[BUG] Swift LSP plugin not detected - 'No LSP server available for file type: .swift'

Description

The official Swift LSP plugin (swift-lsp@claude-plugins-official) is not working. All LSP operations return "No LSP server available for file type: .swift" despite the plugin being properly installed and enabled.

Environment

• macOS Version: Darwin 25.2.0
• Claude Code Version: Latest (as of 2024-12-20)
• sourcekit-lsp: Available at /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/sourcekit-lsp
• Swift Index: Successfully built (.build/debug/index/store/v5 exists)

Plugin Installation

The official swift-lsp@claude-plugins-official plugin was installed through Claude Code's official plugin installation flow and is enabled in settings:

Settings (.claude/settings.json)

{
  "enabledPlugins": {
    "swift-lsp@claude-plugins-official": true
  }
}

Additional Local Configuration Attempted

We also tried creating a local plugin with explicit LSP configuration at .claude/plugins/swift-lsp/ with a .lsp.json file pointing to sourcekit-lsp. This also had no effect.

Steps to Reproduce

1. Install swift-lsp@claude-plugins-official via the official plugin flow
2. Verify it's enabled in settings
3. Build a Swift package to generate the index (swift build)
4. Attempt any LSP operation on a .swift file:

• documentSymbol
• hover
• goToDefinition
• findReferences

Expected Behavior

LSP operations should return semantic information from sourcekit-lsp (symbols, type info, definitions, references).

Actual Behavior

All LSP operations return:

No LSP server available for file type: .swift

Investigation Notes

1. The sourcekit-lsp binary exists and is executable at the standard Xcode toolchain path
2. The Swift index is successfully built after running swift build
3. The official plugin is installed and enabled
4. Created additional local plugin with explicit .lsp.json configuration - no effect
5. Restarted Claude Code sessions - no effect

Questions

1. Is the official swift-lsp@claude-plugins-official plugin supposed to provide Swift LSP support?
2. Are there additional configuration steps required after installing the plugin?
3. Are there any logs or debug output that could help diagnose why the LSP server isn't being started?

Impact

Without LSP support, Claude Code cannot provide:

• Accurate "go to definition" for Swift symbols
• "Find all references" with semantic understanding
• Type information on hover
• Symbol outlines for Swift files

This reduces accuracy when navigating and refactoring Swift codebases.