diff --git a/toolchain/builder/zeta-makepkg b/toolchain/builder/zeta-makepkg
index 95242be..fa15e36 100755
--- a/toolchain/builder/zeta-makepkg
+++ b/toolchain/builder/zeta-makepkg
@@ -69,6 +69,8 @@ Commands:
 Flags:
   --output <dir>     Output repository root (default: .)
                      Creates packages/<name>/ with tarball + package.lua
+  --repo <url>       Base URL for generated package.lua manifests
+                     (default: https://raw.githubusercontent.com/gretagen/...)
   -j, --jobs <N>    Number of parallel build jobs (default: nproc)
   --no-index         Don't update packages/index.lua after building
   --keep-work        Don't remove the build work directory
@@ -99,6 +101,7 @@ local function parse_cli(args)
     help      = false,
     recipe    = nil,
     jobs      = nil,  -- nil = auto-detect (nproc)
+    repo      = "https://raw.githubusercontent.com/gretagen/zeta-packages/refs/heads/main",
   }
 
   local i = 1
@@ -115,6 +118,13 @@ local function parse_cli(args)
         return nil
       end
       opts.output = args[i]
+    elseif a == "--repo" then
+      i = i + 1
+      if i > #args then
+        io.stderr:write("error: --repo requires a URL argument\n")
+        return nil
+      end
+      opts.repo = args[i]
     elseif a == "--no-index" then
       opts.no_index = true
     elseif a == "--keep-work" then
@@ -216,7 +226,7 @@ local function run_build(recipe_path, opts)
   local tarball_sha256 = packager.create_tarball(stage_dir, tarball_path)
 
   -- 10. Write package.lua manifest
-  packager.write_manifest(r, tarball_sha256, pkg_dir)
+  packager.write_manifest(r, tarball_sha256, pkg_dir, opts.repo)
 
   -- 11. Update index
   if not opts.no_index then
diff --git a/toolchain/lib/packager.lua b/toolchain/lib/packager.lua
index 6372fe1..c88e463 100644
--- a/toolchain/lib/packager.lua
+++ b/toolchain/lib/packager.lua
@@ -97,7 +97,8 @@ end
 -- The generated manifest uses archive mode (strip=1) and includes the
 -- computed sha256 of the binary tarball. Optional fields (deps, files,
 -- test) are included when present in the recipe.
-function packager.write_manifest(recipe, tarball_sha256, pkg_dir)
+function packager.write_manifest(recipe, tarball_sha256, pkg_dir, repo)
+  local repo = repo or "https://raw.githubusercontent.com/gretagen/zeta-packages/refs/heads/main"
   local lines = {}
   local function emit(fmt, ...)
     lines[#lines + 1] = string.format(fmt, ...)
@@ -107,8 +108,8 @@ function packager.write_manifest(recipe, tarball_sha256, pkg_dir)
   emit('  name    = "%s",', recipe.name)
   emit('  version = "%s",', recipe.version)
   emit('  summary = "%s",', escape(recipe.summary))
-  emit('  url     = "https://github.com/gretagen/zeta-packages/packages/%s/%s-%s.tar.gz",',
-    recipe.name, recipe.name, recipe.version)
+  emit('  url     = "%s/packages/%s/%s-%s.tar.gz",',
+    repo, recipe.name, recipe.name, recipe.version)
   emit('  sha256  = "%s",', tarball_sha256)
 
   if #recipe.deps > 0 then