diff --git a/package.json b/package.json
index b699a88..e40e49a 100644
--- a/package.json
+++ b/package.json
@@ -256,6 +256,11 @@
             "default": true,
             "description": "If false, do not update Luau-LSP and Selene configurations unless the Force Language Update is done"
           },
+          "slVscodeEdit.syntax.useGitHubDefinitions": {
+            "type": "boolean",
+            "default": true,
+            "description": "Fetch LSL definition files from GitHub instead of the Second Life viewer"
+          },
           "slVscodeEdit.ui.statusTimeoutSeconds": {
             "type": "number",
             "default": 3,
diff --git a/src/interfaces/configinterface.ts b/src/interfaces/configinterface.ts
index afea4b6..7293d29 100644
--- a/src/interfaces/configinterface.ts
+++ b/src/interfaces/configinterface.ts
@@ -30,6 +30,7 @@ export enum ConfigKey {
   PreprocessorConstantsInSLua = 'preprocessor.constantsInSLua',
   PreprocessorLSLSwitchStatements = 'preprocessor.lsl.switchStatements',
   LastSyntaxID = 'syntax.lastID',
+  UseGitHubDefinitions = 'syntax.useGitHubDefinitions',
   AskIfViewerScriptMismatchesMaster = 'sync.askIfViewerScriptMismatchesMaster',
   CompareHashBeforeSync = 'sync.compareHashBeforeSync',
   KeepViewerFileOpen = 'sync.keepViewerFileOpen',
diff --git a/src/shared/languagerepository.ts b/src/shared/languagerepository.ts
index 1861a4d..53a381b 100644
--- a/src/shared/languagerepository.ts
+++ b/src/shared/languagerepository.ts
@@ -10,6 +10,8 @@ import { LSLKeywords } from "./lslkeywords";
 import { LuaTypeDefinitions } from "./luadefsinterface";
 import { sortObjectKeysRecursive } from '../utils';
 
+const GitHubRawBase = "https://raw.githubusercontent.com/secondlife/lsl-definitions/main/generated";
+
 export interface LanguageInfo {
     id: string;
     lsl?: LSLKeywords;
@@ -156,6 +158,21 @@ export class LanguageRepository {
         }
     }
 
+    public async fetchFromGitHub(filename: string): Promise<string | null> {
+        const url = `${GitHubRawBase}/${filename}`;
+        try {
+            const response = await fetch(url);
+            if (!response.ok) {
+                console.warn(`GitHub fetch failed for ${filename}: HTTP ${response.status}`);
+                return null;
+            }
+            return await response.text();
+        } catch (error) {
+            console.error(`Error fetching ${filename} from GitHub:`, error);
+            return null;
+        }
+    }
+
     private async requestLanguageSyntax(socket: JSONRPCInterface, kind: string): Promise<any | null> {
         const params = { kind };
         try {
diff --git a/src/shared/languageservice.ts b/src/shared/languageservice.ts
index 7430e53..567d2a8 100644
--- a/src/shared/languageservice.ts
+++ b/src/shared/languageservice.ts
@@ -112,10 +112,20 @@ export class LanguageService implements DisposableLike {
         force?: boolean,
         syntaxCacheSupported?: boolean,
     ): Promise<boolean> {
+        // Try GitHub first if enabled (most reliable, no viewer dependency)
+        if (this.host.config.getConfig(ConfigKey.UseGitHubDefinitions, true)) {
+            const githubOk = await this.configureSyntaxFromGitHub(syntaxId);
+            if (githubOk) {
+                return true;
+            }
+        }
+
+        // Fallback to viewer cache if available
         if (syntaxCacheSupported && socket) {
             return await this.configureSyntaxFromViewerCache(syntaxId, socket);
         }
 
+        // Last resort: fetch from viewer and generate locally
         const syntax = await this.repository.getSyntax(syntaxId, {
             force,
             socket,
@@ -146,6 +156,30 @@ export class LanguageService implements DisposableLike {
         return true;
     }
 
+    private async configureSyntaxFromGitHub(syntaxId: string): Promise<boolean> {
+        const selene = new SelenePlugin(this.host);
+        const seleneYml = await this.repository.fetchFromGitHub("secondlife_selene.yml");
+        if (typeof seleneYml === "string") {
+            await selene.configureFromViewerCache(syntaxId, seleneYml);
+        } else {
+            console.warn("github_fetch: secondlife_selene.yml missing or invalid, skipping Selene configuration");
+        }
+
+        const luauLSP = new LuaLSPPlugin(this.host);
+        const dLuau = await this.repository.fetchFromGitHub("secondlife.d.luau");
+        const docs = await this.repository.fetchFromGitHub("secondlife.docs.json");
+        if (typeof dLuau === "string" && typeof docs === "string") {
+            await luauLSP.configureFromViewerCache(syntaxId, dLuau, docs);
+        } else {
+            console.warn("github_fetch: secondlife.d.luau or secondlife.docs.json missing or invalid, skipping Luau-LSP configuration");
+            return false;
+        }
+
+        this.languageVersion = syntaxId;
+        await ConfigService.getInstance().setConfig<string>(ConfigKey.LastSyntaxID, syntaxId, { target: "global" });
+        return true;
+    }
+
     private async configureSyntaxFromViewerCache(
         syntaxId: string,
         socket: JSONRPCInterface,