Add Learn documentation source

learndocs-archive/docs-conceptual/AIShell/concepts/what-is-a-command-shell.md

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+---
+title: What is a command shell?
+ms.date: 01/12/2026
+description: Learn what a command shell is and how it works.
+ms.collection: ce-skilling-ai-copilot
+---
+# What is a command shell?
+
+[!INCLUDE[aishell-deprecated](../../../includes/aishell-deprecated.md)]
+
+A command shell is a text-based interface for interacting with a computer, also known as a
+Read-Eval-Print Loop ([REPL][15]).
+
+A shell takes input from the keyboard, evaluates that input, and executes the input as a shell
+command or gives the input to the operating system to be executed. Most shells can also read
+commands from a script file, and may include programming features like variables, flow control, and
+functions.
+
+## Terminals
+
+A terminal is an application that provides a text-based interface for hosting command shells. Some
+terminals are designed to work with a specific shell, while others can host multiple shells. They
+may also include advanced features such as:
+
+- Ability to create multiple panes within a single window
+- Ability to create multiple tabs to host multiple shells
+- Ability to change color schemes and fonts
+- Support for copy and paste operations
+
+The following list contains some examples of terminal applications:
+
+- [Windows Terminal][11] - a modern terminal application for Windows that can host multiple shells.
+- [Windows Console Host][10] - the default host application on Windows for text-based applications.
+  It can also host the Windows Command Shell or PowerShell.
+- [Terminal for macOS][14] - the default terminal application on macOS that can host the bash or zsh
+  shell.
+- [iTerm2 for macOS][12] - a popular 3rd-party terminal application for macOS.
+- [Azure Cloud Shell][02] - a browser-based terminal application that's hosted in Microsoft Azure.
+  Azure Cloud shell gives you the choice of using bash or PowerShell and come preconfigured with
+  many command-line tools to manage Azure resources.
+
+## General purpose command shells
+
+General purpose command shells are designed to work with the operating system. These shell allow you
+to run any command that the operating system supports. They also include shell-specific commands and
+programming features. The following list contains some examples of general purpose command shells:
+
+- [PowerShell][05]
+- [Windows Command Shell][07]
+- [bash][16] - popular on Linux
+- [zsh][13] - popular on macOS
+
+## Utility command shells
+
+Utility command shells are designed to work with specific applications or services. These shells can
+only run commands that are specific to the application or service. Some utility shells support
+running commands from a script file, but they don't include programming features. Usually, these
+shells can only be used interactively.
+
+- [AI Shell][01] - An interactive-only shell used to communicate with AI services such as Azure
+  OpenAI.
+- [netsh][08] - Network shell (netsh) is a command-line utility that allows you to configure and
+  display the status of various network components on Windows. It is both a command-line tool and a
+  command shell. It also supports running commands from a script file.
+
+## Command-line tools
+
+A command-line tool is a standalone program that's run from a command shell. Command-line tools are
+typically designed to perform a specific task, such as managing files, configuring settings, or
+querying for information. Command-line tools can be used in any shell that supports running external
+programs.
+
+- [Azure CLI][03] - a collection of command-line tools for managing Azure resources that can be run
+  in any supported shell.
+- [Azure PowerShell][04] - a collection of PowerShell modules for managing Azure resources that can
+  be run in any supported version of PowerShell.
+- [OpenSSH for Windows][06] - a command-line client, as well as a server, for secure communication
+  over a network.
+- [Windows Commands][09] - a collection of command-line tools that are built into Windows.
+
+In general, command-line tools don't provide a command shell (REPL) interface. The `netsh` command
+in Windows is an exception, as it's both a command-line tool and an interactive command shell.
+
+<!-- link references -->
+[01]: ../overview.md
+[02]: /azure/cloud-shell/overview
+[03]: /cli/azure
+[04]: /powershell/azure
+[05]: /powershell/scripting/overview
+[06]: /windows-server/administration/openssh/openssh-overview
+[07]: /windows-server/administration/windows-commands/cmd
+[08]: /windows-server/administration/windows-commands/netsh
+[09]: /windows-server/administration/windows-commands/windows-commands
+[10]: /windows/console/consoles
+[11]: /windows/terminal
+[12]: https://iterm2.com/
+[13]: https://support.apple.com/102360
+[14]: https://support.apple.com/guide/terminal/welcome/mac
+[15]: https://wikipedia.org/wiki/Read%E2%80%93eval%E2%80%93print_loop
+[16]: https://www.gnu.org/software/bash/

learndocs-archive/docs-conceptual/AIShell/developer/agent-architecture.md

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+---
+title: Architecture of AI Shell
+description: This article explains the architecture of AI Shell and API required to support agents.
+ms.date: 01/12/2026
+ms.topic: concept-article
+ms.collection: ce-skilling-ai-copilot
+---
+# AI Shell architecture
+
+[!INCLUDE[aishell-deprecated](../../../includes/aishell-deprecated.md)]
+
+![AI Shell architecture diagram.][01]
+
+## AIShell.Abstraction
+
+This project will be released as a NuGet package. It contains all the interfaces for defining an
+agent plugin that interacts with AI Shell.
+
+This abstraction layer includes:
+
+- `IShell`: Represents a proxy of the AI shell.
+- `IHost`: Represents a proxy of the shell host.
+- `IRenderElement`: Represents the `header/value` or `label/value` pairs for rendering objects in
+  table or list format.
+- `IStreamRender`: Represents a special render for rendering streaming response.
+- `ILLMAgent`: Represents an agent plugin.
+- `IOrchestrator`: Derives `ILLMAgent`. Represents a special agent that can route a query to the
+  most suitable agent.
+- `ICodeAnalyzer`: Derives `ILLMAgent`. Represents a special agent that can analyze code for
+  security concerns.
+- `CommandBase`: represents a command that an agent can register to the shell when being loaded.
+
+The most important interface method in `ILLMAgent` is `Task<bool> Chat(string input, IShell shell)`,
+which will be called by the shell when a query comes from the user. It gives extreme flexibility to
+the implementation of an agent. An agent can do whatever it wants targeting an arbitrary AI backend
+and render the output using the utilities provided by `IShell`.
+
+An agent plugin is responsible for managing its own chat history.
+
+## AIShell.Kernel
+
+This is the implementation of AI Shell. It consists of the following components:
+
+- ReadLine
+- Renders (markdown render, stream render, paging render)
+- Plugin management
+- Host (a range of utility methods for writing output and interactive prompting)
+- Command runner and built-in commands
+- Utilities (clipboard, tab completion, predictive intellisense)
+  - Code execution for `python`, `powershell`, `cmd`, and `bash` (to enable agents to do function
+    calling with LLM. **not-yet-started**)
+- Shell integration (deep integration with the command-line shell. **not-yet-started**)
+- Configuration (colors, key bindings, and etc. **not-yet-started**)
+
+## AIShell.App
+
+This is a thin wrapper over `AIShell.Kernel` to create an executable. The initial idea is to
+make `AIShell.Kernel` a library, so it can be used or hosted by other applications. We can
+easily merge `AIShell.App` into `AIShell.Kernel` if this idea no longer make sense.
+
+<!-- link references -->
+[01]: media/agent-architecture/aishell-agent-architecture.png
+