Lsp Setup

---
name: lsp-setup
description: 'Enable code intelligence (go-to-definition, find-references, hover, type info) for any programming language by installing and configuring an LSP server for Copilot CLI. Detects the OS, installs the right server, and generates the JSON configuration (user-level or repo-level). Use when you need deeper code understanding and no LSP server is configured, or when the user asks to set up, install, or configure an LSP server.'
---

# LSP Setup for GitHub Copilot CLI

**UTILITY SKILL** — installs and configures Language Server Protocol servers for Copilot CLI.
USE FOR: "setup LSP", "install language server", "configure LSP for Java", "add TypeScript LSP", "enable code intelligence", "I need go-to-definition", "find references not working", "need better code understanding"
DO NOT USE FOR: general coding tasks, IDE/editor LSP configuration, non-Copilot-CLI setups

## Workflow

1. **Ask the language** — use `ask_user` to ask which programming language(s) the user wants LSP support for
2. **Detect the OS** — run `uname -s` (or check for Windows via `$env:OS` / `%OS%`) to determine macOS, Linux, or Windows
3. **Look up the LSP server** — read `references/lsp-servers.md` for known servers, install commands, and config snippets
4. **Ask scope** — use `ask_user` to ask whether the config should be user-level (`~/.copilot/lsp-config.json`) or repo-level (`lsp.json` at the repo root or `.github/lsp.json`)
5. **Install the server** — run the appropriate install command for the detected OS
6. **Write the config** — merge the new server entry into the chosen config file (`~/.copilot/lsp-config.json` for user-level; `lsp.json` or `.github/lsp.json` for repo-level). If a repo-level config already exists, keep using that location; otherwise ask the user which repo-level location they prefer. Create the file if missing and preserve existing entries.
7. **Verify** — confirm the LSP binary is on `$PATH` and the config file is valid JSON

## Configuration Format

Copilot CLI reads LSP configuration from user-level or repo-level locations, and repo-level config takes precedence over user-level config:

- **User-level**: `~/.copilot/lsp-config.json`
- **Repo-level**: `lsp.json` (repo root) or `.github/lsp.json`

The JSON structure:

```json
{
  "lspServers": {
    "<server-key>": {
      "command": "<binary>",
      "args": ["--stdio"],
      "fileExtensions": {
        ".<ext>": "<languageId>",
        ".<ext2>": "<languageId>"
      }
    }
  }
}
```

### Key rules

- `command` is the binary name (must be on `$PATH`) or an absolute path.
- `args` almost always includes `"--stdio"` to use standard I/O transport.
- `fileExtensions` maps each file extension (with leading dot) to a [Language ID](https://code.visualstudio.com/docs/languages/identifiers#_known-language-identifiers).
- Multiple servers can coexist in `lspServers`.
- When merging into an existing file, **never overwrite** other server entries — only add or update the target language key.

## Behavior

- Always use `ask_user` with `choices` when asking the user to pick a language or scope.
- If the language is not listed in `references/lsp-servers.md`, search the web for "<language> LSP server" and guide the user through manual configuration.
- If a package manager is not available (e.g. no Homebrew on macOS), suggest alternative install methods from the reference file.
- After installation, run `which <binary>` (or `where.exe` on Windows) to confirm the binary is accessible.
- Show the user the final config JSON before writing it.
- If the config file already exists, read it first and merge — do not clobber.

## Verification

After setup, tell the user:

1. Type `/exit` to quit Copilot CLI — this is **required** so the new LSP configuration is loaded on next launch
2. Re-launch `copilot` in a project with files of the configured language
3. Run `/lsp` to check the server status
4. Try code intelligence features like go-to-definition or hover

# Known LSP Servers for Copilot CLI

Reference data for the `lsp-setup` skill. Each section contains install commands per OS and a ready-to-use config snippet.

> **Config snippet format**: Each snippet below shows the object to insert as a value under the top-level `lspServers` key. A complete config file looks like: `{ "lspServers": { <snippet here> } }`. When adding multiple languages, merge their snippets as sibling keys under `lspServers`.

