diff --git a/infra/k8s/argo/ci-pipeline-template.yaml b/infra/k8s/argo/ci-pipeline-template.yaml
index d9cbeb406..b79183da1 100644
--- a/infra/k8s/argo/ci-pipeline-template.yaml
+++ b/infra/k8s/argo/ci-pipeline-template.yaml
@@ -662,7 +662,7 @@ spec:
             SHA="{{workflow.parameters.commit-sha}}"
             SERVICE_PKGS="{{inputs.parameters.service-packages}}"
 
-            # Git clone (self-contained)
+            # SSH setup
             mkdir -p ~/.ssh
             cp /etc/git-ssh/ssh-privatekey ~/.ssh/id_ed25519
             chmod 600 ~/.ssh/id_ed25519
@@ -670,10 +670,22 @@ spec:
             chmod 600 ~/.ssh/config
 
             REPO="ssh://git@gitlab-gitlab-shell.foxhunt.svc.cluster.local:2222/root/foxhunt.git"
-            WORKSPACE="/tmp/workspace"
-            git clone --no-checkout --filter=blob:none "$REPO" "$WORKSPACE"
-            cd "$WORKSPACE"
-            git checkout "$SHA"
+            WORKSPACE="/cargo-target/src"
+
+            # Persistent checkout on PVC — git checkout only touches changed files,
+            # preserving mtimes on unchanged files so cargo skips recompiling them
+            if [ -d "$WORKSPACE/.git" ]; then
+              echo "=== Updating persistent checkout ==="
+              cd "$WORKSPACE"
+              git fetch origin
+              git checkout --force "$SHA"
+              git clean -fdx
+            else
+              echo "=== Initial clone (first run) ==="
+              git clone --filter=blob:none "$REPO" "$WORKSPACE"
+              cd "$WORKSPACE"
+              git checkout "$SHA"
+            fi
             echo "Checked out $(git rev-parse --short HEAD)"
 
             # Ensure cargo home registry is on PVC
@@ -681,12 +693,12 @@ spec:
 
             export FOXHUNT_BUILD_VERSION="{{inputs.parameters.tag}}"
 
-            # Prune target dir if it exceeds 25GB (prevents unbounded PVC growth)
+            # Prune build artifacts if PVC exceeds 25GB (prevents unbounded growth)
             TARGET_SIZE_MB=$(du -sm "$CARGO_TARGET_DIR" 2>/dev/null | cut -f1 || echo 0)
-            echo "Cargo target dir: ${TARGET_SIZE_MB}MB"
+            echo "PVC usage: ${TARGET_SIZE_MB}MB"
             if [ "$TARGET_SIZE_MB" -gt 25000 ]; then
-              echo "Target dir exceeds 25GB limit, running cargo clean..."
-              cargo clean
+              echo "PVC exceeds 25GB limit, pruning build artifacts..."
+              rm -rf "$CARGO_TARGET_DIR/release" "$CARGO_TARGET_DIR/debug"
             fi
 
             # Guard: empty package list would build entire workspace
@@ -805,7 +817,7 @@ spec:
             SHA="{{workflow.parameters.commit-sha}}"
             TRAINING_EXAMPLES="{{inputs.parameters.training-examples}}"
 
-            # Git clone (self-contained — ephemeral node)
+            # SSH setup
             mkdir -p ~/.ssh
             cp /etc/git-ssh/ssh-privatekey ~/.ssh/id_ed25519
             chmod 600 ~/.ssh/id_ed25519
@@ -813,10 +825,22 @@ spec:
             chmod 600 ~/.ssh/config
 
             REPO="ssh://git@gitlab-gitlab-shell.foxhunt.svc.cluster.local:2222/root/foxhunt.git"
-            WORKSPACE="/tmp/workspace"
-            git clone --no-checkout --filter=blob:none "$REPO" "$WORKSPACE"
-            cd "$WORKSPACE"
-            git checkout "$SHA"
+            WORKSPACE="/cargo-target/src"
+
+            # Persistent checkout on PVC — git checkout only touches changed files,
+            # preserving mtimes on unchanged files so cargo skips recompiling them
+            if [ -d "$WORKSPACE/.git" ]; then
+              echo "=== Updating persistent checkout ==="
+              cd "$WORKSPACE"
+              git fetch origin
+              git checkout --force "$SHA"
+              git clean -fdx
+            else
+              echo "=== Initial clone (first run) ==="
+              git clone --filter=blob:none "$REPO" "$WORKSPACE"
+              cd "$WORKSPACE"
+              git checkout "$SHA"
+            fi
             echo "Checked out $(git rev-parse --short HEAD)"
 
