[BUG] LSP plugins not loading servers on Windows - "No LSP server available for file type"

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?

Description

LSP plugins install successfully but language servers don't start on Windows. The LSP tool is available but always returns "No LSP server available for file type: .cs" (and other file types).

Environment

• OS: Windows 11
• Claude Code Version: Latest (December 2025)
• Plugin: omnisharp@claude-code-lsps from boostvolt/claude-code-lsps marketplace
• Language Server: csharp-ls v0.20.0 (installed via dotnet tool install -g csharp-ls)

Steps to Reproduce

1. Set environment variable: ENABLE_LSP_TOOL=1 (Machine level)
2. Add marketplace: /plugin marketplace add boostvolt/claude-code-lsps
3. Install plugin: /plugin install omnisharp@claude-code-lsps
4. Restart Claude Code
5. Try LSP operation: "Use LSP to list symbols in [any .cs file]"

Expected Behavior

LSP server should start and provide code intelligence (documentSymbol, goToDefinition, etc.)

Actual Behavior

• Plugin shows as installed (green dot in /plugin → Installed tab)
• csharp-ls binary is available in PATH and works manually
• LSP tool exists but returns: "No LSP server available for file type: .cs"

Investigation

• Verified .lsp.json config is correct (command: "csharp-ls")
• Bash is available on system (Git Bash + WSL)
• Hook script check-omnisharp.sh exists but may not execute properly on Windows
• Same issue occurs for JavaScript files (.js) with vtsls plugin

Possible Cause

The plugin hooks use bash scripts (.sh files) designed for macOS/Linux. Even with bash available on Windows, the LSP servers aren't being started. The plugin loading mechanism may not be properly initializing the language servers.

Workaround Attempted

None successful. The LSP feature appears non-functional on Windows with these plugins.

Additional Context

This was tested in both:

• Claude Code CLI (terminal)
• Claude Code VS Code extension

Both show the same behavior - plugin installed but servers not loading.

What Should Happen?

LSP plugins should properly initialize and start language servers on Windows when installed. After installing an LSP plugin like omnisharp@claude-code-lsps and setting ENABLE_LSP_TOOL=1, the LSP tool should be able to:

1. Detect and start the configured language server (e.g., csharp-ls) when working with supported file types
2. Provide code intelligence features (documentSymbol, goToDefinition, references, etc.)
3. Execute hook scripts (like check-omnisharp.sh) successfully on Windows, possibly by using native Windows equivalents or PowerShell scripts

The plugin loading mechanism should handle Windows-specific considerations for starting language servers, rather than only working on macOS/Linux systems.

Error Messages/Logs

No LSP server available for file type: .cs

Steps to Reproduce

1. Set environment variable: ENABLE_LSP_TOOL=1 (Machine level on Windows)
2. Add marketplace: /plugin marketplace add boostvolt/claude-code-lsps
3. Install plugin: /plugin install omnisharp@claude-code-lsps
4. Install the language server: dotnet tool install -g csharp-ls
5. Verify csharp-ls is in PATH: csharp-ls --version (should return v0.20.0 or similar)
6. Restart Claude Code completely
7. Open any C# project with .cs files
8. Ask Claude: "Use LSP to list symbols in Program.cs"
9. Observe the error: "No LSP server available for file type: .cs"

The same issue occurs with other LSP plugins (e.g., vtsls for JavaScript/TypeScript files).

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

Latest (December 2025)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_