diff --git a/.gitignore b/.gitignore
index cfdba840..6e605ca9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -65,6 +65,7 @@ oldreference/
 !/scripts/README.md
 !/scripts/codemod/README.md
 !/CONTRIBUTING.md
+!/build-guide.md
 # Bundled Agent Skills ship their SKILL.md / README.md as source of truth.
 # The Pi skills loader rejects entries whose frontmatter `name` diverges from
 # the parent directory; losing SKILL.md to the blanket *.md ignore meant a