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.

Platform	Tool Limit	Recommended Setup	Config Location
Claude Code	500+ (Tool Search)	`/mcp/all/` — use everything	`~/.claude/settings.json`
Claude Desktop	~100 tools	2–3 category servers	`~/Library/Application Support/Claude/claude_desktop_config.json`
Cursor	~40 tools	1–2 focused servers	Cursor MCP settings
Windsurf	~40 tools	1–2 focused servers	Windsurf MCP settings
Continue.dev	Varies	Category servers	`.continue/config.json`
Any MCP Client	Varies	Match to your tool limit	Client-specific

💡 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:

Server	Endpoint	Tools	What It Does
All	`/mcp/all/`	500+	Everything — best for Claude Code
Math	`/mcp/math/`	52	Arithmetic, trig, primes, factorials, comparisons
Convert	`/mcp/convert/`	42	Temperature, length, weight, volume, speed, data sizes
String	`/mcp/string/`	33	Case conversion, slugify, trim, word count, extraction
Datetime	`/mcp/datetime/`	24	Date parsing, formatting, diffs, timezones, leap years
Encode	`/mcp/encode/`	20	Base64, URL, HTML, hex, ROT13, morse, JWT decode
Hash	`/mcp/hash/`	18	MD5, SHA-256, SHA-512, HMAC, bcrypt, CRC32
Color	`/mcp/color/`	30	HEX/RGB/HSL conversion, gradients, contrast, palettes
Stats	`/mcp/stats/`	16	Mean, median, mode, std dev, percentiles, correlation
Validate	`/mcp/validate/`	15	Email, URL, phone, credit card, UUID, IP, JSON, dates
Finance	`/mcp/finance/`	15	Interest, loans, mortgage, ROI, margin, tip calculator
Generate	`/mcp/generate/`	15	UUIDs, passwords, random numbers, lorem ipsum, dice

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

🛠️ Tool Categories

Tool	Description	Example
`add`, `subtract`, `multiply`, `divide`	Basic arithmetic	`add(17, 25)` → `42`
`percentage`	Percentage calculation	`percentage(17, 4847)` → `823.99`
`is_prime`	Primality testing	`is_prime(7919)` → `true`
`factorial`	Factorial calculation	`factorial(12)` → `479001600`
`fibonacci`	Nth Fibonacci number	`fibonacci(10)` → `55`
`gcd`, `lcm`	GCD and LCM	`gcd(48, 18)` → `6`
`power`, `square_root`	Exponentiation	`square_root(144)` → `12`
`sin`, `cos`, `tan`	Trigonometric functions	`sin(1.5708)` → `1.0`
`log`, `log10`, `log2`	Logarithms	`log10(1000)` → `3`
`floor`, `ceil`, `round_number`	Rounding	`ceil(4.2)` → `5`
`absolute_value`, `sign`	Number properties	`sign(-42)` → `-1`
`clamp`, `distance`, `hypotenuse`	Range & geometry	`hypotenuse(3, 4)` → `5`

Tool	Description	Example
`reverse_string`	Reverse text	`reverse_string("hello")` → `"olleh"`
`uppercase`, `lowercase`	Case conversion	`uppercase("hello")` → `"HELLO"`
`camel_case`, `snake_case`, `kebab_case`	Naming conventions	`snake_case("helloWorld")` → `"hello_world"`
`slug`	URL-safe slugs	`slug("Hello World!")` → `"hello-world"`
`trim`, `pad`	Whitespace handling	`trim(" hi ")` → `"hi"`
`word_count`, `string_length`	Text metrics	`word_count("hello world")` → `2`
`contains`, `starts_with`, `ends_with`	String matching	`contains("hello", "ell")` → `true`
`split`, `join`	Array operations	`split("a,b,c", ",")` → `["a","b","c"]`
`extract_emails`, `extract_urls`	Content extraction	Extract emails from text blocks
`is_palindrome`	Palindrome check	`is_palindrome("racecar")` → `true`
`count_char`, `count_substring`	Character counting	`count_char("hello", "l")` → `2`

