diff --git a/.gitlab/workflows/ci.yml b/.gitlab/workflows/ci.yml
index 10a3fa7c..0763cdff 100644
--- a/.gitlab/workflows/ci.yml
+++ b/.gitlab/workflows/ci.yml
@@ -11,7 +11,7 @@ ci:
       files:
         - pdm.lock
       prefix: venv-${PYTHON_VERSION}
-  coverage: /(?i)total.*? (100(?:\.0+)?\%|[1-9]?\d(?:\.\d+)?\%)$/
+  coverage: /TOTAL.*? (100(?:\.0+)?\%\|[1-9]?\d(?:\.\d+)?\%)$/
   image: ${CI_REGISTRY_IMAGE}/dev:py${PYTHON_VERSION}
   interruptible: true
   parallel:
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 03c05232..a87d40d5 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -88,6 +88,18 @@ repos:
         language: python
         types:
           - text
+      - id: check-jsonschema
+        name: check-jsonschema
+        entry: make check-jsonschema
+        language: python
+        files: (?x)^(
+          \.github/workflows/[^/]+|
+          \.gitlab-ci\.yml|
+          \.gitlab/workflows/[^/]+|
+          \.readthedocs\.yaml|
+          \.renovaterc\.json
+          )$
+        pass_filenames: false
       - id: forbidden-files
         name: forbidden files
         entry: found Copier update rejection files; review them and remove them
diff --git a/.renovaterc.json b/.renovaterc.json
index 0bdf670b..6571049d 100644
--- a/.renovaterc.json
+++ b/.renovaterc.json
@@ -147,7 +147,7 @@
             ],
             "postUpgradeTasks": {
                 "commands": [
-                    "find template -type f -regex 'template/.*\.github.*/workflows/.*' -exec sed -i 's|{{{depName}}}-{{{currentValue}}}|{{{depName}}}-{{{newValue}}}|g' {} +"
+                    "find template -type f -regex 'template/.*\\.github.*/workflows/.*' -exec sed -i 's|{{{depName}}}-{{{currentValue}}}|{{{depName}}}-{{{newValue}}}|g' {} +"
                 ]
             }
         },
diff --git a/Makefile b/Makefile
index 1cad7932..96da9af6 100644
--- a/Makefile
+++ b/Makefile
@@ -56,6 +56,7 @@ dev:
 
 # Install standalone tools
 prerequisites:
+	pipx install --force check-jsonschema==0.29.4
 	pipx install --force codespell[toml]==2.3.0
 	pipx install --force pdm==2.20.1
 	pipx install --force pre-commit==4.0.1
@@ -87,8 +88,15 @@ pyproject-fmt:
 codespell:
 	codespell
 
+# Check jsonschema with check-jsonschema.
+check-jsonschema:
+	check-jsonschema --builtin-schema vendor.github-workflows .github/workflows/*.yml
+	check-jsonschema --builtin-schema vendor.gitlab-ci --data-transform gitlab-ci .gitlab-ci.yml .gitlab/workflows/*.yml
+	check-jsonschema --builtin-schema vendor.readthedocs .readthedocs.yaml
+	check-jsonschema --builtin-schema vendor.renovate .renovaterc.json
+
 # Check lint with all linters.
-lint: mypy ruff ruff-format pyproject-fmt codespell
+lint: mypy ruff ruff-format pyproject-fmt codespell check-jsonschema
 
