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AIA User Manual

AIA ("AI Assistant") is a command-line program for working with large language models from your terminal. You keep your prompts as plain Markdown files, and AIA fills them in, sends them to the model of your choice, and gives you the answer, or keeps the conversation going in an interactive chat.

AIA

This manual covers AIA 2.0.0.

Who this manual is for

You use a terminal every day and you want an LLM to be part of that work, not a browser tab off to the side. You don't need to know Ruby to use AIA. Some optional features (ERB templates, custom tools) use Ruby, and the manual explains what you need when you get there.

What you can do with AIA

  • Keep a library of prompts. Each prompt is a .md file in your prompts directory (~/.prompts by default). You run one by name: aia code_review.
  • Fill in prompts with parameters. A prompt can declare values such as language or audience. AIA asks for them when you run it.
  • Feed it your files and your shell. Pass files on the command line, pipe text in on stdin, or embed $(git diff) in a prompt and AIA runs the command for you.
  • Chat. aia --chat opens an interactive session. Use / directives in the chat to switch models, include files, save checkpoints, and more.
  • Use any model. OpenAI, Anthropic, Google and the other providers RubyLLM supports, plus local models through Ollama or LM Studio. Pick one per run with --model.
  • Run several models at once. --model gpt-4o,claude-sonnet-4-5 sends the same prompt to both. Add --consensus and AIA combines their answers into one.
  • Chain prompts into pipelines. One prompt's output becomes the next one's input.
  • Give the model tools. Load Ruby tools or connect MCP servers so the model can read files, query APIs, or run commands, with your approval.
  • Track usage. --tokens and --cost show token counts, time and cost after every response.

A taste

# Ask a one-off question by piping it in
echo "Explain the difference between a process and a thread in two sentences." | aia

# Run a saved prompt against a file
aia summarize meeting_notes.txt

# Start a chat, with a role, on a specific model
aia --chat --role code_reviewer --model claude-sonnet-4-5

How this manual is organized

Part What it covers
Getting Started Installation, a Quick Tour of the main features, and Your First Prompt. Start here if you are new.
Everyday Use Running prompts, chat sessions, context files and piping, roles and skills, choosing models, and output, history and usage reports.
Writing Prompts Prompt files and front matter, parameters, directives, ERB and shell expansion, pipelines, and executable prompts.
Extending AIA Tools, MCP servers, multiple models and consensus, crews, local models, images and speech, and advanced modes.
Configuration The config file, environment variables, how settings override each other, and security.
Reference Every command-line option, every directive, every configuration key, and the FAQ and troubleshooting page.
Appendix Upgrading to 2.0, migrating old prompts, and a glossary.

The Getting Started and Everyday Use parts are written to be read in order. The rest you can dip into when you need it.

Getting help

Next steps