Tool	Description	Example
`validate_email`	Email format validation	`validate_email("user@example.com")` → `true`
`validate_url`	URL format validation	`validate_url("https://tinyfn.io")` → `true`
`validate_phone`	Phone number validation	`validate_phone("+1-555-123-4567")` → `true`
`validate_credit_card`	Luhn algorithm check	`validate_credit_card("4111111111111111")` → `true`
`validate_uuid`	UUID format validation	`validate_uuid("550e8400-e29b-41d4-a716-446655440000")` → `true`
`validate_ip`	IPv4/IPv6 validation	`validate_ip("192.168.1.1")` → `true`
`validate_json`	JSON syntax validation	`validate_json('{"key": "value"}')` → `true`
`validate_date`	Date format validation	`validate_date("2024-02-29")` → `true`
`validate_hex`	Hex string validation	`validate_hex("1a2b3c")` → `true`
`validate_base64`	Base64 validation	`validate_base64("SGVsbG8=")` → `true`

Tool	Description	Example
`celsius_to_fahrenheit`	Temperature	`celsius_to_fahrenheit(100)` → `212`
`kilometers_to_miles`	Distance	`kilometers_to_miles(100)` → `62.14`
`kilograms_to_pounds`	Weight	`kilograms_to_pounds(70)` → `154.32`
`liters_to_gallons_us`	Volume	`liters_to_gallons_us(3.785)` → `1.0`
`hex_to_rgb`	Color	`hex_to_rgb("#3B82F6")` → `{r:59, g:130, b:246}`
`decimal_to_binary`	Base conversion	`decimal_to_binary(42)` → `"101010"`
`bytes_to_human`	File sizes	`bytes_to_human(1073741824)` → `"1 GB"`
`mph_to_kph`	Speed	`mph_to_kph(60)` → `96.56`
`inches_to_centimeters`	Length	`inches_to_centimeters(12)` → `30.48`
`hours_to_minutes`	Time	`hours_to_minutes(2.5)` → `150`

Tool	Description	Example
`hash_md5`	MD5 hash	`hash_md5("hello")` → `"5d41402abc4b..."`
`hash_sha256`	SHA-256 hash	`hash_sha256("hello")` → `"2cf24dba5fb0..."`
`hash_sha512`	SHA-512 hash	Full 128-char hex digest
`hmac_sha256`	HMAC signature	Keyed hash authentication
`hash_sha3_256`, `hash_sha3_512`	SHA-3 family	Modern hash algorithms
`hash_blake2b`, `hash_blake2s`	BLAKE2	High-performance hashing
`hash_crc32`	CRC32 checksum	Error detection codes
`compare_hashes`	Timing-safe compare	Constant-time hash comparison
`identify_hash`	Hash identification	Detect hash algorithm from string

Tool	Description	Example
`base64_encode`, `base64_decode`	Base64	`base64_encode("Hello")` → `"SGVsbG8="`
`url_encode`, `url_decode`	URL encoding	`url_encode("hello world")` → `"hello%20world"`
`html_encode`, `html_decode`	HTML entities	`html_encode("<div>")` → `"<div>"`
`hex_encode`, `hex_decode`	Hex encoding	`hex_encode("hi")` → `"6869"`
`jwt_decode`	JWT parsing	Decode JWT payload (no verification)
`rot13`	ROT13 cipher	`rot13("hello")` → `"uryyb"`
`morse_encode`, `morse_decode`	Morse code	`morse_encode("SOS")` → `"... --- ..."`
`json_minify`, `json_prettify`	JSON formatting	Minify or pretty-print JSON

Tool	Description	Example
`get_now`	Current timestamp	ISO 8601 timestamp
`format_date`, `parse_date`	Date formatting	Parse and format dates
`date_diff`	Days between dates	`date_diff("2024-01-15", "2024-03-22")` → `67 days`
`add_time`, `subtract_time`	Date arithmetic	Add/subtract days, hours, minutes
`convert_timezone`	Timezone conversion	Convert between any IANA timezones
`is_leap_year`	Leap year check	`is_leap_year(2024)` → `true`
`calculate_age`	Age from birthdate	Calculate exact age
`relative_time`	Relative formatting	`"2 hours ago"`, `"in 3 days"`
`days_in_month`	Month length	`days_in_month(2, 2024)` → `29`
`is_weekend`	Weekend check	Check if a date falls on Sat/Sun

Tool	Description	Example
`generate_uuid`	UUID v4	`"550e8400-e29b-41d4-a716-446655440000"`
`generate_uuid_v7`	UUID v7 (time-sortable)	Timestamp-based UUIDs
`generate_password`	Secure passwords	Configurable length and character sets
`random_number`	Random integers	`random_number(1, 100)` → `42`
`random_string`	Random strings	Configurable length and charset
`generate_token`	API tokens	Cryptographically secure tokens
`generate_lorem`	Lorem ipsum	Generate placeholder text
`generate_color`	Random colors	Random hex color codes
`roll_dice`	Dice rolling	`roll_dice(3, 6)` → `[4, 2, 6]`
`flip_coin`	Coin flip	`"heads"` or `"tails"`
`shuffle_list`	Shuffle arrays	Randomize array order

