diff --git a/.github/workflows/docs.yml b/.github/workflows/docs.yml
index 7007f18..230f393 100644
--- a/.github/workflows/docs.yml
+++ b/.github/workflows/docs.yml
@@ -19,6 +19,8 @@ env:
 jobs:
   docs:
     name: Documentation
+    # Only run this job on the main branch
+    if: github.ref == 'refs/heads/main'
     runs-on: ubuntu-latest
     environment:
       name: github-pages
@@ -65,16 +67,14 @@ jobs:
       continue-on-error: true
     
     - name: Setup Pages
-      if: github.ref == 'refs/heads/main'
       uses: actions/configure-pages@v4
       
+    # Upload the 'github-pages' artifact
     - name: Upload artifact
-      if: github.ref == 'refs/heads/main'
       uses: actions/upload-pages-artifact@v3
       with:
         path: ./target/doc
         
     - name: Deploy to GitHub Pages
-      if: github.ref == 'refs/heads/main'
       id: deployment
       uses: actions/deploy-pages@v4
diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..43f7c78
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,9 @@
+[submodule "external/spdm-lib"]
+	path = external/spdm-lib
+	url = git@github.com:OpenPRoT/spdm-lib.git
+[submodule "external/pldm-lib"]
+	path = external/pldm-lib
+	url = git@github.com:OpenPRoT/pldm-lib.git
+[submodule "external/mctp-lib"]
+	path = external/mctp-lib
+	url = git@github.com:OpenPRoT/mctp-lib.git
diff --git a/external/mctp-lib b/external/mctp-lib
new file mode 160000
index 0000000..23e6f7e
--- /dev/null
+++ b/external/mctp-lib
@@ -0,0 +1 @@
+Subproject commit 23e6f7e77d954e6bd3f71e0c7825376a4aa406e1
diff --git a/external/pldm-lib b/external/pldm-lib
new file mode 160000
index 0000000..756c42a
--- /dev/null
+++ b/external/pldm-lib
@@ -0,0 +1 @@
+Subproject commit 756c42aa51836161a775fc2dd0d09031b789f036
diff --git a/external/spdm-lib b/external/spdm-lib
new file mode 160000
index 0000000..26996f2
--- /dev/null
+++ b/external/spdm-lib
@@ -0,0 +1 @@
+Subproject commit 26996f258edb593fc276c35f45e6157447b7b631