diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c34bd01..054aac8 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -13,6 +13,43 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
+  repository-policy:
+    name: Repository policy
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+
+      - name: Set up repository linters
+        uses: jdx/mise-action@9e7f7633ff6f6d6048a9418a68d48f288f50eb14 # v4.2.3
+        with:
+          install_args: actionlint zizmor
+
+      - name: Lint GitHub Actions
+        run: |
+          actionlint -color
+          zizmor --min-severity medium .github/workflows
+
+  consumer-isolation:
+    name: Consumer dependency isolation
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+
+      - name: Set up Java
+        uses: actions/setup-java@03ad4de0992f5dab5e18fcb136590ce7c4a0ac95 # v5
+        with:
+          distribution: temurin
+          java-version: '21'
+
+      - name: Verify isolated consumer
+        run: ./scripts/verify-consumer-isolation.sh
+
   build:
     name: Build (Java ${{ matrix.java }})
     runs-on: ${{ matrix.os }}
diff --git a/.github/workflows/docs.yml b/.github/workflows/docs.yml
index a4fb56d..f24993d 100644
--- a/.github/workflows/docs.yml
+++ b/.github/workflows/docs.yml
@@ -26,6 +26,8 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
 
       - name: Install mdbook-lint
         shell: bash
@@ -65,6 +67,8 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
 
       - name: Check external links
         uses: lycheeverse/lychee-action@e7477775783ea5526144ba13e8db5eec57747ce8 # v2.9.0
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2f8dc30..6310bf7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,8 @@ The format is based on [Keep a Changelog], and this project adheres to [Semantic
 - Documentation checks based on `mdbook-lint` and Lychee.
 - Consumer-classpath verification for applications that install a single DATEX II model.
 - Adversarial XML tests covering DTDs, external entities, and recursive entity expansion.
+- A single contributor verification command with isolated Maven consumer checks, actionable
+  failure logs, coverage summaries, and GitHub Actions linting.
 
 ### Changed
 
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 2de09f2..8f75cbe 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -11,9 +11,14 @@ Maven wrapper pins Maven.
 
 ```bash
 mise install
-./mvnw verify
+./scripts/verify.sh
 ```
 
+The verification script checks GitHub Actions syntax and security, verifies the critical XML and
+validation modules, tests the consumer dependency graph with an isolated Maven repository, runs
+the complete Maven reactor, and prints the final coverage ratios. Its full log is written to
+`target/verification/verify.log`.
+
 Read the [architecture guide](docs/architecture.md) before changing module boundaries or adding a
 dependency.
 
diff --git a/mise.toml b/mise.toml
index da805ab..686231b 100644
--- a/mise.toml
+++ b/mise.toml
@@ -1,5 +1,7 @@
 # Developer toolchain pinned for reproducible local and CI builds.
-# Maven is provided by the committed Maven Wrapper (./mvnw), so only Java is pinned here.
-# Run `mise install` to provision Java, then `./mvnw verify`.
+# Maven is provided by the committed Maven Wrapper (./mvnw).
+# Run `mise install`, then `./scripts/verify.sh`.
 [tools]
 java = "temurin-21.0.11+10.0.LTS"
+actionlint = "1.7.12"
+zizmor = "1.28.0"
diff --git a/scripts/verify-consumer-isolation.sh b/scripts/verify-consumer-isolation.sh
new file mode 100755
index 0000000..8fd7372
--- /dev/null
+++ b/scripts/verify-consumer-isolation.sh
@@ -0,0 +1,46 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+project_root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+temporary_root="$(mktemp -d "${TMPDIR:-/tmp}/datex4j-consumer-isolation.XXXXXX")"
+local_repository="${temporary_root}/repository"
+dependency_tree="${temporary_root}/dependency-tree.txt"
+
+cleanup() {
+  rm -rf "${temporary_root}"
+}
+trap cleanup EXIT
+
+cd "${project_root}"
+
+./mvnw --batch-mode --no-transfer-progress \
+  -Dmaven.repo.local="${local_repository}" \
+  -DskipTests \
+  -Djacoco.skip=true \
+  -pl datex4j-xml,datex4j-json,datex4j-model-v3_7 \
+  -am \
+  install
+
+./mvnw --batch-mode --no-transfer-progress \
+  -Dmaven.repo.local="${local_repository}" \
+  -f datex4j-consumer-tests/pom.xml \
+  -Dscope=test \
+  -DoutputType=text \
+  -DoutputFile="${dependency_tree}" \
+  dependency:tree
+
+if ! grep -Eq 'dev\.juherr\.datex4j:datex4j-model-v3_7:' "${dependency_tree}"; then
+  echo "Expected datex4j-model-v3_7 is missing from the consumer dependency tree." >&2
+  exit 1
+fi
+
+if grep -Eq \
+  'dev\.juherr\.datex4j:(datex4j-model:|datex4j-model-v(2_[0-3]|3_[0-6]):)' \
+  "${dependency_tree}"; then
+  echo "Unexpected generated model dependency found:" >&2
+  grep -E 'dev\.juherr\.datex4j:(datex4j-model:|datex4j-model-v[23]_)' \
+    "${dependency_tree}" >&2
+  exit 1
+fi
+
+echo "Consumer isolation verified: only datex4j-model-v3_7 is installed."
diff --git a/scripts/verify.sh b/scripts/verify.sh
new file mode 100755
index 0000000..616b266
--- /dev/null
+++ b/scripts/verify.sh
@@ -0,0 +1,61 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+project_root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+report_directory="${project_root}/target/verification"
+log_file="${report_directory}/verify.log"
+
+mkdir -p "${report_directory}"
+: >"${log_file}"
+
+run_logged() {
+  local description="$1"
+  shift
+  echo "==> ${description}" | tee -a "${log_file}"
+  if "$@" 2>&1 | tee -a "${log_file}"; then
+    return
+  fi
+  echo "Verification failed during: ${description}" >&2
+  echo "Last 80 log lines:" >&2
+  tail -n 80 "${log_file}" >&2
+  exit 1
+}
+
+print_coverage() {
+  local module="$1"
+  local report="${project_root}/${module}/target/site/jacoco/jacoco.csv"
+  if [[ ! -f "${report}" ]]; then
+    echo "${module}: no JaCoCo report"
+    return
+  fi
+  awk -F, -v module="${module}" \
+    'NR > 1 { missed += $8; covered += $9 }
+     END {
+       total = missed + covered;
+       if (total == 0) {
+         printf "%s line coverage: 0/0 (0.0%%)\n", module;
+         exit;
+       }
+       printf "%s line coverage: %d/%d (%.1f%%)\n", module, covered, total, 100 * covered / total
+     }' \
+    "${report}"
+}
+
+cd "${project_root}"
+
+run_logged "GitHub Actions syntax" mise exec -- actionlint -color
+run_logged \
+  "GitHub Actions security" \
+  mise exec -- zizmor --min-severity medium .github/workflows
+run_logged \
+  "critical XML and validation modules" \
+  ./mvnw --batch-mode --no-transfer-progress \
+  -pl datex4j-xml,datex4j-validation -am verify
+run_logged "isolated consumer dependency graph" ./scripts/verify-consumer-isolation.sh
+run_logged \
+  "full Maven reactor" \
+  ./mvnw --batch-mode --no-transfer-progress verify
+
+print_coverage datex4j-xml | tee -a "${log_file}"
+print_coverage datex4j-validation | tee -a "${log_file}"
+echo "Verification succeeded. Full log: ${log_file}"