diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index da92674e5..154c30388 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -61,51 +61,139 @@ jobs:
         with:
           ruby-version: '3.0'
 
+      - name: Resolve repository/ref overrides
+        id: resolve
+        shell: bash
+        run: |
+          set -euo pipefail
+
+          parse() {
+            local SRC="$1"; shift
+            local DEF_REPO="$1"; shift
+            local DEF_REF="$1"; shift
+            local PREFIX="$1"; shift
+            local REPO="$DEF_REPO"
+            local REF="$DEF_REF"
+
+            if [[ -n "${SRC}" ]]; then
+              # Normalize common GitHub notations into OWNER/REPO and REF
+              # Supported forms:
+              #  - owner/repo@ref
+              #  - owner/repo#ref
+              #  - owner/repo/branch@ref (branch path ignored, ref used)
+              #  - owner/repo/branch (no @/# → use branch as ref)
+              #  - https://github.com/owner/repo@ref
+              #  - https://github.com/owner/repo/branch@ref
+              #  - git@github.com:owner/repo@ref
+              #  - plain "branchOrSha" (no /) → use default repo with given ref
+
+              local VAL="$SRC"
+              # Strip URL/SSH prefixes if present
+              if [[ "$VAL" =~ ^https?://github.com/ ]]; then
+                VAL="${VAL#*github.com/}"
+              elif [[ "$VAL" =~ ^git@github.com: ]]; then
+                VAL="${VAL#git@github.com:}"
+              fi
+
+              # Split at @ or # if present
+              local BASE="$VAL"
+              if [[ "$VAL" == *"@"* ]]; then
+                BASE="${VAL%%@*}"
+                REF="${VAL#*@}"
+              elif [[ "$VAL" == *"#"* ]]; then
+                BASE="${VAL%%#*}"
+                REF="${VAL#*#}"
+              fi
+
+              # If BASE contains owner/repo[/...]
+              if [[ "$BASE" == */* ]]; then
+                # Extract first two segments as owner/repo
+                local OWNER="${BASE%%/*}"
+                local REST="${BASE#*/}"
+                local REPO_NAME="${REST%%/*}"
+                # remove potential .git suffix from repo name
+                REPO_NAME="${REPO_NAME%.git}"
+                if [[ -n "$OWNER" && -n "$REPO_NAME" ]]; then
+                  REPO="$OWNER/$REPO_NAME"
+                  # If no explicit @/# ref was provided and there is a third segment, use it as ref
+                  if [[ "$VAL" != *"@"* && "$VAL" != *"#"* ]]; then
+                    local REMREST="${REST#*/}"
+                    if [[ "$REMREST" != "$REST" && -n "$REMREST" ]]; then
+                      REF="${REMREST%%/*}"
+                    fi
+                  fi
+                fi
+              else
+                # No slash → treat as branch/SHA on default repo
+                if [[ -n "$BASE" ]]; then
+                  REF="$BASE"
+                fi
+              fi
+            fi
+
+            echo "${PREFIX}_REPO=${REPO}" >> "$GITHUB_OUTPUT"
+            echo "${PREFIX}_REF=${REF}" >> "$GITHUB_OUTPUT"
+            echo "Resolved ${PREFIX}: ${REPO}@${REF}"
+          }
+
+          # Antora UI
+          parse "${{ inputs.Antora_UI_Hash }}" "KhronosGroup/antora-ui-khronos" "main" "UI"
+          # GLSL
+          parse "${{ inputs.GLSL_Commit_Hash }}" "KhronosGroup/GLSL" "main" "GLSL"
+          # Vulkan Guide
+          parse "${{ inputs.Guide_Commit_Hash }}" "KhronosGroup/Vulkan-Guide" "main" "GUIDE"
+          # Vulkan Docs
+          parse "${{ inputs.DOC_Commit_Hash }}" "KhronosGroup/Vulkan-Docs" "main" "DOCS"
+          # Vulkan Samples
+          parse "${{ inputs.Samples_Commit_Hash }}" "KhronosGroup/Vulkan-Samples" "main" "SAMPLES"
+          # Vulkan Tutorial
+          parse "${{ inputs.Tutorial_Commit_Hash }}" "KhronosGroup/Vulkan-Tutorial" "main" "TUTORIAL"
+
       - name: "checkout Antora UI"
         uses: actions/checkout@v4
         with:
-          repository: KhronosGroup/antora-ui-khronos
+          repository: ${{ steps.resolve.outputs.UI_REPO }}
           path: ./antora-ui-khronos
-          ref: ${{ inputs.Antora_UI_Hash > '' && inputs.Antora_UI_Hash || 'main' }}
+          ref: ${{ steps.resolve.outputs.UI_REF }}
 
       - name: "checkout GLSL"
         uses: actions/checkout@v4
         with:
-          repository: KhronosGroup/GLSL
+          repository: ${{ steps.resolve.outputs.GLSL_REPO }}
           path: ./GLSL
-          ref: ${{ inputs.GLSL_Commit_Hash > '' && inputs.GLSL_Commit_Hash || 'main' }}
+          ref: ${{ steps.resolve.outputs.GLSL_REF }}
           submodules: recursive
 
       - name: "checkout Vulkan Guide"
         uses: actions/checkout@v4
         with:
-          repository: KhronosGroup/Vulkan-Guide
+          repository: ${{ steps.resolve.outputs.GUIDE_REPO }}
           path: ./Vulkan-Guide
-          ref: ${{ inputs.Guide_Commit_Hash > '' && inputs.Guide_Commit_Hash || 'main' }}
+          ref: ${{ steps.resolve.outputs.GUIDE_REF }}
           submodules: recursive
 
       - name: "Checkout Vulkan Docs"
         uses: actions/checkout@v4
         with:
-          repository: KhronosGroup/Vulkan-Docs
+          repository: ${{ steps.resolve.outputs.DOCS_REPO }}
           path: ./Vulkan-Docs
-          ref: ${{ inputs.DOC_Commit_Hash > '' && inputs.DOC_Commit_Hash || 'main' }}
+          ref: ${{ steps.resolve.outputs.DOCS_REF }}
           submodules: recursive
 
       - name: "Checkout Vulkan Samples"
         uses: actions/checkout@v4
         with:
-          repository: KhronosGroup/Vulkan-Samples
+          repository: ${{ steps.resolve.outputs.SAMPLES_REPO }}
           path: ./Vulkan-Samples
-          ref: ${{ inputs.Samples_Commit_Hash > '' && inputs.Samples_Commit_Hash || 'main' }}
+          ref: ${{ steps.resolve.outputs.SAMPLES_REF }}
           submodules: recursive
 
       - name: "Checkout Vulkan Tutorial"
         uses: actions/checkout@v4
         with:
-          repository: KhronosGroup/Vulkan-Tutorial
+          repository: ${{ steps.resolve.outputs.TUTORIAL_REPO }}
           path: ./Vulkan-Tutorial
-          ref: ${{ inputs.Tutorial_Commit_Hash > '' && inputs.Tutorial_Commit_Hash || 'main' }}
+          ref: ${{ steps.resolve.outputs.TUTORIAL_REF }}
           submodules: recursive
 
       - name: "setup npm"
diff --git a/antora-ui-khronos b/antora-ui-khronos
index ac0b12aad..595ae245b 160000
--- a/antora-ui-khronos
+++ b/antora-ui-khronos
@@ -1 +1 @@
-Subproject commit ac0b12aadf11db0625445dd5c3eaf374f1176df8
+Subproject commit 595ae245bbce027e4edfd1894bb88d33a505e660