Add lsp-setup skill for configuring LSP servers in Copilot CLI

docs/README.skills.md

@@ -178,6 +178,7 @@ See [CONTRIBUTING.md](../CONTRIBUTING.md#adding-skills) for guidelines on how to
 | [kotlin-mcp-server-generator](../skills/kotlin-mcp-server-generator/SKILL.md) | Generate a complete Kotlin MCP server project with proper structure, dependencies, and implementation using the official io.modelcontextprotocol:kotlin-sdk library. | None |
 | [kotlin-springboot](../skills/kotlin-springboot/SKILL.md) | Get best practices for developing applications with Spring Boot and Kotlin. | None |
 | [legacy-circuit-mockups](../skills/legacy-circuit-mockups/SKILL.md) | Generate breadboard circuit mockups and visual diagrams using HTML5 Canvas drawing techniques. Use when asked to create circuit layouts, visualize electronic component placements, draw breadboard diagrams, mockup 6502 builds, generate retro computer schematics, or design vintage electronics projects. Supports 555 timers, W65C02S microprocessors, 28C256 EEPROMs, W65C22 VIA chips, 7400-series logic gates, LEDs, resistors, capacitors, switches, buttons, crystals, and wires. | `references/28256-eeprom.md`<br />`references/555.md`<br />`references/6502.md`<br />`references/6522.md`<br />`references/6C62256.md`<br />`references/7400-series.md`<br />`references/assembly-compiler.md`<br />`references/assembly-language.md`<br />`references/basic-electronic-components.md`<br />`references/breadboard.md`<br />`references/common-breadboard-components.md`<br />`references/connecting-electronic-components.md`<br />`references/emulator-28256-eeprom.md`<br />`references/emulator-6502.md`<br />`references/emulator-6522.md`<br />`references/emulator-6C62256.md`<br />`references/emulator-lcd.md`<br />`references/lcd.md`<br />`references/minipro.md`<br />`references/t48eeprom-programmer.md` |
+| [lsp-setup](../skills/lsp-setup/SKILL.md) | Install and configure LSP servers for any programming language to work with GitHub Copilot CLI. Detects the OS, installs the right LSP server, and generates the LSP configuration (user-level or repo-level). Say "setup LSP" to start. | `references/lsp-servers.md` |
 | [make-repo-contribution](../skills/make-repo-contribution/SKILL.md) | All changes to code must follow the guidance documented in the repository. Before any issue is filed, branch is made, commits generated, or pull request (or PR) created, a search must be done to ensure the right steps are followed. Whenever asked to create an issue, commit messages, to push code, or create a PR, use this skill so everything is done correctly. | `assets/issue-template.md`<br />`assets/pr-template.md` |
 | [make-skill-template](../skills/make-skill-template/SKILL.md) | Create new Agent Skills for GitHub Copilot from prompts or by duplicating this template. Use when asked to "create a skill", "make a new skill", "scaffold a skill", or when building specialized AI capabilities with bundled resources. Generates SKILL.md files with proper frontmatter, directory structure, and optional scripts/references/assets folders. | None |
 | [markdown-to-html](../skills/markdown-to-html/SKILL.md) | Convert Markdown files to HTML similar to `marked.js`, `pandoc`, `gomarkdown/markdown`, or similar tools; or writing custom script to convert markdown to html and/or working on web template systems like `jekyll/jekyll`, `gohugoio/hugo`, or similar web templating systems that utilize markdown documents, converting them to html. Use when asked to "convert markdown to html", "transform md to html", "render markdown", "generate html from markdown", or when working with .md files and/or web a templating system that converts markdown to HTML output. Supports CLI and Node.js workflows with GFM, CommonMark, and standard Markdown flavors. | `references/basic-markdown-to-html.md`<br />`references/basic-markdown.md`<br />`references/code-blocks-to-html.md`<br />`references/code-blocks.md`<br />`references/collapsed-sections-to-html.md`<br />`references/collapsed-sections.md`<br />`references/gomarkdown.md`<br />`references/hugo.md`<br />`references/jekyll.md`<br />`references/marked.md`<br />`references/pandoc.md`<br />`references/tables-to-html.md`<br />`references/tables.md`<br />`references/writing-mathematical-expressions-to-html.md`<br />`references/writing-mathematical-expressions.md` |

skills/lsp-setup/SKILL.md

@@ -0,0 +1,69 @@
+---
+name: lsp-setup
+description: 'Install and configure LSP servers for any programming language to work with GitHub Copilot CLI. Detects the OS, installs the right LSP server, and generates the LSP configuration (user-level or repo-level). Say "setup LSP" to start.'
+---
+
+# 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"
+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 `$env:OS` / `%OS%`) to determine macOS, Linux, or Windows
+3. **Look up the LSP server** — read `references/lsp-servers.md` for known servers, install commands, and config snippets
+4. **Ask scope** — use `ask_user` to ask whether the config should be user-level (`~/.copilot/lsp-config.json`) or repo-level (`.github/lsp.json`)
+5. **Install the server** — run the appropriate install command for the detected OS
+6. **Write the config** — merge the new server entry into the chosen config file (`~/.copilot/lsp-config.json` for user-level, `.github/lsp.json` for repo-level); create it if missing, preserve existing entries
+7. **Verify** — confirm the LSP binary is on `$PATH` and the config file is valid JSON
+
+## Configuration Format
+
+Copilot CLI reads LSP configuration from two locations (repo-level takes precedence):
+
+- **User-level**: `~/.copilot/lsp-config.json`
+- **Repo-level**: `.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. Launch `copilot` in a project with files of the configured language
+2. Run `/lsp` to check the server status
+3. Try code intelligence features like go-to-definition or hover