---

## TypeScript / JavaScript

**Server**: [typescript-language-server](https://github.com/typescript-language-server/typescript-language-server)

### Install

| OS      | Command                                               |
|---------|-------------------------------------------------------|
| Any     | `npm install -g typescript typescript-language-server` |

### Config snippet

```json
{
  "typescript": {
    "command": "typescript-language-server",
    "args": ["--stdio"],
    "fileExtensions": {
      ".ts": "typescript",
      ".tsx": "typescriptreact",
      ".js": "javascript",
      ".jsx": "javascriptreact"
    }
  }
}
```

---

## Java

**Server**: [Eclipse JDT Language Server (jdtls)](https://github.com/eclipse-jdtls/eclipse.jdt.ls)

Requires **Java 21+** on `JAVA_HOME` or `$PATH`.

### Install

| OS      | Command                           |
|---------|-----------------------------------|
| macOS   | `brew install jdtls`              |
| Linux   | Check distro repos for `jdtls` or `eclipse.jdt.ls`; alternatively download from https://download.eclipse.org/jdtls/milestones/ |
| Windows | Download from https://download.eclipse.org/jdtls/milestones/ and add `bin/` to `PATH` |

On macOS with Homebrew, the binary is installed as `jdtls` on `$PATH`.

### Config snippet

```json
{
  "java": {
    "command": "jdtls",
    "args": [],
    "fileExtensions": {
      ".java": "java"
    }
  }
}
```

> **Note**: The `jdtls` wrapper script handles `--stdio` mode internally. If using a manual install, you may need to invoke the launcher jar directly — see the [jdtls README](https://github.com/eclipse-jdtls/eclipse.jdt.ls#running-from-command-line-with-wrapper-script) for details.

---

## Python

**Server**: [pyright](https://github.com/microsoft/pyright)

### Install

| OS      | Command                    |
|---------|----------------------------|
| Any     | `npm install -g pyright`   |
| Any     | `pip install pyright`      |

### Config snippet

```json
{
  "python": {
    "command": "pyright-langserver",
    "args": ["--stdio"],
    "fileExtensions": {
      ".py": "python"
    }
  }
}
```

---

## Go

**Server**: [gopls](https://github.com/golang/tools/tree/master/gopls)

### Install

| OS      | Command                                    |
|---------|--------------------------------------------|
| Any     | `go install golang.org/x/tools/gopls@latest` |
| macOS   | `brew install gopls`                       |

### Config snippet

```json
{
  "go": {
    "command": "gopls",
    "args": ["serve"],
    "fileExtensions": {
      ".go": "go"
    }
  }
}
```

---

## Rust

**Server**: [rust-analyzer](https://github.com/rust-lang/rust-analyzer)

### Install

| OS      | Command                        |
|---------|--------------------------------|
| Any     | `rustup component add rust-analyzer` |
| macOS   | `brew install rust-analyzer`   |
| Linux   | Distribution package or `rustup` |
| Windows | `rustup component add rust-analyzer` or download from GitHub releases |

### Config snippet

```json
{
  "rust": {
    "command": "rust-analyzer",
    "args": [],
    "fileExtensions": {
      ".rs": "rust"
    }
  }
}
```

---

## C / C++

**Server**: [clangd](https://clangd.llvm.org/)

### Install

| OS      | Command                                |
|---------|----------------------------------------|
| macOS   | `brew install llvm` (clangd included) or Xcode command line tools |
| Linux   | `apt install clangd` / `dnf install clang-tools-extra` |
| Windows | Download LLVM from https://releases.llvm.org/ |

### Config snippet

```json
{
  "cpp": {
    "command": "clangd",
    "args": ["--background-index"],
    "fileExtensions": {
      ".c": "c",
      ".h": "c",
      ".cpp": "cpp",
      ".cxx": "cpp",
      ".cc": "cpp",
      ".hpp": "cpp",
      ".hxx": "cpp"
    }
  }
}
```

