[BUG] LSP plugins not recognized on Windows 11 - "No LSP server available for file type: .rs"

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?

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet (found #14803 for macOS, this is Windows-specific)

What's Wrong?

LSP plugin for Rust (rust-analyzer-lsp) is not recognized by Claude Code on Windows 11. The LSP tool returns "No LSP server available for file type: .rs" despite:

1. Plugin installed and enabled via /plugins
2. ENABLE_LSP_TOOLS=1 environment variable set before launching Claude Code
3. rust-analyzer binary installed via rustup and available in PATH
4. rust-analyzer working correctly on the project (verified with rust-analyzer analysis-stats .)
5. Multiple Claude Code restarts after configuration

This appears to be the same fundamental issue as #14803 (macOS) but on Windows 11.

Error Messages/Logs

> find references to println!() using LSP

● LSP(operation: "findReferences", symbol: "println!", in: "src\main.rs")
  ⎿  No LSP server available for file type: .rs

No LSP-specific logs found. No feedback about LSP server startup success/failure.

What Should Happen?

When the rust-analyzer-lsp plugin is correctly installed and enabled:

1. Claude Code should start rust-analyzer on startup
2. The LSP tool should recognize .rs files and provide code intelligence
3. Operations like findReferences, goToDefinition, hover should work

Error Messages/Logs

LSP(operation: "findReferences", symbol: "println!", in: "src\main.rs")
  ⎿  No LSP server available for file type: .rs

Steps to Reproduce

Steps to Reproduce

1. System Info

• Claude Code version: 2.0.76
• Windows 11 Pro (Build 26100.2605)
• PowerShell 7.5.0
• rust-analyzer: 1.92.0 (installed via rustup component add rust-analyzer)

2. Verify rust-analyzer is working

PS> rust-analyzer --version
rust-analyzer 1.92.0 (ded5c06c 2025-12-08)

PS> rust-analyzer analysis-stats . 2>&1 | Select-Object -First 5
Database loaded:     745.25ms, 41mb (metadata 412.60ms, 560kb; build 51.15ms, 136kb)
  item trees: 1
  dependency lines of code: 938_432, item trees: 1_991
  dependency item stats: traits: 712, impl: 7_425, mods: 2_175, macro calls: 3_912, macro rules: 878
Item Tree Collection: 2.06s, 323mb

3. Set environment variable and launch Claude Code

PS> $env:ENABLE_LSP_TOOLS = "1"
PS> ls env: | Select-String "ENABLE"
ENABLE_LSP_TOOLS               1

PS> claude

4. Install and enable the plugin

/plugins discover
# Select rust-analyzer-lsp from claude-plugins-official
# Install with scope: user

5. Verify plugin status

/plugins installed

rust-analyzer-lsp @ claude-plugins-official
Scope: user
Version: 1.0.0
Rust language server for code intelligence and analysis
Author: Anthropic
Status: Enabled

6. Verify settings.json

PS> Get-Content "$env:USERPROFILE\.claude\settings.json"
{
  "enabledPlugins": {
    "rust-analyzer-lsp@claude-plugins-official": true
  }
}

7. Check plugin cache structure

PS> Get-ChildItem "$env:USERPROFILE\.claude\plugins\cache\claude-plugins-official\rust-analyzer-lsp" -Recurse

    Directory: C:\Users\phili\.claude\plugins\cache\claude-plugins-official\rust-analyzer-lsp

Mode                 LastWriteTime         Length Name
----                 -------------         ------ ----
d----          02/01/2026    17:57                1.0.0

    Directory: ...\rust-analyzer-lsp\1.0.0

Mode                 LastWriteTime         Length Name
----                 -------------         ------ ----
-a---          19/12/2025    10:31            735 README.md

Note: The plugin cache only contains a README.md file. There is no .lsp.json or .claude-plugin/plugin.json configuration file, unlike other plugin types.

8. Test project structure

C:.
│   Cargo.lock
│   Cargo.toml
│
└───src
        main.rs

// src/main.rs
fn main() {
    println!("Hello, world!");
}

9. Test LSP in Claude Code

> find references to println!() using LSP

● LSP(operation: "findReferences", symbol: "println!", in: "src\main.rs")
  ⎿  No LSP server available for file type: .rs

Claude Model

claude-sonnet-4-5-20250929

Is this a regression?

I don't know

Last Working Version

N/A - Never worked on Windows

Claude Code Version

2.0.76

Platform

Anthropic Console (OAuth)

Operating System

Windows 11 Pro (Build 26100.2605)

Terminal/Shell

PowerShell 7.5.0

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.0.76 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Observations

1. The LSP plugin in the marketplace (rust-analyzer-lsp@claude-plugins-official) only contains a README.md with installation instructions for rust-analyzer itself. There is no .lsp.json configuration file that would tell Claude Code how to start the language server.

1. Unlike external plugins (asana, github, etc.) which have a .claude-plugin/plugin.json file, the LSP plugins appear to be "built-in" with no actual configuration.

1. The /lsp command does not exist in Claude Code to check LSP server status.

1. /doctor shows no information about LSP status:

Diagnostics
└ Currently running: npm-global (2.0.76)
└ Path: C:\Program Files\nodejs\node.exe
└ Config install method: global
└ Auto-updates: enabled
└ Update permissions: Yes
└ Search: OK (vendor)

1. No LSP-specific logs are generated in ~/.claude/logs/ (directory is empty).

Related Issues

• #14803 - Same issue reported on macOS

Community Workaround

The community has developed a workaround via [Piebald-AI/claude-code-lsps](https://github.com/Piebald-AI/claude-code-lsps) which requires patching Claude Code using npx tweakcc --apply. This suggests the native LSP plugin loading mechanism has unresolved issues across all platforms.

Requested Fix

1. Include proper .lsp.json configuration in LSP plugins from the official marketplace
2. Add logging/feedback when LSP servers start or fail to start
3. Add /lsp status command to show configured servers and their status
4. Document the correct plugin structure for LSP servers on Windows
5. Add LSP status to /doctor output