diff --git a/tools/build-docs.js b/tools/build-docs.js
index dfb2c0a8e..878eeee8f 100644
--- a/tools/build-docs.js
+++ b/tools/build-docs.js
@@ -21,7 +21,7 @@ const archiver = require('archiver');
 const PROJECT_ROOT = path.dirname(__dirname);
 const BUILD_DIR = path.join(PROJECT_ROOT, 'build');
 
-const SITE_URL = process.env.SITE_URL || 'https://bmad-code-org.github.io/BMAD-METHOD';
+let SITE_URL; // Resolved in main() via shared getSiteUrl()
 const REPO_URL = 'https://github.com/bmad-code-org/BMAD-METHOD';
 
 // DO NOT CHANGE THESE VALUES!
@@ -53,6 +53,12 @@ const LLM_EXCLUDE_PATTERNS = [
  */
 
 async function main() {
+  // Resolve site URL using the same function as Astro config
+  const { pathToFileURL } = require('node:url');
+  const siteUrlModule = path.join(PROJECT_ROOT, 'website/src/lib/site-url.mjs');
+  const { getSiteUrl } = await import(pathToFileURL(siteUrlModule).href);
+  SITE_URL = getSiteUrl();
+
   console.log();
   printBanner('BMAD Documentation Build Pipeline');
   console.log();
diff --git a/website/astro.config.mjs b/website/astro.config.mjs
index 23a3179c4..d59de430a 100644
--- a/website/astro.config.mjs
+++ b/website/astro.config.mjs
@@ -4,7 +4,7 @@ import starlight from '@astrojs/starlight';
 import sitemap from '@astrojs/sitemap';
 import rehypeMarkdownLinks from './src/rehype-markdown-links.js';
 import rehypeBasePaths from './src/rehype-base-paths.js';
-import { getSiteUrl } from './src/lib/site-url.js';
+import { getSiteUrl } from './src/lib/site-url.mjs';
 
 const siteUrl = getSiteUrl();
 const urlParts = new URL(siteUrl);
diff --git a/website/src/components/Banner.astro b/website/src/components/Banner.astro
index f1e460705..218a017ee 100644
--- a/website/src/components/Banner.astro
+++ b/website/src/components/Banner.astro
@@ -1,5 +1,5 @@
 ---
-import { getSiteUrl } from '../lib/site-url.js';
+import { getSiteUrl } from '../lib/site-url.mjs';
 
 const SITE_URL = getSiteUrl();
 const fullDocsUrl = `${SITE_URL}/llms-full.txt`;
diff --git a/website/src/lib/site-url.js b/website/src/lib/site-url.mjs
similarity index 100%
rename from website/src/lib/site-url.js
rename to website/src/lib/site-url.mjs