 # Run pre-commit with autofix against all files.
 pre-commit:
diff --git a/template/.pre-commit-config.yaml.jinja b/template/.pre-commit-config.yaml.jinja
index e43a7506..19cb18f5 100644
--- a/template/.pre-commit-config.yaml.jinja
+++ b/template/.pre-commit-config.yaml.jinja
@@ -91,6 +91,18 @@ repos:
         language: python
         types:
           - text
+      - id: check-jsonschema
+        name: check-jsonschema
+        entry: make check-jsonschema
+        language: python
+        files: (?x)^(
+          \.github/workflows/[^/]+|
+          \.gitlab-ci\.yml|
+          \.gitlab/workflows/[^/]+|
+          \.readthedocs\.yaml|
+          \.renovaterc\.json
+          )$
+        pass_filenames: false
       - id: forbidden-files
         name: forbidden files
         entry: found Copier update rejection files; review them and remove them
diff --git a/template/.renovaterc.json.jinja b/template/.renovaterc.json.jinja
index 4d13ca99..3ba8481e 100644
--- a/template/.renovaterc.json.jinja
+++ b/template/.renovaterc.json.jinja
@@ -161,7 +161,7 @@
             ],
             "postUpgradeTasks": {
                 "commands": [
-                    "find template -type f -regex 'template/.*\.github.*/workflows/.*' -exec sed -i {{ '\'s|{{{depName}}}-{{{currentValue}}}|{{{depName}}}-{{{newValue}}}|g\' {} +' }}"
+                    "find template -type f -regex 'template/.*\\.github.*/workflows/.*' -exec sed -i {{ '\'s|{{{depName}}}-{{{currentValue}}}|{{{depName}}}-{{{newValue}}}|g\' {} +' }}"
                 ]
             }
         },
diff --git a/template/Makefile.jinja b/template/Makefile.jinja
index e3390042..521a6351 100644
--- a/template/Makefile.jinja
+++ b/template/Makefile.jinja
@@ -58,6 +58,7 @@ dev:
 
 # Install standalone tools
 prerequisites:
+	pipx install --force check-jsonschema==0.29.4
 	pipx install --force codespell[toml]==2.3.0
 	pipx install --force pdm==2.20.1
 	pipx install --force pre-commit==4.0.1
@@ -89,8 +90,19 @@ pyproject-fmt:
 codespell:
 	codespell
 
+# Check jsonschema with check-jsonschema.
+check-jsonschema:
+[%- if repo_platform == "github" %]
+	check-jsonschema --builtin-schema vendor.github-workflows .github/workflows/*.yml
+[%- endif %]
+[%- if repo_platform == 'gitlab' or repo_platform == 'gitlab-self-managed' or project_name == "Serious Scaffold Python" %]
+	check-jsonschema --builtin-schema vendor.gitlab-ci --data-transform gitlab-ci .gitlab-ci.yml .gitlab/workflows/*.yml
+[%- endif %]
+	check-jsonschema --builtin-schema vendor.readthedocs .readthedocs.yaml
+	check-jsonschema --builtin-schema vendor.renovate .renovaterc.json
+
 # Check lint with all linters.
-lint: mypy ruff ruff-format pyproject-fmt codespell
+lint: mypy ruff ruff-format pyproject-fmt codespell check-jsonschema
 
 # Run pre-commit with autofix against all files.
 pre-commit:
diff --git a/template/[% if repo_platform == 'gitlab' or repo_platform == 'gitlab-self-managed' %].gitlab[% endif %]/workflows/ci.yml.jinja b/template/[% if repo_platform == 'gitlab' or repo_platform == 'gitlab-self-managed' %].gitlab[% endif %]/workflows/ci.yml.jinja
index e10707e4..33c85a2b 100644
--- a/template/[% if repo_platform == 'gitlab' or repo_platform == 'gitlab-self-managed' %].gitlab[% endif %]/workflows/ci.yml.jinja	
+++ b/template/[% if repo_platform == 'gitlab' or repo_platform == 'gitlab-self-managed' %].gitlab[% endif %]/workflows/ci.yml.jinja	
@@ -12,7 +12,7 @@ ci:
       files:
         - pdm.lock
       prefix: venv-${PYTHON_VERSION}
-  coverage: /(?i)total.*? (100(?:\.0+)?\%|[1-9]?\d(?:\.\d+)?\%)$/
+  coverage: /TOTAL.*? (100(?:\.0+)?\%\|[1-9]?\d(?:\.\d+)?\%)$/
   image: ${CI_REGISTRY_IMAGE}/dev:py${PYTHON_VERSION}
   interruptible: true
   parallel: