diff --git a/.github/workflows/app-ci.yml b/.github/workflows/app-ci.yml
index 5995ec817..23be03e58 100644
--- a/.github/workflows/app-ci.yml
+++ b/.github/workflows/app-ci.yml
@@ -33,6 +33,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
           persist-credentials: false
 
       - name: Set up Python
@@ -84,6 +85,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
           persist-credentials: false
 
       - name: Install pnpm
@@ -133,3 +135,11 @@ jobs:
           NARUON_FULL_PRODUCT_BASE_URL: "http://127.0.0.1:3001"
           NARUON_FULL_PRODUCT_SCREENSHOT_DIR: "/tmp/naruon-full-product-smoke"
         run: cd frontend && pnpm run full:smoke
+
+      - name: Retain full product smoke PNG evidence
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
+        with:
+          name: naruon-full-product-smoke-${{ github.event.pull_request.number || github.run_id }}-${{ github.event.pull_request.head.sha || github.sha }}
+          path: /tmp/naruon-full-product-smoke-*/*.png
+          if-no-files-found: error
+          retention-days: 14
diff --git a/.github/workflows/bandit.yml b/.github/workflows/bandit.yml
index 0e250389c..81fe5ad42 100644
--- a/.github/workflows/bandit.yml
+++ b/.github/workflows/bandit.yml
@@ -23,6 +23,7 @@ jobs:
 
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
           persist-credentials: false
 
       - name: Set up Python
diff --git a/.github/workflows/dependency-review.yml b/.github/workflows/dependency-review.yml
index 21e607f7b..2d968e5b3 100644
--- a/.github/workflows/dependency-review.yml
+++ b/.github/workflows/dependency-review.yml
@@ -27,6 +27,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
           persist-credentials: false
 
       - name: Log dependency review policy
diff --git a/.github/workflows/docker-publish.yml b/.github/workflows/docker-publish.yml
index dd1015812..f69f35e37 100644
--- a/.github/workflows/docker-publish.yml
+++ b/.github/workflows/docker-publish.yml
@@ -55,6 +55,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
           persist-credentials: false
 
       - name: Set up QEMU
@@ -208,6 +209,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
           persist-credentials: false
 
       - name: Read release version
diff --git a/backend/tests/test_application_ci_evidence.py b/backend/tests/test_application_ci_evidence.py
new file mode 100644
index 000000000..7d60ce731
--- /dev/null
+++ b/backend/tests/test_application_ci_evidence.py
@@ -0,0 +1,43 @@
+"""Guard hosted buyer-facing evidence retention in Application CI."""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+import yaml
+
+
+REPO_ROOT = Path(__file__).resolve().parents[2]
+APPLICATION_CI_PATH = REPO_ROOT / ".github/workflows/app-ci.yml"
+UPLOAD_ARTIFACT_SHA = "043fb46d1a93c77aae656e7c1c64a875d1fc6a0a"
+
+
+def test_application_ci_retains_full_product_smoke_screenshot_evidence() -> None:
+    """A passing browser smoke must publish PR-head-bound PNG evidence instead of discarding it."""
+    workflow_text = APPLICATION_CI_PATH.read_text(encoding="utf-8")
+    workflow = yaml.load(workflow_text, Loader=yaml.BaseLoader)
+    frontend_steps = workflow["jobs"]["frontend"]["steps"]
+
+    smoke_indices = [
+        index
+        for index, step in enumerate(frontend_steps)
+        if step.get("name") == "Run full product smoke"
+    ]
+    upload_indices = [
+        index
+        for index, step in enumerate(frontend_steps)
+        if step.get("uses", "").startswith("actions/upload-artifact@")
+    ]
+
+    assert len(smoke_indices) == 1
+    assert len(upload_indices) == 1
+    assert upload_indices[0] == smoke_indices[0] + 1
+
+    upload_step = frontend_steps[upload_indices[0]]
+    assert upload_step["uses"] == f"actions/upload-artifact@{UPLOAD_ARTIFACT_SHA}"
+    assert upload_step["with"] == {
+        "name": "naruon-full-product-smoke-${{ github.event.pull_request.number || github.run_id }}-${{ github.event.pull_request.head.sha || github.sha }}",
+        "path": "/tmp/naruon-full-product-smoke-*/*.png",
+        "if-no-files-found": "error",
+        "retention-days": "14",
+    }
diff --git a/backend/tests/test_repo_local_pr_exact_head.py b/backend/tests/test_repo_local_pr_exact_head.py
new file mode 100644
index 000000000..ed2374df5
--- /dev/null
+++ b/backend/tests/test_repo_local_pr_exact_head.py
@@ -0,0 +1,35 @@
+"""Guard exact-head source checkout in repository-owned pull-request validation."""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+import yaml
+
+
+REPO_ROOT = Path(__file__).resolve().parents[2]
+PR_VALIDATION_WORKFLOWS = (
+    ".github/workflows/app-ci.yml",
+    ".github/workflows/bandit.yml",
+    ".github/workflows/dependency-review.yml",
+    ".github/workflows/docker-publish.yml",
+)
+EXPECTED_EXACT_REF = "${{ github.event.pull_request.head.sha || github.sha }}"
+
+
+@pytest.mark.parametrize("workflow_path", PR_VALIDATION_WORKFLOWS)
+def test_repo_local_validation_checks_out_exact_pr_head(workflow_path: str) -> None:
+    """Do not report pull-request merge-tree execution as exact-head validation."""
+    workflow_text = (REPO_ROOT / workflow_path).read_text(encoding="utf-8")
+    workflow = yaml.load(workflow_text, Loader=yaml.BaseLoader)
+    checkout_steps = [
+        step
+        for job in workflow["jobs"].values()
+        for step in job.get("steps", [])
+        if step.get("uses", "").startswith("actions/checkout@")
+    ]
+
+    assert checkout_steps
+    for checkout_step in checkout_steps:
+        assert checkout_step.get("with", {}).get("ref") == EXPECTED_EXACT_REF