diff --git a/.coveragerc b/.coveragerc
index b3fdad5f..d7546b55 100644
--- a/.coveragerc
+++ b/.coveragerc
@@ -17,7 +17,7 @@ src =
 [report]
 precision = 1
 show_missing = true
-skip_covered = false
+skip_covered = true
 fail_under = 50
 
 # Some of the patterns below were taken or adapted
@@ -36,6 +36,7 @@ exclude_lines =
     : \.\.\.(\s*#.*)?$
     ^ +\.\.\.$
     -> ['"]?NoReturn['"]?:
+    ^\s*assert_never\b
     # non-runnable code
     if __name__ == ['"]__main__['"]:$
 partial_branches =
diff --git a/AGENTS.md b/AGENTS.md
index 0c5010e9..caa236fc 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -209,7 +209,8 @@ def _coerce_to_densities(...):
 ## CI/CD Pipeline
 
 GitHub Actions runs tests on Python 3.10–3.14 across Ubuntu, macOS, and Windows.
-Codecov minimums are 98% overall and 100% diff coverage for new code.
+Codecov minimums are 100% overall and 100% diff coverage for new code.
+Intentionally-untested lines must carry an explicit `# pragma: no cover` comment.
 
 ## Notes for AI Assistants
 
diff --git a/codecov.yml b/codecov.yml
new file mode 100644
index 00000000..514a8f98
--- /dev/null
+++ b/codecov.yml
@@ -0,0 +1,15 @@
+# Codecov configuration
+# ref: https://docs.codecov.com/docs/codecov-yaml
+#
+# Note: CI only uploads the combined coverage report
+# (see the coverage-combine env in tox.ini), which omits
+# "cicd_utils/*" and "tests/*", so these targets apply
+# to the src/ridgeplot package only.
+coverage:
+  status:
+    project:
+      default:
+        target: 100%
+    patch:
+      default:
+        target: 100%
diff --git a/docs/reference/changelog.md b/docs/reference/changelog.md
index e7bf832f..807a9c98 100644
--- a/docs/reference/changelog.md
+++ b/docs/reference/changelog.md
@@ -7,6 +7,7 @@ Unreleased changes
 
 ### CI/CD
 
+- Review the coverage configuration in light of `covdefaults`, adopting its `assert_never` exclusion and `skip_covered` report setting, and raising all package coverage gates to 100% ({gh-pr}`390`)
 - Bump actions/download-artifact from 7 to 8 ({gh-pr}`368`)
 - Bump actions/upload-artifact from 6 to 7 ({gh-pr}`369`)
 - Bump sigstore/gh-action-sigstore-python from 3.2.0 to 3.3.0 ({gh-pr}`370`)
diff --git a/tox.ini b/tox.ini
index 721c6ec4..8f90a9ce 100644
--- a/tox.ini
+++ b/tox.ini
@@ -35,7 +35,7 @@ commands =
 
     pytest: pytest --no-cov {posargs}
 
-    tests-unit: pytest tests/unit --doctest-modules src {env:_COV_REPORT_XML} --cov-fail-under=95 {posargs:}
+    tests-unit: pytest tests/unit --doctest-modules src {env:_COV_REPORT_XML} --cov-fail-under=100 {posargs:}
     tests-unit: diff-cover {env:_DIFFCOVER_DFLT_ARGS} --fail-under=100
 
     tests-e2e: pytest tests/e2e --cov=cicd_utils/ridgeplot_examples {env:_COV_REPORT_XML} --cov-fail-under=74 {posargs:}
@@ -49,7 +49,7 @@ commands =
     coverage-combine: mv .coverage {env:COVERAGE_FILE}
     coverage-combine: coverage xml  --data-file={env:COVERAGE_FILE} --omit="cicd_utils/*,tests/*" -o {env:COVERAGE_XML_FILE}
     coverage-combine: coverage html --data-file={env:COVERAGE_FILE} --omit="cicd_utils/*,tests/*"
-    coverage-combine: coverage report --data-file={env:COVERAGE_FILE} --omit="cicd_utils/*,tests/*" --fail-under=98
+    coverage-combine: coverage report --data-file={env:COVERAGE_FILE} --omit="cicd_utils/*,tests/*" --fail-under=100
     coverage-combine: diff-cover {env:_DIFFCOVER_DFLT_ARGS} --fail-under=100
 
 [testenv:pre-commit-{all,quick,autoupgrade}]