Lsp Setup

LSP Setup Skill

This skill guides you through installing and configuring LSP servers for GitHub Copilot CLI. It supports Linux and macOS and covers 5 language servers.

General Guidelines

OS Detection

Always detect the operating system first:

OS="$(uname -s)"

• Linux → use apt (Debian/Ubuntu) or check for other package managers
• Darwin → use brew

Path Conventions

• Never use hardcoded absolute paths like /home/username/...
• Always use $HOME for home directory references
• Resolve binary paths dynamically with command -v <binary> or which <binary>
• The LSP config file is located at $HOME/.copilot/lsp-config.json

Workflow

For each LSP server:

1. Check if it's already installed (command -v <binary>)
2. Install it using the appropriate method for the detected OS
3. Resolve the absolute path of the installed binary
4. Add an entry to $HOME/.copilot/lsp-config.json
5. Verify with /lsp show and /lsp test <name>

LSP Server: Go (gopls)

Prerequisites

• Go must be installed (go version)

Install

go install golang.org/x/tools/gopls@latest

Works identically on Linux and macOS. The binary is installed to $HOME/go/bin/gopls (or $GOPATH/bin/gopls if GOPATH is set).

Verify

GOPLS_PATH="$(command -v gopls || echo "$HOME/go/bin/gopls")"
"$GOPLS_PATH" version

lsp-config.json entry

"go": {
  "command": "<resolved absolute path to gopls>",
  "args": ["serve"],
  "fileExtensions": {
    ".go": "go"
  }
}

LSP Server: TypeScript/JavaScript (typescript-language-server)

Prerequisites

• Node.js must be installed (node --version)

Install

npm install -g typescript-language-server typescript

Works identically on Linux and macOS.

Verify

TSL_PATH="$(command -v typescript-language-server)"
"$TSL_PATH" --version

lsp-config.json entry

"typescript": {
  "command": "<resolved absolute path to typescript-language-server>",
  "args": ["--stdio"],
  "fileExtensions": {
    ".ts": "typescript",
    ".tsx": "typescriptreact",
    ".js": "javascript",
    ".jsx": "javascriptreact"
  }
}

LSP Server: Python (pylsp)

Prerequisites

• Python 3 must be installed (python3 --version)
• pip3 must be available (pip3 --version)

Install

Detect if --break-system-packages is needed (required on Debian/Ubuntu with PEP 668 externally-managed Python):

OS="$(uname -s)"
if [ "$OS" = "Linux" ] && python3 -c "import sysconfig; print(sysconfig.get_path('stdlib'))" 2>/dev/null | grep -q "/usr/lib"; then
  pip3 install --user --break-system-packages python-lsp-server
else
  pip3 install --user python-lsp-server
fi

On macOS with Homebrew Python, --user install works without --break-system-packages.

Verify

PYLSP_PATH="$(command -v pylsp || echo "$HOME/.local/bin/pylsp")"
"$PYLSP_PATH" --help

lsp-config.json entry

"python": {
  "command": "<resolved absolute path to pylsp>",
  "args": [],
  "fileExtensions": {
    ".py": "python"
  }
}

LSP Server: C/C++ (clangd)

Prerequisites

• None (installed via system package manager)

Install

OS="$(uname -s)"
if [ "$OS" = "Darwin" ]; then
  # clangd is included with Xcode Command Line Tools or can be installed via brew
  if ! command -v clangd &>/dev/null; then
    brew install llvm
    # clangd will be at $(brew --prefix llvm)/bin/clangd
  fi
elif [ "$OS" = "Linux" ]; then
  sudo apt install -y clangd
fi

Verify

CLANGD_PATH="$(command -v clangd)"
# On macOS with brew llvm, it may be at: $(brew --prefix llvm)/bin/clangd
if [ -z "$CLANGD_PATH" ] && [ "$(uname -s)" = "Darwin" ]; then
  CLANGD_PATH="$(brew --prefix llvm)/bin/clangd"
fi
"$CLANGD_PATH" --version

lsp-config.json entry

"cpp": {
  "command": "<resolved absolute path to clangd>",
  "args": [],
  "fileExtensions": {
    ".c": "c",
    ".h": "c",
    ".cpp": "cpp",
    ".hpp": "cpp",
    ".cc": "cpp",
    ".cxx": "cpp"
  }
}

