Skip to content

Configuring CSharpRepl

Jump to bottom
Will Fuqua edited this page Jun 29, 2026 · 4 revisions

Configuring C# REPL

C# REPL is configured with command-line options. The same options can be saved to a config file or a response file so they apply to every session.

Usage

csharprepl [OPTIONS] [@response-file.rsp] [script-file.csx] [-- <script-arguments>]
  • [OPTIONS]: any of the options below.
  • [@response-file.rsp]: a file of options, one per line.
  • [script-file.csx]: a C# script run before the prompt starts.
  • <script-arguments>: forwarded to the script and available in a global args variable.

Run csharprepl --help to see the options along with your installed frameworks and themes.

References and language

  • -r, --reference <dll>: reference an assembly, NuGet package, or csproj. Repeatable.
  • -u, --using <namespace>: add a using statement. Repeatable.
  • -f, --framework <framework>: reference a shared framework. Common values: Microsoft.NETCore.App (default), Microsoft.AspNetCore.App, Microsoft.WindowsDesktop.App.
  • --usePrereleaseNugets: consider prerelease versions when resolving the latest NuGet package.

Appearance

  • -t, --theme <theme.json>: syntax highlighting theme. See Themes and Colors.
  • --useTerminalPaletteTheme: use your terminal's palette instead of a theme file.
  • --prompt <markup>: set the prompt string.
  • --useUnicode: enable UTF-8 output and unicode decorations (needs terminal support).
  • --tabSize <width>: width of a tab character.
  • --culture <name>: culture used for MSDN documentation links. Defaults to the current culture.

Non-interactive evaluation

  • -e, --eval <code>: run code, print the result, and exit. Mutually exclusive with --eval-file.
  • --eval-file <path>: run a .csx or .cs file, print the result, and exit.
  • --streamPipedInput: when input is piped through stdin, evaluate it line by line instead of as one batch.

AI completions

See AI Completions for the provider list and setup.

  • --aiProvider <name>: provider preset (openai default, also anthropic, gemini, grok, deepseek, mistral, codestral).
  • --aiApiKey <key>: API key (overrides the provider's environment variable).
  • --aiEndpoint <url>: base URL of an OpenAI-compatible API (overrides the provider's default endpoint).
  • --aiModel <model>: model to use (overrides the provider's default).
  • --aiPrompt <prompt>: system prompt prefixed to every submission.
  • --aiHistoryCount <count>: number of previous REPL entries sent as context (default 5).

Key bindings

Each option is repeatable. See Keyboard Shortcuts for the defaults.

  • --triggerCompletionListKeys <binding>: open the completion list.
  • --newLineKeys <binding>: insert a newline.
  • --submitPromptKeys <binding>: submit the prompt.
  • --submitPromptDetailedKeys <binding>: submit with detailed output.

Diagnostics

  • --trace: write a trace file in the current directory, for bug reports.
  • -v, --version: print the version and exit.
  • -h, --help: print help and exit.

Connecting to a process

  • connect <pid>: connect to a running, connector-enabled process. The options above also apply to the remote session.
  • connect list: list the running, connector-enabled processes you can connect to.
  • connect init [--shell pwsh|powershell|cmd|bash|fish]: print the environment variables to launch your app with.

Once connected, the REPL gains the #replace, #wrap, #patches, and #revert commands for modifying live methods. See Connecting to a Running Process.

Config file

C# REPL reads a config file containing any of the options above, one per line. Run csharprepl --configure to open it in your editor (it reads the EDITOR environment variable).

Location:

  • Windows: C:\Users\<username>\AppData\Roaming\.csharprepl\config.rsp
  • Linux and macOS: ~/.config/.csharprepl/config.rsp

Tab completion

With dotnet-suggest enabled, options tab-complete, including --framework values and --using namespaces.

C# REPL

Using the REPL

Advanced

Clone this wiki locally