diff --git a/.gitea/workflows/cicd-checks.yaml b/.gitea/workflows/cicd-checks.yaml
index 299ef58..21e7a20 100644
--- a/.gitea/workflows/cicd-checks.yaml
+++ b/.gitea/workflows/cicd-checks.yaml
@@ -106,6 +106,59 @@ jobs:
           echo "=== Kernel Tail ==="
           dmesg | tail -n 120 || true
 
+  dockerfile-boundary-check:
+    name: Dockerfile Runtime Boundary Check
+    runs-on: ubuntu-act
+    timeout-minutes: 10
+    needs: setup
+    steps:
+      - name: Configure registry host resolution
+        run: |
+          if ! grep -q "${GITEA_REGISTRY_HOST}" /etc/hosts; then
+            echo "${GITEA_REGISTRY_IP} ${GITEA_REGISTRY_HOST}" >> /etc/hosts
+          fi
+
+      - name: Ensure CICD image is available
+        env:
+          HEAD_SHA: ${{ needs.setup.outputs.head_sha }}
+        run: |
+          IMAGE="${GITEA_REGISTRY}/darkhelm.org/plex-playlist-cicd:${HEAD_SHA}"
+          if docker image inspect "${IMAGE}" >/dev/null 2>&1; then
+            echo "Using cached CICD image: ${IMAGE}"
+          else
+            echo "${{ secrets.PACKAGE_ACCESS_TOKEN }}" | docker login "http://${GITEA_REGISTRY}" -u "${{ github.actor }}" --password-stdin
+            pulled=false
+            for i in 1 2 3; do
+              echo "Pull attempt ${i}/3 for ${IMAGE}"
+              if docker pull "${IMAGE}"; then
+                pulled=true
+                break
+              fi
+              if [ "${i}" -lt 3 ]; then
+                sleep_seconds=$((5 * i))
+                echo "Pull failed; retrying in ${sleep_seconds}s"
+                sleep "${sleep_seconds}"
+              fi
+            done
+
+            if [ "${pulled}" != "true" ]; then
+              echo "❌ Failed to pull CICD image after 3 attempts: ${IMAGE}"
+              exit 1
+            fi
+          fi
+
+      - name: Validate runtime Dockerfile boundaries in validation environment
+        env:
+          HEAD_SHA: ${{ needs.setup.outputs.head_sha }}
+        run: |
+          set -e
+          docker run --rm --entrypoint /bin/bash "${GITEA_REGISTRY}/darkhelm.org/plex-playlist-cicd:${HEAD_SHA}" -c "
+            cd /workspace &&
+            bash scripts/check-dockerfile-boundaries.sh
+          "
+
+      - *failure_diagnostics_step
+
   run-check:
     name: ${{ matrix.name }}
     # Run checks across the full act runner pool for maximum parallelism.
diff --git a/.gitea/workflows/docker-build-main.yaml b/.gitea/workflows/docker-build-main.yaml
index 0f0a44d..4b6e4d6 100644
--- a/.gitea/workflows/docker-build-main.yaml
+++ b/.gitea/workflows/docker-build-main.yaml
@@ -188,7 +188,7 @@ jobs:
           RESOLVED_HEAD_SHA="${HEAD_SHA_INPUT:-${HEAD_SHA_FALLBACK}}"
           echo "head_sha=${RESOLVED_HEAD_SHA}" >> "$GITHUB_OUTPUT"
 
-      - name: Minimal checkout for build inputs
+      - name: Minimal checkout for build and verification inputs
         env:
           SSH_PRIVATE_KEY: ${{ secrets.SSH_PRIVATE_KEY }}
           HEAD_SHA: ${{ steps.meta.outputs.head_sha }}
@@ -212,9 +212,45 @@ jobs:
           GIT_SSH_COMMAND="ssh -i ~/.ssh/id_rsa -o IdentitiesOnly=yes -o StrictHostKeyChecking=no" \
             git fetch --depth 1 origin "${HEAD_SHA}" >/dev/null 2>&1 || true
 
-          git checkout FETCH_HEAD -- Dockerfile.cicd Dockerfile.cicd-base .dockerignore scripts/compute-cicd-base-hash.sh
+          git checkout FETCH_HEAD -- \
+            .dockerignore \
+            Dockerfile.backend \
+            Dockerfile.frontend \
+            Dockerfile.cicd \
+            Dockerfile.cicd-base \
+            backend \
+            frontend \
+            scripts/compute-cicd-base-hash.sh \
+            scripts/check-dockerfile-boundaries.sh \
+            scripts/verify-deployable-image-purity.sh
           chmod +x scripts/compute-cicd-base-hash.sh
 
+      - name: Verify deployable runtime boundaries
+        run: |
+          set -e
+          bash ./scripts/check-dockerfile-boundaries.sh
+
+      - name: Build and verify deployable runtime image purity
+        env:
+          HEAD_SHA: ${{ steps.meta.outputs.head_sha }}
+        run: |
+          set -e
+
+          docker build -f Dockerfile.backend \
+            -t deployable-backend:"${HEAD_SHA}" .
+
+          docker build -f Dockerfile.frontend \
+            --target production \
+            -t deployable-frontend:"${HEAD_SHA}" .
+
+          bash ./scripts/verify-deployable-image-purity.sh \
+            --image deployable-backend:"${HEAD_SHA}" \
+            --profile backend
+
+          bash ./scripts/verify-deployable-image-purity.sh \
+            --image deployable-frontend:"${HEAD_SHA}" \
+            --profile frontend
+
       - name: Build and push complete CICD image
         env:
           PACKAGE_ACCESS_TOKEN: ${{ secrets.PACKAGE_ACCESS_TOKEN }}
diff --git a/Dockerfile.backend b/Dockerfile.backend
index 1dd820a..3328f64 100644
--- a/Dockerfile.backend
+++ b/Dockerfile.backend
@@ -19,6 +19,10 @@ ENV PATH="$VIRTUAL_ENV/bin:$PATH"
 
 # Copy dependency files first for better caching
 COPY backend/pyproject.toml backend/uv.lock* ./
+# Hatchling resolves the readme path ../README.md relative to the backend
+# package root (/app). Create a stub so metadata validation succeeds without
+# requiring the file to pass through .dockerignore.
+RUN echo '# plex-playlist' > /README.md
 
 # Install dependencies
 RUN uv sync --frozen
diff --git a/Dockerfile.frontend b/Dockerfile.frontend
index 6e128aa..be5d130 100644
--- a/Dockerfile.frontend
+++ b/Dockerfile.frontend
@@ -6,10 +6,11 @@ WORKDIR /app
 
 # Copy package files first for better caching
 COPY frontend/package*.json ./
+COPY frontend/.yarnrc.yml ./
 COPY frontend/yarn.lock* frontend/pnpm-lock.yaml* ./
 
 # Install dependencies
-RUN if [ -f yarn.lock ]; then yarn install; \
+RUN if [ -f yarn.lock ]; then corepack enable && corepack yarn install; \
     elif [ -f pnpm-lock.yaml ]; then npm install -g pnpm && pnpm install; \
     else npm install; fi
 
@@ -23,7 +24,7 @@ CMD ["npm", "run", "dev", "--", "--host", "0.0.0.0"]
 
 # Production build stage
 FROM base AS build
-RUN if [ -f yarn.lock ]; then yarn build; \
+RUN if [ -f yarn.lock ]; then corepack yarn build; \
     elif [ -f pnpm-lock.yaml ]; then pnpm build; \
     else npm run build; fi
 
diff --git a/docs/CICD_MULTI_STAGE_BUILD.md b/docs/CICD_MULTI_STAGE_BUILD.md
index b2bdd7a..b370e51 100644
--- a/docs/CICD_MULTI_STAGE_BUILD.md
+++ b/docs/CICD_MULTI_STAGE_BUILD.md
@@ -148,6 +148,32 @@ jobs:
   `.gitea/workflows/cicd-tests.yaml` own CI validation and checks.
 - Main CI never rebuilds the base image locally.
 
+### Runtime Boundary Enforcement
+
+The main build workflow now enforces separation between validation environments
+and deployable runtime artifacts before publishing the complete CICD image.
+
+- Dockerfile boundary check:
+  - Script: `scripts/check-dockerfile-boundaries.sh`
+  - Validates `Dockerfile.backend` and `Dockerfile.frontend` do not reference
+    CICD image paths (`cicd-base`, `CICD_BASE_IMAGE`, `Dockerfile.cicd*`) and
+    do not install disallowed CI-only tooling.
+- Deployable image purity check:
+  - Script: `scripts/verify-deployable-image-purity.sh`
+  - Builds deployable backend and frontend production images and verifies known
+    CI/development binaries are absent from final runtime artifacts.
+  - Performs profile-specific metadata checks:
+    - Backend: Python module import probes and pip metadata checks for
+      disallowed CI/development packages.
+    - Frontend: OS package metadata checks (apk/dpkg when available) and
+      development package directory detection.
+
+Workflow location:
+
+- `.gitea/workflows/docker-build-main.yaml`
+  - `Verify deployable runtime boundaries`
+  - `Build and verify deployable runtime image purity`
+
 ## Local Development
 
 ### Building Base Image
diff --git a/docs/DEPLOYABLE_RUNTIME_CONTRACT.md b/docs/DEPLOYABLE_RUNTIME_CONTRACT.md
index daa6772..64ddf00 100644
--- a/docs/DEPLOYABLE_RUNTIME_CONTRACT.md
+++ b/docs/DEPLOYABLE_RUNTIME_CONTRACT.md
@@ -145,12 +145,20 @@ Note:
    definition.
    - Covered by: "Disallowed Tooling Classes in Deployable Runtime Images".
 
-## Future Enforcement Hooks (Out of Scope for PP-58)
+## Enforcement Hooks
 
-Potential follow-up automation under epic #66:
+Current enforcement implemented in CI:
+
+- Dockerfile target boundary checks:
+  - Script: `scripts/check-dockerfile-boundaries.sh`
+  - Workflow: `.gitea/workflows/docker-build-main.yaml`
+- Deployable runtime image purity checks:
+  - Script: `scripts/verify-deployable-image-purity.sh`
+  - Workflow: `.gitea/workflows/docker-build-main.yaml`
+  - Checks include binary presence and profile-specific package metadata probes
+    to detect CI/development tooling leakage.
+
+Future follow-up automation under epic #66 may expand this with:
 
-- Policy checks validating final image layers do not include disallowed tooling
-  classes.
 - Contract tests that assert documented health/startup behavior.
-- CI checks that verify Dockerfile target boundaries remain aligned with this
-  contract.
+- Additional policy checks for drift detection and broader runtime compliance.
diff --git a/docs/DEVELOPMENT.md b/docs/DEVELOPMENT.md
index a8668d1..85a7dd1 100644
--- a/docs/DEVELOPMENT.md
+++ b/docs/DEVELOPMENT.md
@@ -34,9 +34,34 @@ When changing deployment behavior or image composition, treat
 
 Scope boundary:
 
-- This repository separates contract definition from enforcement mechanics.
-- CI workflow rewiring and test execution redesign are out of scope for PP-58
-  and belong to follow-up work under epic #66.
+- Contract definition lives in `DEPLOYABLE_RUNTIME_CONTRACT.md`.
+- CI enforcement now includes Dockerfile boundary checks and deployable image
+  purity checks in `.gitea/workflows/docker-build-main.yaml`.
+- Broader workflow redesign and deployment wiring remain out of scope for this
+  repository's runtime contract document and belong to follow-up work under
+  epic #66.
+
+## Runtime vs Validation Enforcement
+
+Deployable runtime artifacts and validation environments are intentionally
+separated.
+
+- Validation tools (lint/typecheck/test/browser tooling) belong to CICD image
+  paths (`Dockerfile.cicd-base`, `Dockerfile.cicd`) and CI validation
+  workflows.
+- Deployable runtime paths (`Dockerfile.backend`, `Dockerfile.frontend`
+  production target) must remain independent of CI-only tooling layers.
+
+Automated checks:
+
+- `scripts/check-dockerfile-boundaries.sh` validates deployable Dockerfiles do
+  not depend on CICD images or install disallowed CI-only tools.
+- `scripts/verify-deployable-image-purity.sh` inspects built deployable images
+  and fails if CI/development binaries or package metadata artifacts are
+  present.
+
+These checks run in `.gitea/workflows/docker-build-main.yaml` before publishing
+the complete CICD image.
 
 ## Quick Start
 
diff --git a/scripts/check-dockerfile-boundaries.sh b/scripts/check-dockerfile-boundaries.sh
new file mode 100644
index 0000000..96f2517
--- /dev/null
+++ b/scripts/check-dockerfile-boundaries.sh
@@ -0,0 +1,72 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "${ROOT_DIR}"
+
+backend_file="Dockerfile.backend"
+frontend_file="Dockerfile.frontend"
+
+declare -a disallowed_references=(
+  "cicd-base"
+  "CICD_BASE_IMAGE"
+  "Dockerfile.cicd"
+  "Dockerfile.cicd-base"
+  "plex-playlist-cicd"
+)
+
+declare -a disallowed_runtime_tools=(
+  "ruff"
+  "pyright"
+  "pytest"
+  "pydoclint"
+  "xdoctest"
+  "pre-commit"
+  "yamllint"
+  "toml-sort"
+  "eslint"
+  "prettier"
+  "typescript"
+  "vitest"
+  "playwright"
+)
+
+check_absent() {
+  local file="$1"
+  local token="$2"
+
+  if grep -Eiv '^[[:space:]]*#' "${file}" | grep -Eiq "${token}"; then
+    echo "❌ Found disallowed token '${token}' in ${file}" >&2
+    return 1
+  fi
+
+  return 0
+}
+
+status=0
+
+for token in "${disallowed_references[@]}"; do
+  check_absent "${backend_file}" "${token}" || status=1
+  check_absent "${frontend_file}" "${token}" || status=1
+done
+
+for token in "${disallowed_runtime_tools[@]}"; do
+  check_absent "${backend_file}" "${token}" || status=1
+  check_absent "${frontend_file}" "${token}" || status=1
+done
+
+if ! grep -Eq '^FROM[[:space:]]+python:3\.14-slim' "${backend_file}"; then
+  echo "❌ ${backend_file} must use python:3.14-slim as runtime base" >&2
+  status=1
+fi
+
+if ! grep -Eq '^FROM[[:space:]]+nginx:alpine[[:space:]]+AS[[:space:]]+production' "${frontend_file}"; then
+  echo "❌ ${frontend_file} must use nginx:alpine for production target" >&2
+  status=1
+fi
+
+if [[ "${status}" -ne 0 ]]; then
+  exit "${status}"
+fi
+
+echo "✅ Dockerfile runtime boundaries are valid"
diff --git a/scripts/verify-deployable-image-purity.sh b/scripts/verify-deployable-image-purity.sh
new file mode 100644
index 0000000..9797245
--- /dev/null
+++ b/scripts/verify-deployable-image-purity.sh
@@ -0,0 +1,268 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+usage() {
+  cat <<'USAGE'
+Usage:
+  scripts/verify-deployable-image-purity.sh --image <image-ref> --profile <backend|frontend>
+USAGE
+}
+
+image_ref=""
+profile=""
+
+while [[ $# -gt 0 ]]; do
+  case "$1" in
+    --image)
+      image_ref="${2:-}"
+      shift 2
+      ;;
+    --profile)
+      profile="${2:-}"
+      shift 2
+      ;;
+    -h|--help)
+      usage
+      exit 0
+      ;;
+    *)
+      echo "Unknown argument: $1" >&2
+      usage
+      exit 2
+      ;;
+  esac
+done
+
+if [[ -z "${image_ref}" || -z "${profile}" ]]; then
+  usage
+  exit 2
+fi
+
+case "${profile}" in
+  backend)
+    checks=(
+      ruff
+      pyright
+      pytest
+      pydoclint
+      xdoctest
+      pre-commit
+      yamllint
+      toml-sort
+      eslint
+      prettier
+      tsc
+      vitest
+      playwright
+      yarn
+      npm
+      node
+      pnpm
+    )
+    ;;
+  frontend)
+    checks=(
+      ruff
+      pyright
+      pytest
+      pydoclint
+      xdoctest
+      pre-commit
+      yamllint
+      toml-sort
+      eslint
+      prettier
+      tsc
+      vitest
+      playwright
+      uv
+      python
+      python3
+      pip
+      pip3
+      node
+      npm
+      yarn
+      pnpm
+    )
+    ;;
+  *)
+    echo "Unsupported profile: ${profile}" >&2
+    usage
+    exit 2
+    ;;
+esac
+
+tmp_file="$(mktemp)"
+trap 'rm -f "${tmp_file}"' EXIT
+
+printf '%s\n' "${checks[@]}" > "${tmp_file}"
+
+binary_violations="$(docker run --rm --entrypoint /bin/sh "${image_ref}" -c '
+set -e
+while IFS= read -r cmd; do
+  if command -v "$cmd" >/dev/null 2>&1; then
+    printf "%s\n" "$cmd"
+  fi
+done
+' < "${tmp_file}")"
+
+if [[ -n "${binary_violations}" ]]; then
+  echo "❌ Found CI/development tooling binaries in ${profile} image: ${image_ref}" >&2
+  echo "${binary_violations}" >&2
+  exit 1
+fi
+
+case "${profile}" in
+  backend)
+    backend_python_modules=(
+      pytest
+      ruff
+      pyright
+      pydoclint
+      xdoctest
+      pre_commit
+      yamllint
+      toml_sort
+      playwright
+    )
+
+    backend_python_packages=(
+      pytest
+      ruff
+      pyright
+      pydoclint
+      xdoctest
+      pre-commit
+      yamllint
+      toml-sort
+      playwright
+    )
+
+    module_violations="$(docker run --rm --entrypoint /bin/sh \
+      -e MODULES="${backend_python_modules[*]}" \
+      "${image_ref}" -c '
+set -e
+
+PYTHON_BIN=""
+if command -v python3 >/dev/null 2>&1; then
+  PYTHON_BIN="python3"
+elif command -v python >/dev/null 2>&1; then
+  PYTHON_BIN="python"
+fi
+
+if [ -z "$PYTHON_BIN" ]; then
+  echo "__missing_python_runtime__"
+  exit 0
+fi
+
+for module in ${MODULES}; do
+  if "$PYTHON_BIN" -c "import importlib.util,sys; sys.exit(0 if importlib.util.find_spec(\"$module\") else 1)" >/dev/null 2>&1; then
+    printf "%s\n" "$module"
+  fi
+done
+')"
+
+    if echo "${module_violations}" | grep -q '__missing_python_runtime__'; then
+      echo "❌ Backend deployable image is missing python runtime: ${image_ref}" >&2
+      exit 1
+    fi
+
+    if [[ -n "${module_violations}" ]]; then
+      echo "❌ Found CI/development Python modules importable in backend image: ${image_ref}" >&2
+      echo "${module_violations}" >&2
+      exit 1
+    fi
+
+    pip_violations="$(docker run --rm --entrypoint /bin/sh \
+      -e PACKAGES="${backend_python_packages[*]}" \
+      "${image_ref}" -c '
+set -e
+
+PIP_BIN=""
+if command -v pip3 >/dev/null 2>&1; then
+  PIP_BIN="pip3"
+elif command -v pip >/dev/null 2>&1; then
+  PIP_BIN="pip"
+fi
+
+if [ -z "$PIP_BIN" ]; then
+  exit 0
+fi
+
+for package in ${PACKAGES}; do
+  if "$PIP_BIN" show "$package" >/dev/null 2>&1; then
+    printf "%s\n" "$package"
+  fi
+done
+')"
+
+    if [[ -n "${pip_violations}" ]]; then
+      echo "❌ Found CI/development Python packages in backend image metadata: ${image_ref}" >&2
+      echo "${pip_violations}" >&2
+      exit 1
+    fi
+    ;;
+  frontend)
+    frontend_os_packages=(
+      nodejs
+      npm
+      yarn
+      python3
+      py3-pip
+      py3-setuptools
+    )
+
+    os_pkg_violations="$(docker run --rm --entrypoint /bin/sh \
+      -e PACKAGES="${frontend_os_packages[*]}" \
+      "${image_ref}" -c '
+set -e
+
+if command -v apk >/dev/null 2>&1; then
+  for package in ${PACKAGES}; do
+    if apk info -e "$package" >/dev/null 2>&1; then
+      printf "apk:%s\n" "$package"
+    fi
+  done
+elif command -v dpkg-query >/dev/null 2>&1; then
+  for package in ${PACKAGES}; do
+    if dpkg-query -W -f='"'"'${db:Status-Status}'"'"' "$package" 2>/dev/null | grep -q '^installed$'; then
+      printf "dpkg:%s\n" "$package"
+    fi
+  done
+fi
+')"
+
+    if [[ -n "${os_pkg_violations}" ]]; then
+      echo "❌ Found CI/development OS packages in frontend runtime image: ${image_ref}" >&2
+      echo "${os_pkg_violations}" >&2
+      exit 1
+    fi
+
+    dir_violations="$(docker run --rm --entrypoint /bin/sh "${image_ref}" -c '
+set -e
+
+check_dir_tree() {
+  local base_dir="$1"
+  [ -d "$base_dir" ] || return 0
+
+  find "$base_dir" -maxdepth 5 -type d \
+    \( -name node_modules -o -name .venv -o -name site-packages -o -name dist-packages \) \
+    2>/dev/null || true
+}
+
+check_dir_tree /app
+check_dir_tree /usr/local/lib
+check_dir_tree /usr/lib
+check_dir_tree /opt
+')"
+
+    if [[ -n "${dir_violations}" ]]; then
+      echo "❌ Found development package directories in frontend runtime image: ${image_ref}" >&2
+      echo "${dir_violations}" >&2
+      exit 1
+    fi
+    ;;
+esac
+
+echo "✅ ${profile} image is clean of disallowed CI/development tooling binaries and metadata"