---

## C# (.NET)

**Server**: [Roslyn Language Server](https://github.com/dotnet/roslyn) (via `dotnet dnx`)

### Install

| OS      | Command                                                        |
|---------|----------------------------------------------------------------|
| Any     | Requires the [.NET SDK](https://dot.net/download) installed    |

### Config snippet

```json
{
  "csharp": {
    "command": "dotnet",
    "args": ["dnx", "roslyn-language-server", "--yes", "--prerelease", "--", "--stdio", "--autoLoadProjects"],
    "fileExtensions": {
      ".cs": "csharp"
    }
  }
}
```

---

## Ruby

**Server**: [solargraph](https://github.com/castwide/solargraph)

### Install

| OS      | Command                   |
|---------|---------------------------|
| Any     | `gem install solargraph`  |

### Config snippet

```json
{
  "ruby": {
    "command": "solargraph",
    "args": ["stdio"],
    "fileExtensions": {
      ".rb": "ruby",
      ".rake": "ruby",
      ".gemspec": "ruby"
    }
  }
}
```

---

## PHP

**Server**: [intelephense](https://github.com/bmewburn/vscode-intelephense)

### Install

| OS      | Command                                    |
|---------|--------------------------------------------|
| Any     | `npm install -g intelephense`              |

### Config snippet

```json
{
  "php": {
    "command": "intelephense",
    "args": ["--stdio"],
    "fileExtensions": {
      ".php": "php"
    }
  }
}
```

---

## Kotlin

**Server**: [kotlin-language-server](https://github.com/fwcd/kotlin-language-server)

### Install

| OS      | Command                                           |
|---------|---------------------------------------------------|
| macOS   | `brew install kotlin-language-server`             |
| Any     | Download from GitHub releases and add to `PATH`   |

### Config snippet

```json
{
  "kotlin": {
    "command": "kotlin-language-server",
    "args": [],
    "fileExtensions": {
      ".kt": "kotlin",
      ".kts": "kotlin"
    }
  }
}
```

---

## Swift

**Server**: [sourcekit-lsp](https://github.com/swiftlang/sourcekit-lsp) (bundled with Swift toolchain)

### Install

| OS      | Command                                                        |
|---------|----------------------------------------------------------------|
| macOS   | Included with Xcode; binary at `xcrun sourcekit-lsp`          |
| Linux   | Included with Swift toolchain; install from https://swift.org  |

### Config snippet

```json
{
  "swift": {
    "command": "sourcekit-lsp",
    "args": [],
    "fileExtensions": {
      ".swift": "swift"
    }
  }
}
```

> On macOS you may need to use the full path: `/usr/bin/sourcekit-lsp` or set `command` to `xcrun` with `args: ["sourcekit-lsp"]`.

---

## Lua

**Server**: [lua-language-server](https://github.com/LuaLS/lua-language-server)

### Install

| OS      | Command                              |
|---------|--------------------------------------|
| macOS   | `brew install lua-language-server`   |
| Linux   | Download from GitHub releases        |
| Windows | Download from GitHub releases        |

### Config snippet

```json
{
  "lua": {
    "command": "lua-language-server",
    "args": [],
    "fileExtensions": {
      ".lua": "lua"
    }
  }
}
```

---

## YAML

**Server**: [yaml-language-server](https://github.com/redhat-developer/yaml-language-server)

### Install

| OS      | Command                                      |
|---------|----------------------------------------------|
| Any     | `npm install -g yaml-language-server`        |

### Config snippet

```json
{
  "yaml": {
    "command": "yaml-language-server",
    "args": ["--stdio"],
    "fileExtensions": {
      ".yaml": "yaml",
      ".yml": "yaml"
    }
  }
}
```

---

## Bash / Shell

**Server**: [bash-language-server](https://github.com/bash-lsp/bash-language-server)

### Install

| OS      | Command                                       |
|---------|-----------------------------------------------|
| Any     | `npm install -g bash-language-server`         |

### Config snippet

```json
{
  "bash": {
    "command": "bash-language-server",
    "args": ["start"],
    "fileExtensions": {
      ".sh": "shellscript",
      ".bash": "shellscript",
      ".zsh": "shellscript"
    }
  }
}
```