diff --git a/.github/workflows/pr-build-main.yml b/.github/workflows/pr-build-main.yml
index e066df2a41ffe..5195db4f27b2e 100644
--- a/.github/workflows/pr-build-main.yml
+++ b/.github/workflows/pr-build-main.yml
@@ -21,6 +21,7 @@ on:
   pull_request:
     branches:
       - main
+      - reduceGitFetchTimeForScalpel-base-for-pr
     # CI-only changes don't need a full build. Use workflow_dispatch to
     # test CI changes: gh workflow run "Build and test" -f pr_number=XXXX -f pr_ref=branch-name
     paths-ignore:
@@ -92,7 +93,7 @@ jobs:
           # Scalpel is observational — fetch failures must not break the build.
           BASE_REF="${GITHUB_BASE_REF:-main}"
           for depth in 50 200 1000; do
-            git fetch --deepen=$depth 2>/dev/null || true
+            git fetch --no-tags --deepen=$depth origin ${BASE_REF} 2>/dev/null || true
             git fetch --no-tags --depth=$depth origin "${BASE_REF}:refs/remotes/origin/${BASE_REF}" 2>/dev/null || true
             if git merge-base HEAD "origin/${BASE_REF}" >/dev/null 2>&1; then
               echo "Merge base reachable at depth $depth"
@@ -103,7 +104,7 @@ jobs:
           # If still not reachable, fetch full history as last resort
           if ! git merge-base HEAD "origin/${BASE_REF}" >/dev/null 2>&1; then
             echo "Merge base still not reachable, fetching full history"
-            git fetch --unshallow 2>/dev/null || true
+            git fetch --no-tags --unshallow origin ${BASE_REF} 2>/dev/null || true
             git fetch --no-tags origin "${BASE_REF}:refs/remotes/origin/${BASE_REF}" 2>/dev/null || true
           fi
       - id: install-packages
diff --git a/.github/workflows/sonar-build.yml b/.github/workflows/sonar-build.yml
index b6f5c100896e0..d1bbc3e99be6a 100644
--- a/.github/workflows/sonar-build.yml
+++ b/.github/workflows/sonar-build.yml
@@ -50,7 +50,7 @@ jobs:
           # Scalpel is observational — fetch failures must not break the build.
           BASE_REF="${GITHUB_BASE_REF:-main}"
           for depth in 200 1000; do
-            git fetch --deepen=$depth 2>/dev/null || true
+            git fetch --no-tags --deepen=$depth origin ${BASE_REF} 2>/dev/null || true
             git fetch --no-tags --depth=$depth origin "${BASE_REF}:refs/remotes/origin/${BASE_REF}" || true
             if git merge-base HEAD "origin/${BASE_REF}" >/dev/null 2>&1; then
               echo "Merge base reachable at depth $depth"
@@ -61,7 +61,7 @@ jobs:
           # If still not reachable, fetch full history as last resort
           if ! git merge-base HEAD "origin/${BASE_REF}" >/dev/null 2>&1; then
             echo "Merge base still not reachable, fetching full history"
-            git fetch --unshallow 2>/dev/null || true
+            git fetch --no-tags --unshallow origin ${BASE_REF} 2>/dev/null || true
             git fetch --no-tags origin "${BASE_REF}:refs/remotes/origin/${BASE_REF}" || true
           fi
       - id: install-packages