             # Ensure cargo home registry is on PVC
@@ -825,12 +849,12 @@ spec:
             export FOXHUNT_BUILD_VERSION="{{inputs.parameters.tag}}"
             export CUDA_COMPUTE_CAP={{workflow.parameters.cuda-compute-cap}}
 
-            # Prune target dir if it exceeds 25GB (prevents unbounded PVC growth)
+            # Prune build artifacts if PVC exceeds 25GB (prevents unbounded growth)
             TARGET_SIZE_MB=$(du -sm "$CARGO_TARGET_DIR" 2>/dev/null | cut -f1 || echo 0)
-            echo "Cargo target dir: ${TARGET_SIZE_MB}MB"
+            echo "PVC usage: ${TARGET_SIZE_MB}MB"
             if [ "$TARGET_SIZE_MB" -gt 25000 ]; then
-              echo "Target dir exceeds 25GB limit, running cargo clean..."
-              cargo clean
+              echo "PVC exceeds 25GB limit, pruning build artifacts..."
+              rm -rf "$CARGO_TARGET_DIR/release" "$CARGO_TARGET_DIR/debug"
             fi
 
             # Separate ml examples from training_uploader (different build commands)
diff --git a/infra/k8s/argo/compile-and-train-template.yaml b/infra/k8s/argo/compile-and-train-template.yaml
index a9e4d43a9..83f13bfc5 100644
--- a/infra/k8s/argo/compile-and-train-template.yaml
+++ b/infra/k8s/argo/compile-and-train-template.yaml
@@ -144,6 +144,8 @@ spec:
             value: always
           - name: CARGO_TARGET_DIR
             value: /cargo-target
+          - name: CARGO_HOME
+            value: /cargo-target/cargo-home
           - name: GITLAB_PAT
             valueFrom:
               secretKeyRef:
@@ -167,7 +169,7 @@ spec:
             set -e
             SHA="{{workflow.parameters.commit-sha}}"
 
-            # Git clone
+            # SSH setup
             mkdir -p ~/.ssh
             cp /etc/git-ssh/ssh-privatekey ~/.ssh/id_ed25519
             chmod 600 ~/.ssh/id_ed25519
@@ -175,21 +177,36 @@ spec:
             chmod 600 ~/.ssh/config
 
             REPO="ssh://git@gitlab-gitlab-shell.foxhunt.svc.cluster.local:2222/root/foxhunt.git"
-            BUILD="/tmp/workspace"
-            git clone --no-checkout --filter=blob:none "$REPO" "$BUILD"
-            cd "$BUILD"
-            git checkout "$SHA"
+            BUILD="/cargo-target/src"
+
+            # Persistent checkout on PVC — git checkout only touches changed files,
+            # preserving mtimes on unchanged files so cargo skips recompiling them
+            if [ -d "$BUILD/.git" ]; then
+              echo "=== Updating persistent checkout ==="
+              cd "$BUILD"
+              git fetch origin
+              git checkout --force "$SHA"
+              git clean -fdx
+            else
+              echo "=== Initial clone (first run) ==="
+              git clone --filter=blob:none "$REPO" "$BUILD"
+              cd "$BUILD"
+              git checkout "$SHA"
+            fi
             SHORT_SHA=$(git rev-parse --short HEAD)
             echo "Checked out ${SHORT_SHA}"
 
+            # Ensure cargo home registry is on PVC
+            export PATH="${CARGO_HOME}/bin:${PATH}"
+
             export CUDA_COMPUTE_CAP={{workflow.parameters.cuda-compute-cap}}
 
-            # Prune target dir if it exceeds 25GB (prevents unbounded PVC growth)
+            # Prune build artifacts if PVC exceeds 25GB (prevents unbounded growth)
             TARGET_SIZE_MB=$(du -sm "$CARGO_TARGET_DIR" 2>/dev/null | cut -f1 || echo 0)
-            echo "Cargo target dir: ${TARGET_SIZE_MB}MB"
+            echo "PVC usage: ${TARGET_SIZE_MB}MB"
             if [ "$TARGET_SIZE_MB" -gt 25000 ]; then
-              echo "Target dir exceeds 25GB limit, running cargo clean..."
-              cargo clean
+              echo "PVC exceeds 25GB limit, pruning build artifacts..."
+              rm -rf "$CARGO_TARGET_DIR/release" "$CARGO_TARGET_DIR/debug"
             fi
 
             # Derive needed binaries from model parameter (only build what's used)