diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 0a6be58e..08a4abb9 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -17,9 +17,9 @@ build_docs:
     paths:
       - _build
   script:
-      - apt-get -y install python3-pip python3-sphinx
-      - pip3 install recommonmark
-      - ./doc/build.sh _build
+    - apt-get -y install python3-pip python3-sphinx
+    - pip3 install recommonmark
+    - ./doc/build.sh _build
   except:
     variables:
       - $PKG_ONLY == "1"
@@ -42,33 +42,37 @@ build_deb:
   stage: build
   artifacts:
     paths:
-      - "*.deb"
+      - '*.deb'
   script:
-      - rm -f ../*.deb
-      - apt-get -y build-dep .
-      - apt-get -y install devscripts
-      - REV=$(git log -1 --format=%h)
-      - VER=$(dpkg-parsechangelog -SVersion)
-      - 'DEBFULLNAME="Librem5 CI" EMAIL="librem5-builds@lists.community.puri.sm" dch -v"$VER+librem5ci$CI_PIPELINE_ID.$REV" "$MSG"'
-      - debuild -i -us -uc -b
-      - cp ../*.deb .
+    - rm -f ../*.deb
+    - apt-get -y build-dep .
+    - apt-get -y install devscripts
+    - REV=$(git log -1 --format=%h)
+    - VER=$(dpkg-parsechangelog -SVersion)
+    - DEBFULLNAME="Librem5 CI"
+    - EMAIL="librem5-builds@lists.community.puri.sm"
+    - dch -v"$VER+librem5ci$CI_PIPELINE_ID.$REV" "$MSG"
+    - debuild -i -us -uc -b
+    - cp ../*.deb .
 
 build_deb:arm64:
   tags:
-      - aarch64
+    - aarch64
   stage: build
   artifacts:
     paths:
-      - "*.deb"
+      - '*.deb'
   script:
-      - rm -f ../*.deb
-      - apt-get -y build-dep .
-      - apt-get -y install devscripts
-      - REV=$(git log -1 --format=%h)
-      - VER=$(dpkg-parsechangelog -SVersion)
-      - 'DEBFULLNAME="Librem5 CI" EMAIL="librem5-builds@lists.community.puri.sm" dch -v"$VER+librem5ci$CI_PIPELINE_ID.$REV" "$MSG"'
-      - debuild -i -us -uc -b
-      - cp ../*.deb .
+    - rm -f ../*.deb
+    - apt-get -y build-dep .
+    - apt-get -y install devscripts
+    - REV=$(git log -1 --format=%h)
+    - VER=$(dpkg-parsechangelog -SVersion)
+    - DEBFULLNAME="Librem5 CI"
+    - EMAIL="librem5-builds@lists.community.puri.sm"
+    - dch -v"$VER+librem5ci$CI_PIPELINE_ID.$REV" "$MSG"
+    - debuild -i -us -uc -b
+    - cp ../*.deb .
 
 test_lintian:
   stage: test
@@ -89,7 +93,17 @@ test:
     - apt-get -y build-dep .
     - apt-get -y install clang-tidy
     - ninja -C _build test
-    - tools/style-check _build
+    - tools/style-check_build _build
+  except:
+    variables:
+      - $PKG_ONLY == "1"
+
+test_style:
+  stage: test
+  needs: []
+  script:
+    - apt-get -y build-dep .
+    - tools/style-check_source
   except:
     variables:
       - $PKG_ONLY == "1"
diff --git a/debian/control b/debian/control
index b91f5d99..149dc343 100644
--- a/debian/control
+++ b/debian/control
@@ -27,6 +27,7 @@ Build-Depends:
  libwayland-dev (>= 1.16),
  lsb-release,
  python3,
+ python3-ruamel.yaml,
  rustc,
  wayland-protocols (>= 1.14),
 Standards-Version: 4.1.3
diff --git a/doc/hacking.md b/doc/hacking.md
index 4ce40ff5..6d3feca2 100644
--- a/doc/hacking.md
+++ b/doc/hacking.md
@@ -120,6 +120,16 @@ User interface modules should:
 
 ### Style
 
+Note that some portions, like the .gitlab-ci.yml file have accummulated enough style/whitespace conflicts that an enforced style checker is now applied.
+
+To fix your contributions before submitting a change, use:
+
+```
+./tools/style-check_source --apply
+```
+
+* * *
+
 Code submitted should roughly match the style of surrounding code. Things that will *not* be accepted are ones that often lead to errors:
 
 - skipping brackets `{}` after every `if()`, `else`, and similar ([SCI CERT C: EXP19-C](https://wiki.sei.cmu.edu/confluence/display/c/EXP19-C.+Use+braces+for+the+body+of+an+if%2C+for%2C+or+while+statement))
diff --git a/tools/style-check b/tools/style-check_build
similarity index 75%
rename from tools/style-check
rename to tools/style-check_build
index 24c6dc81..29ed4167 100755
--- a/tools/style-check
+++ b/tools/style-check_build
@@ -1,13 +1,15 @@
 #!/bin/sh
 
+# Enforces style check for the C parts of the project.
+
 if [ -z "$1" ]; then
-    echo "Please pass directory to check."
+    echo "Please pass build directory to check."
     exit 1
 fi
 
 cd "$1"
+
 clang-tidy --checks=-clang-diagnostic-missing-braces,readability-braces-around-statements, \
            --warnings-as-errors=readability-braces-around-statements \
            -extra-arg=-Wno-unknown-warning-option \
            ../src/*.c ../eek/*.c ../eekboard/*.c
-
diff --git a/tools/style-check_source b/tools/style-check_source
new file mode 100755
index 00000000..7a0f76ab
--- /dev/null
+++ b/tools/style-check_source
@@ -0,0 +1,12 @@
+#!/bin/sh
+
+set -e
+
+# Enforces style check for the project.
+THIS=$(realpath $0)
+TOOLS=$(dirname $THIS)
+cd $TOOLS/..
+
+# The CI file seems to be touched regularly, and causing problems often,
+# unlike layout files.
+./tools/yamlfmt ./.gitlab-ci.yml $1
diff --git a/tools/yamlfmt b/tools/yamlfmt
new file mode 100755
index 00000000..0aef3523
--- /dev/null
+++ b/tools/yamlfmt
@@ -0,0 +1,36 @@
+#!/usr/bin/env python3
+
+"""Checks YAML files for correct formatting.
+Usage: yamlfmt.py [--apply] file.yaml
+"""
+
+import ruamel.yaml
+import sys
+
+args = sys.argv[:]
+try:
+    args.remove('--apply')
+    want_apply = True
+except ValueError:
+    want_apply = False
+
+path = args[1]
+
+with open(path) as f:
+    contents = f.read()
+    yml = ruamel.yaml.round_trip_load(contents)
+    formatted = ruamel.yaml.round_trip_dump(yml, block_seq_indent=2)
+    well_formatted = formatted == contents
+        
+if not well_formatted:
+    print('The yaml file is not correctly formatted:', path)
+    if want_apply:
+        print('Correcting', path)
+        with open(path, 'w') as f:
+            f.write(formatted)
+    else:
+        print('Please use the following correction:')
+        print('----------corrected', path)
+        print(formatted)
+        print('----------end corrected', path)
+        sys.exit(1)