diff --git a/config/scripts/build-source-commit.mjs b/config/scripts/build-source-commit.mjs
index 70aece6..e680be0 100644
--- a/config/scripts/build-source-commit.mjs
+++ b/config/scripts/build-source-commit.mjs
@@ -5,6 +5,13 @@ import { execFileSync } from 'node:child_process'
  * skills an Orca build installs are the ones it bundles on every release channel.
  */
 export function resolveBuildSourceCommit() {
+  // A build system compiling from a source archive (no git checkout) can pin the
+  // source ref (a tag or branch) explicitly via ORCA_BUILD_COMMIT; prefer it over
+  // the local HEAD so skill installs clone a ref that exists on the remote.
+  const pinned = (process.env.ORCA_BUILD_COMMIT || '').trim()
+  if (pinned) {
+    return pinned
+  }
   let commit = ''
   try {
     commit = execFileSync('git', ['rev-parse', 'HEAD'], { encoding: 'utf8' }).trim()