diff --git a/docs/release-control/v6/internal/records/release-acceleration-v6.3.0-rc.5-2026-08-21.md b/docs/release-control/v6/internal/records/release-acceleration-v6.3.0-rc.5-2026-08-21.md
index 0e7e79b54..59e193e69 100644
--- a/docs/release-control/v6/internal/records/release-acceleration-v6.3.0-rc.5-2026-08-21.md
+++ b/docs/release-control/v6/internal/records/release-acceleration-v6.3.0-rc.5-2026-08-21.md
@@ -131,6 +131,16 @@ artifact client, and performs heavyweight disk cleanup only below an explicit
 8 GiB safety floor. Exact Pulse and pulse-enterprise SHA manifests remain the
 authority on both sides of the credential boundary.
 
+The first non-publishing exact-SHA proof of that lean profile failed before Pro
+compilation because the public server packages require
+`frontend-modern/dist` as an embed source even though Pro never transfers the
+frontend as a standalone payload. The corrected profile builds that exact-SHA
+embed prerequisite concurrently with the public-agent matrix, leaves it in the
+source checkout for the five Pro builds, and still excludes it from the
+manifest-covered cross-repository payload. A governed regression test preserves
+the distinction between a required local compile input and an unused transfer
+product.
+
 Public Docker publication took 5 minutes 1 second, but its prior dependency
 shape did not make it eligible until 12 minutes 33 seconds after dispatch. The
 corrected DAG makes exact-version Docker staging eligible as soon as the
diff --git a/docs/release-control/v6/internal/subsystems/deployment-installability.md b/docs/release-control/v6/internal/subsystems/deployment-installability.md
index 6b65adb68..a8b08e6ea 100644
--- a/docs/release-control/v6/internal/subsystems/deployment-installability.md
+++ b/docs/release-control/v6/internal/subsystems/deployment-installability.md
@@ -549,8 +549,11 @@ upgrade, update, release, or artifact-selection behavior.
    Private Pro compilation must additionally bind the exact Pulse and
    pulse-enterprise commits in a manifest-covered identity record. Its PVE job
    must compile only the public Unified Agent matrix actually embedded in Pro
-   archives plus the Pro server matrix; rebuilding the unused public frontend,
-   MCP, server, or control-plane payload is not part of this boundary. The
+   archives plus the Pro server matrix. The public frontend build is a required
+   source-checkout prerequisite because every Pro server embeds that exact-SHA
+   bundle, so it must overlap the public-agent matrix but must not enter the
+   transferred payload. Rebuilding the unused public MCP, server, or
+   control-plane payload is not part of this boundary. The
    cross-repository handoff must remain manifest-bound, use compressed artifact
    transfer, and let a hosted runner with sufficient free space skip destructive
    image/toolchain cleanup. The hosted private job must verify both SHAs before
diff --git a/scripts/build-release-binaries.sh b/scripts/build-release-binaries.sh
index 2cb260a9f..1f44ad106 100755
--- a/scripts/build-release-binaries.sh
+++ b/scripts/build-release-binaries.sh
@@ -89,14 +89,23 @@ if [[ -e "${OUTPUT_ROOT}" ]] && find "${OUTPUT_ROOT}" -mindepth 1 -print -quit |
 fi
 mkdir -p "${BINARIES_DIR}" "${MANIFEST_DIR}"
 
-if [[ "${PROFILE}" == "full" ]]; then
-    mkdir -p "${FRONTEND_DIR}"
-    echo "Building exact-SHA frontend bundle..."
+build_frontend() {
+    echo "Building exact-SHA frontend embed prerequisite..."
     npm --prefix frontend-modern ci
     npm --prefix frontend-modern run build
-    cp -a frontend-modern/dist/. "${FRONTEND_DIR}/"
+    if [[ "${PROFILE}" == "full" ]]; then
+        mkdir -p "${FRONTEND_DIR}"
+        cp -a frontend-modern/dist/. "${FRONTEND_DIR}/"
+    fi
+}
+
+frontend_log="${OUTPUT_ROOT}/frontend.log"
+build_frontend >"${frontend_log}" 2>&1 &
+frontend_pid=$!
+if [[ "${PROFILE}" == "full" ]]; then
+    echo "Building frontend bundle concurrently with the release binary matrix."
 else
-    echo "Using Pro packaging profile: public Unified Agent binaries only."
+    echo "Using Pro packaging profile: build the required frontend embed locally; transfer public Unified Agent binaries only."
 fi
 
 export CGO_ENABLED=0
@@ -191,6 +200,11 @@ terminate_active() {
         [[ -n "${pid}" ]] && terminate_tree "${pid}"
     done
     wait "${active_pids[@]:-}" >/dev/null 2>&1 || true
+    if [[ -n "${frontend_pid:-}" ]]; then
+        terminate_tree "${frontend_pid}"
+        wait "${frontend_pid}" >/dev/null 2>&1 || true
+        frontend_pid=""
+    fi
 }
 trap terminate_active INT TERM
 
@@ -234,6 +248,19 @@ while (( completed_tasks < total_tasks )); do
     completed_tasks=$((completed_tasks + 1))
     echo "Compiled ${task_name} (${completed_tasks}/${total_tasks})."
 done
+
+if wait "${frontend_pid}"; then
+    status=0
+else
+    status=$?
+    echo "Error: frontend embed prerequisite failed." >&2
+    cat "${frontend_log}" >&2
+    frontend_pid=""
+    exit "${status}"
+fi
+frontend_pid=""
+rm -f "${frontend_log}"
+echo "Built frontend embed prerequisite."
 trap - INT TERM
 
 python3 scripts/release_candidate_manifest.py create \
diff --git a/scripts/installtests/build_release_assets_test.go b/scripts/installtests/build_release_assets_test.go
index 53d3c8058..ca5ee7e58 100644
--- a/scripts/installtests/build_release_assets_test.go
+++ b/scripts/installtests/build_release_assets_test.go
@@ -142,6 +142,33 @@ func TestBuildReleaseUsesV6InstallScripts(t *testing.T) {
 	}
 }
 
+func TestProPackagingBuildsFrontendEmbedWithoutTransferringBundle(t *testing.T) {
+	content, err := os.ReadFile(repoFile("scripts", "build-release-binaries.sh"))
+	if err != nil {
+		t.Fatalf("read build-release-binaries.sh: %v", err)
+	}
+	script := string(content)
+
+	for _, needle := range []string{
+		`build_frontend >"${frontend_log}" 2>&1 &`,
+		`npm --prefix frontend-modern ci`,
+		`npm --prefix frontend-modern run build`,
+		`if [[ "${PROFILE}" == "full" ]]; then`,
+		`cp -a frontend-modern/dist/. "${FRONTEND_DIR}/"`,
+		`transfer public Unified Agent binaries only`,
+	} {
+		if !strings.Contains(script, needle) {
+			t.Fatalf("build-release-binaries.sh missing Pro frontend embed contract: %s", needle)
+		}
+	}
+	if strings.Contains(script, `if [[ "${PROFILE}" == "full" ]]; then
+	    mkdir -p "${FRONTEND_DIR}"
+	    echo "Building exact-SHA frontend bundle..."
+	    npm --prefix frontend-modern ci`) {
+		t.Fatal("Pro packaging must build the frontend embed prerequisite")
+	}
+}
+
 func TestReleaseContainerTargetsConsumeImmutableCandidate(t *testing.T) {
 	dockerfileBytes, err := os.ReadFile(repoFile("Dockerfile"))
 	if err != nil {