feat: Add Svelte language server support

CHANGELOG.md

@@ -43,6 +43,7 @@ Status of the `main` branch. Changes prior to the next official version change w
 * Language Servers:
   - Fix: clangd capability checks now tolerate valid initialize response shape differences and invalidate cached C++ document symbols when clangd/compile commands context changes #1359                                                                                                                                                                                                            
   - Fix: `rename_symbol` for Vue files now correctly propagates edits to the TypeScript server, enabling cross-file renames in `.vue` files 
+  - Add Svelte language server support (Svelte 5 + SvelteKit via `svelte-language-server`; auto-installed via npx; supports `.svelte`, `.ts`, and `.js` files)
   - Fix: Lean4 stale cache — empty document symbol responses (returned before `lake build` completes) are no longer persisted, preventing symbols from being permanently hidden #1356
   - Add JSON language server support via `vscode-json-languageserver` (experimental) #1391
   - Fix: Elixir/Expert deadlock on startup — Expert's build pipeline requires a `textDocument/didOpen` notification to start; Serena now opens `mix.exs` immediately after `initialized` so Expert begins compiling instead of waiting indefinitely #1397

README.md

@@ -110,7 +110,7 @@ Serena incorporates a powerful abstraction layer for the integration of language
 The underlying language servers are typically open-source projects or at least freely available for use.
 
 When using Serena's language server backend, we provide **support for over 40 programming languages**, including
-AL, Ansible, Bash, C#, C/C++, Clojure, Crystal, Dart, Elixir, Elm, Erlang, Fortran, F#, GLSL, Go, Groovy, Haskell, Haxe, HLSL, Java, JavaScript, JSON, Julia, Kotlin, Lean 4, Lua, Luau, Markdown, MATLAB, mSL, Nix, OCaml, Perl, PHP, PowerShell, Python, R, Ruby, Rust, Scala, Solidity, Swift, TOML, TypeScript, WGSL, YAML, and Zig.
+AL, Ansible, Bash, C#, C/C++, Clojure, Crystal, Dart, Elixir, Elm, Erlang, Fortran, F#, GLSL, Go, Groovy, Haskell, Haxe, HLSL, Java, JavaScript, JSON, Julia, Kotlin, Lean 4, Lua, Luau, Markdown, MATLAB, mSL, Nix, OCaml, Perl, PHP, PowerShell, Python, R, Ruby, Rust, Scala, Solidity, Svelte, Swift, TOML, TypeScript, Vue, WGSL, YAML, and Zig.
 
 ### The Serena JetBrains Plugin
 

docs/01-about/020_programming-languages.md

@@ -112,6 +112,8 @@ Some languages require additional installations or setup steps, as noted.
   works best with a `foundry.toml` or `hardhat.config.js` in the project root)
 * **Swift**
 * **TypeScript**
+* **Svelte**
+  (Svelte 5 + SvelteKit; requires Node.js v18+ and npm; supports .svelte, .svelte.ts, and .svelte.js files including Svelte 5 runes)
 * **Vue**    
   (3.x with TypeScript; requires Node.js v18+ and npm; supports .vue Single File Components with monorepo detection)
 * **YAML**

docs/02-usage/050_configuration.md

@@ -834,6 +834,21 @@ Supported settings:
 Notes:
 - `typescript_version` and `typescript_language_server_version` are read from `ls_specific_settings.typescript`, not from `ls_specific_settings.vue`.
 
+#### Svelte
+
+Serena uses `svelte-language-server` for the `svelte` language key, together with a companion TypeScript language server and `typescript-svelte-plugin`.
+
+Supported settings:
+
+| Setting | Default | Description |
+|---|---|---|
+| `svelte_language_server_version` | `0.17.30` | Override the bundled `svelte-language-server` npm package version Serena installs. |
+| `typescript_svelte_plugin_version` | `0.3.51` | Override the bundled `typescript-svelte-plugin` npm package version Serena installs. |
+| `npm_registry` | `null` | Override the npm registry Serena uses for the managed install. If unset on `svelte`, Serena falls back to `ls_specific_settings.typescript.npm_registry`. |
+
+Notes:
+- `typescript_version` and `typescript_language_server_version` are read from `ls_specific_settings.typescript`, not from `ls_specific_settings.svelte`.
+
 #### YAML
 
 Serena uses `yaml-language-server` for the `yaml` language key.

docs/02-usage/070_security.md

@@ -147,6 +147,7 @@ Only the language servers listed below download or install additional dependenci
 - **Elm**: `@elm-tooling/elm-language-server`
 - **PHP (`intelephense`)**: `intelephense`
 - **Solidity**: `@nomicfoundation/solidity-language-server`
+- **Svelte**: `svelte-language-server` and `typescript-svelte-plugin`, plus `typescript` and `typescript-language-server`
 - **TypeScript**: `typescript` and `typescript-language-server`
 - **Vue**: `@vue/language-server`, plus `typescript` and `typescript-language-server`
 - **VTSLS**: `@vtsls/language-server`

pyproject.toml

@@ -308,6 +308,7 @@ markers = [
   "rust: language server running for Rust",
   "typescript: language server running for TypeScript",
   "vue: language server running for Vue (uses TypeScript LSP)",
+  "svelte: language server running for Svelte / SvelteKit (uses Svelte LSP + TypeScript LSP)",
   "php: language server running for PHP",
   "perl: language server running for Perl",
   "csharp: language server running for C#",

src/serena/resources/project.template.yml

@@ -11,8 +11,8 @@ project_name: "project_name"
 #   matlab              nix                 pascal              perl                php
 #   php_phpactor        powershell          python              python_jedi         r
 #   rego                ruby                ruby_solargraph     rust                scala
-#   swift               terraform           toml                typescript          typescript_vts
-#   vue                 yaml                zig
+#   svelte              swift               terraform           toml                typescript
+#   typescript_vts      vue                 yaml                zig
 #   (This list may be outdated. For the current list, see values of Language enum here:
 #   https://github.com/oraios/serena/blob/main/src/solidlsp/ls_config.py
 #   For some languages, there are alternative language servers, e.g. csharp_omnisharp, ruby_solargraph.)