MCP Character Tools
The last thing you need for your LLM to work with individual characters or count the number of r's in a word. This is an MCP server providing 14+ comprehensive (and pretty) character and text analysis tools to help LLMs work with individual characters - something they struggle with due to tokenization.
See the Difference
| Without MCP (Wrong) | With MCP (Correct) |
|---|---|
 |  |
| Claims there are 2 r's in "garlic" | Correctly identifies 1 r in "garlic" |
Why This Exists
First of all, why not? Second, Large Language Models tokenize text into subwords, not individual characters. For example, "strawberry" might become tokens like ["straw", "berry"], so the model never truly "sees" individual letters. This MCP server gives LLMs "character-level vision" through a suite of tools.
Installation
Via npx (recommended)
npx mcp-character-tools
Via npm (global install)
npm install -g mcp-character-tools
mcp-character-tools
From source
git clone https://github.com/Aaryan-Kapoor/mcp-character-tools
cd mcp-character-tools
npm install
npm run build
npm start
Usage with Claude Desktop
Add to your Claude Desktop configuration (claude_desktop_config.json):
{
"mcpServers": {
"char-tools": {
"command": "npx",
"args": ["mcp-character-tools"]
}
}
}
All Tools Reference
See sample_outputs.md for complete examples with inputs and outputs for all 14+ tools.
| Tool | Description |
|---|---|
count_letter | Count a specific letter |
count_letters | Count multiple letters at once |
count_substring | Count substring occurrences |
letter_frequency | Get frequency distribution |
spell_word | Break into characters |
char_at | Get character at index |
nth_character | Get nth character (1-based) |
word_length | Get exact length |
reverse_text | Reverse text, detect palindromes |
compare_texts | Compare two texts |
analyze_sentence | Word-by-word breakdown |
batch_count | Count across multiple words |
get_tricky_words | List commonly miscounted words |
check_tricky_word | Check if word is tricky |
Development
# Install dependencies
npm install
# Build
npm run build
# Run tests
npm test
# Run tests with coverage
npm run test:coverage
# Development mode with auto-rebuild
npm run dev
Testing
The project includes comprehensive tests for all tools:
npm test
Test files:
tests/counting.test.ts- Counting tools teststests/spelling.test.ts- Spelling tools teststests/analysis.test.ts- Analysis tools teststests/tricky-words.test.ts- Tricky words resource teststests/visualization.test.ts- Visualization utility tests
License
MIT