csharp-lsp connects the C# language server to Claude Code, giving it code intelligence and diagnostics for cs files. The plugin only wires up the server; the server binary must be installed separately.
What it does
Where C# LSP runs and what it adds, from its documentation
Registers the csharp-ls language server (command: csharp-ls) via the marketplace lspServers entry
Maps file extensions to the language: .cs
Gives Claude Code code intelligence and diagnostics for C# projects
When to use it
Good fit
Working in a C# codebase where Claude Code should use real language-server analysis
Wanting diagnostics and navigation from csharp-ls without leaving Claude Code
Not for
Projects in other languages (it only maps the extensions listed)
Setups where you cannot install the csharp-ls binary on PATH
How to install C# LSP
You need: Claude Code; csharp-ls binary on PATH; .NET SDK 6.0 or later
Install the language server binary first (the plugin does not bundle it):
dotnet tool install --global csharp-ls
Or on macOS: brew install csharp-ls
Install the plugin: /plugin install csharp-lsp@claude-plugins-official
Permissions and security
What it can access
Launches the csharp-ls process locally and reads the project files it analyzes
Security notes from the maintainers
Marketplace README: make sure you trust a plugin before installing, updating, or using it
Review the source before granting an agent access to credentials or production systems. We document what the maintainers state; we do not audit code.
Limitations
Requires the language server to be installed separately; the plugin does not install it
