simple-claude-cli

A simple command-line interface for interacting with Claude AI models using the Anthropic API.

Overview

simple-claude-cli allows you to easily interact with Claude AI directly from your terminal. It uses the official Anthropic AI SDK to connect to Claude's API and stream responses in real-time.

Features

• Real-time streaming of Claude's responses
• Colored terminal output for better readability
• Simple, intuitive interface
• Uses Claude 3.5 Haiku by default
• Customizable system prompts and predefined personas
• Conversation history - maintains context throughout your session
• Multi-line input - easily input code blocks or longer prompts
• Configurable max tokens - control response length

Prerequisites

• Rust and Cargo installed
• An Anthropic API key (get one from Anthropic's website)

Installation

From crates.io

Install directly from crates.io:

cargo install simple-claude-cli

This will install the claude command in your PATH.

From Source

Clone the repository and build the project:

git clone https://github.com/katsuhirohonda/simple-claude-cli.git
cd simple-claude-cli
cargo build --release

The compiled binary will be available at target/release/claude.

Usage

1. Set your Anthropic API key as an environment variable:

export ANTHROPIC_API_KEY=your_api_key_here

2. Run the application:

claude

3. Enter your questions or prompts. For multi-line input:

   • Type each line followed by Enter
   • Add the termination marker /// on a new line to submit your full message
   • For code blocks or longer text, this allows proper formatting

4. Type exit, quit, or press Enter on an empty line to end the conversation.

Configuration

You can customize Claude's behavior using environment variables:

Change the Claude model

export CLAUDE_MODEL="claude-3-7-sonnet-20250219"

By default, the application uses claude-3-5-haiku-latest.

Set maximum response length

Control the maximum length of Claude's responses:

export CLAUDE_MAX_TOKENS=4000

By default, responses are limited to 1024 tokens.

Custom system prompts

You can set a custom system prompt:

export CLAUDE_SYSTEM_PROMPT="You are a cybersecurity expert focused on threat analysis."

Predefined personas

Choose from several predefined personas:

export CLAUDE_PERSONA="engineer"  # Software engineering expert

Available personas:

• engineer - Software engineering expert
• writer - Creative writer with excellent language skills
• scientist - Scientist with expertise in various fields
• teacher - Patient teacher who explains concepts clearly
• chef - Professional chef with culinary knowledge
• therapist - Compassionate therapist who listens carefully

You can also set a custom persona directly:

export CLAUDE_PERSONA="You are a financial advisor specializing in retirement planning."

Priority between CLAUDE_PERSONA and CLAUDE_SYSTEM_PROMPT

When configuring Claude's behavior:

• If only CLAUDE_SYSTEM_PROMPT is set, it will be used as the system prompt.
• If only CLAUDE_PERSONA is set, it will be used as the system prompt.
• If both CLAUDE_PERSONA and CLAUDE_SYSTEM_PROMPT are set, CLAUDE_PERSONA takes precedence and CLAUDE_SYSTEM_PROMPT is ignored.
• If neither is set, Claude will use the default "You are a helpful assistant." prompt.

For example, if you set:

export CLAUDE_SYSTEM_PROMPT="You are a cybersecurity expert."
export CLAUDE_PERSONA="engineer"

Claude will use "You are an excellent software engineer." as the system prompt, ignoring the cybersecurity expert setting.

Dependencies

• anthropic-ai-sdk: Official Anthropic AI SDK for Rust
• tokio: Asynchronous runtime for Rust
• tracing: Logging and diagnostics
• colored: Terminal text coloring

License

MIT License

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.