diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
index 8fb222d..f7c2b51 100644
--- a/.github/workflows/coverage.yml
+++ b/.github/workflows/coverage.yml
@@ -21,13 +21,18 @@ jobs:
         run: nix develop --command uv sync --frozen
 
       # coverage.py branch measurement: https://coverage.readthedocs.io/en/7.10.7/branch.html
+      # Importable source identity: https://coverage.readthedocs.io/en/7.10.7/source.html
+      # Empty-data gate: https://coverage.readthedocs.io/en/7.10.7/commands/cmd_report.html
       # uv --with contract: https://docs.astral.sh/uv/reference/cli/#uv-run--with
+      # LLM contract: DISCOVERED -> ENCODED -> ROUNDTRIP_VERIFIED -> BENCHMARKED -> REPORTED.
+      # Coverage is descriptive code-quality evidence; it never advances benchmark
+      # lifecycle state or changes ranking eligibility.
       - name: Run branch coverage
-        run: nix develop --command uv run --frozen --with coverage==7.10.7 coverage run --branch --source=src -m pytest
+        run: nix develop --command uv run --frozen --with coverage==7.10.7 coverage run --branch --source=format_bench -m pytest
 
       - name: Write coverage reports
         run: |
-          nix develop --command uv run --frozen --with coverage==7.10.7 coverage report
+          nix develop --command uv run --frozen --with coverage==7.10.7 coverage report --fail-under=1
           nix develop --command uv run --frozen --with coverage==7.10.7 coverage xml -o coverage.xml
           nix develop --command uv run --frozen --with coverage==7.10.7 coverage html
 
diff --git a/tests/test_coverage_workflow.py b/tests/test_coverage_workflow.py
new file mode 100644
index 0000000..310a8ce
--- /dev/null
+++ b/tests/test_coverage_workflow.py
@@ -0,0 +1,15 @@
+from pathlib import Path
+
+
+WORKFLOW = Path(__file__).parents[1] / ".github/workflows/coverage.yml"
+
+
+def test_coverage_workflow_targets_imported_package_and_rejects_empty_data() -> None:
+    workflow = WORKFLOW.read_text(encoding="utf-8")
+
+    assert "--source=format_bench -m pytest" in workflow
+    assert "--source=src" not in workflow
+    assert "coverage report --fail-under=1" in workflow
+    assert workflow.index("coverage report --fail-under=1") < workflow.index(
+        "coverage xml"
+    )