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C# REPL

C# REPL is a cross-platform command-line REPL for the rapid experimentation and exploration of C#. It evaluates C# as you type, with IntelliSense, NuGet and project references, and rich object output.

Install it as a .NET global tool and run it:

dotnet tool install -g csharprepl
csharprepl

Documentation

• Installation: install, update, and PATH setup
• Evaluating Code: run code, multi-line input, detailed output
• References and Scripts: add NuGet, assembly, and project references; load .csx files
• Exploring Code: documentation, source navigation, IL and lowered C#
• Keyboard Shortcuts: full key binding reference
• AI Completions: AI code completion (OpenAI, Anthropic, Gemini, and more)
• Inspecting a Running Process: attach to another .NET app, evaluate code inside it, and replace live methods
• Configuring CSharpRepl: command-line options and the config file
• Themes and Colors: built-in themes and custom theme.json
• Integrations: Windows Terminal, VS Code, and shell aliases

At a glance

• Syntax highlighting and IntelliSense with documentation and overloads
• Automatic formatting of typed input
• Install NuGet packages and reference local projects, solutions, and assemblies
• Dump and explore objects with rich formatting
• Inspect a running .NET application, evaluate code against its live state, and replace live methods
• Navigate to source via Source Link
• IL disassembly and lowered C# decompilation (Debug and Release)
• AI code completion via OpenAI, Anthropic, Gemini, Grok, DeepSeek, Mistral/Codestral, or any OpenAI-compatible provider (bring your own API key)