tc – Token Counter CLI for Claude

tc is a lightweight CLI tool that counts tokens in your input using Anthropic Claude models. Inspired by the classic Unix tool wc, but for LLM prompts.

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✨ Features

• 🔢 Counts tokens using Claude 3 models
• 📂 Supports both file input and stdin
• 🧱 Outputs only the token number (stdout)
• 📤 Prints errors to stderr
• 🎯 Supports multiple models via short aliases
• 🧑‍💻 Written in TypeScript

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🚀 Installation

Clone the repo and install dependencies:

git clone https://github.com/yourname/tc.git
cd tc
npm install

To make the command globally available:

npm link

You can now use tc anywhere in your terminal.

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🔐 Setup

You need an Anthropic API key. Create a .env file in the project root:

ANTHROPIC_API_KEY=your_api_key_here

Or export it:

export ANTHROPIC_API_KEY=your_api_key_here

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🧪 Usage

From a file

tc --file prompt.md

From stdin

cat prompt.md | tc

Specify model

tc --file prompt.md --model haiku
tc --model opus < input.txt

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🧠 Supported Model Aliases

Alias	Claude Model ID
sonnet	claude-3-7-sonnet-20250219
haiku	claude-3-haiku@20240307
opus	claude-3-opus@20240229
haiku35	claude-3-5-haiku@20241022
sonnet35	claude-3-5-sonnet@20240620
sonnet35v2	claude-3-5-sonnet-v2@20241022

Default model: sonnet

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📤 Output

Only the number of tokens is printed to stdout:

$ tc --file input.md
847

Errors and help messages go to stderr:

❌ Unknown model alias: snafu
   Available: sonnet, haiku, opus, sonnet35, haiku35, sonnet35v2

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📦 Development

Run with ts-node:

npx ts-node tc.ts --file input.md

Build:

npm run build
node dist/tc.js -f input.md

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🛠 License

ISC © BroJor

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💡 Inspiration

Built for developers who want to work closely with large language models and need precise token control. Inspired by wc, but LLM-native.