[BUG] C# LSP plugin from official marketplace not exposing LSP tool (Windows, v2.1.62)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

The csharp-lsp plugin from the official Anthropic marketplace (claude-plugins-official) installs successfully and shows as enabled. The csharp-ls binary is installed globally via dotnet tool install --global csharp-ls, is in PATH, and runs correctly (starts and awaits stdio input as expected).

However, no LSP tool is registered or exposed to the model. The model has no LSP-related tools in its toolset and cannot invoke any language server operations (diagnostics, go-to-definition, hover, etc.).

This appears to be the same regression described in #27498 (LSP tool no longer registered as callable tool), now confirmed on Windows with the official marketplace csharp-lsp plugin.

Related issues: #15914, #16360, #27498

What Should Happen?

When the csharp-lsp plugin is installed and csharp-ls is available in PATH, the LSP tool should be registered in the model's toolset, enabling language server operations on .cs files.

Steps to Reproduce

1. Install csharp-ls globally: dotnet tool install --global csharp-ls
2. Verify it is in PATH: csharp-ls starts and awaits stdio input
3. Install the official plugin: /plugins → Official marketplace → csharp-lsp
4. Restart Claude Code
5. Open a project with a .sln file in the working directory
6. Ask the model to use LSP for any C# file
7. Model reports no LSP tools are available in its toolset

Error Messages/Logs

No explicit error messages. The LSP tool simply does not appear in the model's available tools.
The csharp-ls binary works correctly when invoked manually.
Plugin shows as installed in the plugin manager.

Is this a regression?

Yes, this worked in a previous version (based on reports in #27498, LSP tool registration broke around v2.1.50).

Claude Code Version

2.1.62 (Claude Code)

Platform

Anthropic API

Operating System

Windows 11

Terminal/Shell

Git Bash (via Windows Terminal)

Additional Information

• Plugin config in the official marketplace manifest correctly defines lspServers with command: "csharp-ls" and extensionToLanguage: { ".cs": "csharp" }
• The csharp-ls binary is located at ~/.dotnet/tools/csharp-ls and is accessible in PATH
• The project contains a .sln solution file at the workspace root
• The model confirms it has no LSP-related tools exposed in its toolset