

### 1. Get an API Key

Sign up at [tinyfn.io](https://tinyfn.io) to get your API key.

### 2. Configure Your Client

<Tabs>
  <Tab title="Claude Desktop">
    Add to `~/Library/Application Support/Claude/claude_desktop_config.json`:

    ```json theme={null}
    {
      "mcpServers": {
        "tinyfn-math": {
          "url": "https://api.tinyfn.io/mcp/math/",
          "headers": {
            "X-API-Key": "tf_live_YOUR_KEY_HERE"
          }
        }
      }
    }
    ```
  </Tab>

  <Tab title="Cursor / Windsurf">
    Add to your MCP config:

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

    <Note>Use `validate` (15 tools), `hash` (18), or `encode` (20) for Cursor/Windsurf's 40-tool limit.</Note>
  </Tab>

  <Tab title="Continue.dev">
    Add to your Continue config:

    ```json theme={null}
    {
      "experimental": {
        "mcpServers": [
          {
            "name": "tinyfn",
            "url": "https://api.tinyfn.io/mcp/math/",
            "headers": {
              "X-API-Key": "tf_live_YOUR_KEY_HERE"
            }
          }
        ]
      }
    }
    ```
  </Tab>
</Tabs>

### 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:

1. Your API key starts with `tf_live_`
2. The `X-API-Key` header is included
3. 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}
```