LSP Server: Java (jdtls)

Prerequisites

• Java 21+ must be installed (java -version)

Install

1. Download the latest jdtls release:

JDTLS_VERSION="1.56.0"
JDTLS_BUILD="202601291528"
JDTLS_DIR="$HOME/.local/share/jdtls"
mkdir -p "$JDTLS_DIR"
curl -sL "https://www.eclipse.org/downloads/download.php?file=/jdtls/milestones/${JDTLS_VERSION}/jdt-language-server-${JDTLS_VERSION}-${JDTLS_BUILD}.tar.gz&r=1" \
  -o /tmp/jdtls.tar.gz -L
tar -xzf /tmp/jdtls.tar.gz -C "$JDTLS_DIR"
rm -f /tmp/jdtls.tar.gz

2. Create a cross-platform wrapper script:

mkdir -p "$HOME/.local/bin"
cat > "$HOME/.local/bin/jdtls" << 'WRAPPER'
#!/bin/sh
# Cross-platform JAVA_HOME detection
if [ -z "$JAVA_HOME" ]; then
  OS="$(uname -s)"
  if [ "$OS" = "Darwin" ]; then
    JAVA_HOME="$(/usr/libexec/java_home 2>/dev/null || true)"
  elif [ "$OS" = "Linux" ]; then
    JAVA_BIN="$(readlink -f "$(command -v java)" 2>/dev/null)"
    if [ -n "$JAVA_BIN" ]; then
      JAVA_HOME="$(dirname "$(dirname "$JAVA_BIN")")"
    fi
  fi
  export JAVA_HOME
fi
exec "$HOME/.local/share/jdtls/bin/jdtls" "$@"
WRAPPER
chmod +x "$HOME/.local/bin/jdtls"

Verify

"$HOME/.local/bin/jdtls" --help

lsp-config.json entry

"java": {
  "command": "<HOME>/.local/bin/jdtls",
  "args": [],
  "fileExtensions": {
    ".java": "java"
  }
}

Replace <HOME> with the resolved $HOME path.

Generating the Full lsp-config.json

After installing the desired LSP servers, generate or update $HOME/.copilot/lsp-config.json.

The final file should look like this (include only the servers that were installed):

{
  "lspServers": {
    "go": {
      "command": "<absolute path to gopls>",
      "args": ["serve"],
      "fileExtensions": { ".go": "go" }
    },
    "typescript": {
      "command": "<absolute path to typescript-language-server>",
      "args": ["--stdio"],
      "fileExtensions": {
        ".ts": "typescript",
        ".tsx": "typescriptreact",
        ".js": "javascript",
        ".jsx": "javascriptreact"
      }
    },
    "python": {
      "command": "<absolute path to pylsp>",
      "args": [],
      "fileExtensions": { ".py": "python" }
    },
    "cpp": {
      "command": "<absolute path to clangd>",
      "args": [],
      "fileExtensions": {
        ".c": "c", ".h": "c",
        ".cpp": "cpp", ".hpp": "cpp",
        ".cc": "cpp", ".cxx": "cpp"
      }
    },
    "java": {
      "command": "<absolute path to jdtls>",
      "args": [],
      "fileExtensions": { ".java": "java" }
    }
  }
}

Important: Always resolve paths dynamically using command -v or known install locations. Never hardcode user-specific paths.

Verification

After updating the config, instruct the user to run in Copilot CLI:

/lsp reload
/lsp show

To test a specific server:

/lsp test go
/lsp test typescript
/lsp test python
/lsp test cpp
/lsp test java

References

• Copilot CLI LSP docs
• gopls
• typescript-language-server
• python-lsp-server
• clangd
• Eclipse JDT.LS