# Reference

> Look up every command, setting, file format and keyword.

These pages describe Optics 1.10.5 exactly as it behaves. Use them when you know what you want to do and need the precise name, flag, column or code.

If you're new to Optics, start with the [quickstart](https://optics-framework.org/docs/get-started/quickstart) and come back here when you need a detail.

- [Keywords](https://optics-framework.org/docs/reference/keywords/): Every step you can write in a module, with its parameters and defaults.
- [CLI](https://optics-framework.org/docs/reference/cli): Every `optics` command, its flags, what it writes and its exit codes.
- [config.yaml](https://optics-framework.org/docs/reference/config): Every setting in a project's config.yaml, with examples for each platform.
- [Project files](https://optics-framework.org/docs/reference/files): The CSV and YAML formats for test cases, modules, elements, error definitions and API calls.
- [Engines and extras](https://optics-framework.org/docs/reference/engines): The drivers, element sources, OCR, image and LLM engines, and how to install them.
- [MCP server](https://optics-framework.org/docs/reference/mcp): The tools and resources `optics mcp` gives your AI agent.
- [HTTP API](https://optics-framework.org/docs/reference/http-api): The endpoints `optics serve` exposes, with request and response shapes.
- [Error codes](https://optics-framework.org/docs/reference/errors): What each Optics error code means and how to fix it.