Lsp Setup

LSP setup for GitHub Copilot CLI

Detect the target programming language, operating system, server package, and configuration scope; install the correct LSP binary; then merge a valid lspServers JSON entry for GitHub Copilot CLI.

When to invoke

• "Set up LSP for this repository."
• "Install a language server for Java."
• "Configure TypeScript LSP for GitHub Copilot CLI."
• "Go-to-definition and find references are not working."
• "Help me make /lsp show a running server."

Prerequisites and context

• This skill is for GitHub Copilot CLI LSP configuration, not editor or IDE LSP settings.
• Read references/lsp-servers.md for known server binaries, install commands, and config snippets.
• The final language server command must be on $PATH or use an absolute path.
• In interactive environments that expose ask_user, use ask_user with choices for language and scope selection; in non-interactive environments, infer safely from repository files and document the assumption.

Procedure

1. Determine the language from user input or repository files.
2. Detect the OS with uname -s, or Windows indicators such as $env:OS / %OS%.
3. Read references/lsp-servers.md and select the known LSP server, install command, binary, arguments, extensions, and language IDs.
4. Choose configuration scope: user-level ~/.copilot/lsp-config.json, repo-level lsp.json, or repo-level .github/lsp.json.
5. If a repo-level config already exists, keep that location; otherwise choose the requested location or document the inferred one.
6. Install the server with the appropriate package manager or manual instruction.
7. Read existing config first, merge only the target server entry, and preserve all other lspServers entries.
8. Validate the JSON and verify the binary with which <binary> or where.exe <binary>.
9. Tell the user to /exit, restart copilot, run /lsp, and try hover, go-to-definition, or find-references.

Scope exclusions

This is a UTILITY SKILL for GitHub Copilot CLI only; do not use it for IDE/editor configuration. Most server entries use the literal argument "--stdio"; verify binaries with which <binary> on Unix-like systems and where.exe <binary> on Windows; the Windows command name is where.exe.

Configuration locations

Configuration format

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

Server selection and fallback

Gotchas

• Restart is required: after writing LSP config, the user must type /exit and relaunch copilot before the server is loaded.
• Repo-level config wins: lsp.json or .github/lsp.json takes precedence over ~/.copilot/lsp-config.json.
• Do not overwrite config: merge into lspServers; preserve existing entries and formatting as much as possible.
• Language IDs are not arbitrary: use known identifiers from the VS Code language identifier list.

Progressive disclosure and bundled resources

Output template

## LSP setup result — <language>

**Status:** configured | partially configured | blocked
**Scope:** user-level | repo-level root | repo-level .github
**Config file:** `<~/.copilot/lsp-config.json | lsp.json | .github/lsp.json>`
**Server key:** `<server-key>`
**Command:** `<binary>`

### Verification
- OS detected: `<uname -s | Windows>`
- Binary check: `which <binary>` or `where.exe <binary>` -> pass | fail
- JSON valid: pass | fail
- Existing entries preserved: yes | no

### Next user steps
1. Type `/exit` to quit GitHub Copilot CLI.
2. Relaunch `copilot` in a project with `<language>` files.
3. Run `/lsp` to check server status.
4. Try go-to-definition, find-references, hover, or type info.

Quality gate

• The target language and OS were identified or explicitly assumed.
• references/lsp-servers.md was read before selecting a known server.
• Config scope was chosen among ~/.copilot/lsp-config.json, lsp.json, and .github/lsp.json.
• Existing config was read and merged without overwriting unrelated lspServers entries.
• command, args, and fileExtensions are valid for the selected server.
• Binary availability was checked with which <binary> or where.exe <binary>.
• The final response tells the user to /exit, relaunch copilot, run /lsp, and test code intelligence.

References

• VS Code known language identifiers