Tool	Description	Example
`hex_to_hsl`, `hsl_to_hex`	Color space conversion	Convert between formats
`hex_to_rgb`, `rgb_to_hex`	RGB conversion	`hex_to_rgb("#FF5733")` → `{r:255,g:87,b:51}`
`lighten_color`, `darken_color`	Brightness adjustment	Lighten/darken by percentage
`complement_color`	Complementary colors	Get the opposite color
`triadic_colors`, `analogous_colors`	Color harmonies	Generate color schemes
`contrast_ratio`	WCAG contrast	Check accessibility compliance
`generate_gradient`	Gradient generation	Generate color stops between two colors
`generate_shades`, `generate_tints`	Shade/tint ramps	Create monochromatic palettes
`invert_color`	Color inversion	Invert any hex color
`blend_colors`	Color blending	Mix two colors together

Tool	Description	Example
`calculate_mean`	Arithmetic mean	`calculate_mean([10, 20, 30])` → `20`
`calculate_median`	Median value	`calculate_median([1, 3, 5, 7])` → `4`
`calculate_mode`	Most frequent value	`calculate_mode([1, 2, 2, 3])` → `2`
`calculate_variance`	Population variance	Statistical variance
`calculate_stddev`	Standard deviation	Statistical spread
`calculate_percentile`	Percentile calculation	`calculate_percentile([1..100], 95)` → `95`
`calculate_quartiles`	Q1, Q2, Q3	Quartile boundaries
`calculate_correlation`	Pearson correlation	Correlation coefficient between datasets
`calculate_zscore`	Z-score	Standard score calculation
`describe_data`	Summary statistics	Full statistical description of a dataset

Tool	Description	Example
`compound_interest`	Compound interest	Calculate future value with compounding
`simple_interest`	Simple interest	Basic interest calculation
`loan_payment`	Loan payments	Monthly payment calculator
`mortgage_calculator`	Mortgage	Monthly mortgage with amortization
`calculate_tip`	Tip calculator	`calculate_tip(85.50, 20)` → `$17.10`
`percentage_change`	Growth/decline	`percentage_change(100, 125)` → `25%`
`calculate_markup`, `calculate_margin`	Pricing	Markup and margin calculations
`calculate_discount`	Discounts	Price after discount
`return_on_investment`	ROI	Investment return percentage
`rule_of_72`	Doubling time	Years to double an investment
`break_even`	Break-even analysis	Units needed to break even

Tool	Description	Example
`calculate_bmi`	Body Mass Index	`calculate_bmi(70, 1.75)` → `22.86`
`calculate_bmr`	Basal Metabolic Rate	Daily calorie baseline
`ideal_weight`	Ideal weight range	Based on height and frame
`heart_rate_zones`	Training zones	Fat burn, cardio, peak zones
`estimate_body_fat`	Body fat estimate	Navy method estimation
`daily_water_intake`	Water recommendation	Based on weight and activity
`calories_burned`	Exercise calories	Calories for activity type and duration
`calculate_macros`	Macro split	Protein/carb/fat breakdown
`sleep_cycles`	Sleep optimization	Optimal wake times based on cycles

Tool	Description	Example
`magic_8_ball`	Magic 8-Ball	Random mystical answers
`dad_joke`	Dad jokes	Guaranteed groan
`fortune_cookie`	Fortune cookies	Random fortune messages
`random_compliment`	Compliments	Brighten someone's day
`random_excuse`	Excuses	Creative excuse generator
`would_you_rather`	Would You Rather	Random dilemmas
`friendly_roast`	Friendly roasts	Light-hearted roasts
`random_trivia`	Trivia	Random trivia facts
`yes_no`	Yes/No oracle	Random yes or no

🎯 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

Verify your API key starts with tf_live_
Check that you're using the X-API-Key header (not Authorization)
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:

If you need...	Use server	Tools
Validation only	`/mcp/validate/`	15
Hashing only	`/mcp/hash/`	18
Encoding only	`/mcp/encode/`	20
Math only	`/mcp/math/`	52

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.