diff --git a/.github/workflows/valid-style.yml b/.github/workflows/valid-style.yml
index 3e15eb1240a..91ab7339046 100644
--- a/.github/workflows/valid-style.yml
+++ b/.github/workflows/valid-style.yml
@@ -13,8 +13,7 @@ concurrency:
 
 
 jobs:
-  # Validate that the code can be run on all the Python versions
-  # supported by Spack
+  # Validate that the code can be run on all the Python versions supported by Spack
   validate:
     runs-on: ubuntu-latest
     steps:
@@ -87,6 +86,7 @@ jobs:
           spack -d bootstrap now --dev
           spack -d style -t black
           spack unit-test -V
+  # Check we don't make the situation with circular imports worse
   import-check:
     runs-on: ubuntu-latest
     steps:
@@ -146,3 +146,21 @@ jobs:
         else
           printf '\033[1;32mImport check passed: %s <= %s\033[0m\n' "$edges_after" "$edges_before"
         fi
+
+  # Further style checks from pylint
+  pylint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
+        with:
+          fetch-depth: 0
+      - uses: actions/setup-python@0b93645e9fea7318ecaed2b359559ac225c90a2b
+        with:
+          python-version: '3.13'
+          cache: 'pip'
+      - name: Install Python packages
+        run: |
+          pip install --upgrade pip setuptools pylint
+      - name: Pylint (Spack Core)
+        run: |
+          pylint -j 4 --disable=all --enable=unspecified-encoding --ignore-paths=lib/spack/external lib
diff --git a/lib/spack/llnl/util/tty/color.py b/lib/spack/llnl/util/tty/color.py
index 51a5a1b5b1e..edba41dc55c 100644
--- a/lib/spack/llnl/util/tty/color.py
+++ b/lib/spack/llnl/util/tty/color.py
@@ -161,7 +161,7 @@ def _err_check(result, func, args):
             )
             # Use conout$ here to handle a redirectired stdout/get active console associated
             # with spack
-            with open(r"\\.\CONOUT$", "w") as conout:
+            with open(r"\\.\CONOUT$", "w", encoding="utf-8") as conout:
                 # Link above would use kernel32.GetStdHandle(-11) however this would not handle
                 # a redirected stdout appropriately, so we always refer to the current CONSOLE out
                 # which is defined as conout$ on Windows.
diff --git a/lib/spack/llnl/util/tty/log.py b/lib/spack/llnl/util/tty/log.py
index 612d9ff380e..25e17537013 100644
--- a/lib/spack/llnl/util/tty/log.py
+++ b/lib/spack/llnl/util/tty/log.py
@@ -762,7 +762,7 @@ def __enter__(self):
             self.reader = open(self.logfile, mode="rb+")
 
             # Dup stdout so we can still write to it after redirection
-            self.echo_writer = open(os.dup(sys.stdout.fileno()), "w")
+            self.echo_writer = open(os.dup(sys.stdout.fileno()), "w", encoding=sys.stdout.encoding)
             # Redirect stdout and stderr to write to logfile
             self.stderr.redirect_stream(self.writer.fileno())
             self.stdout.redirect_stream(self.writer.fileno())
diff --git a/lib/spack/spack/test/llnl/util/filesystem.py b/lib/spack/spack/test/llnl/util/filesystem.py
index 4b05c0ea22e..d6609b18d56 100644
--- a/lib/spack/spack/test/llnl/util/filesystem.py
+++ b/lib/spack/spack/test/llnl/util/filesystem.py
@@ -506,9 +506,7 @@ def test_filter_files_with_different_encodings(regex, replacement, filename, tmp
     # This should not raise exceptions
     fs.filter_file(regex, replacement, target_file, **keyword_args)
     # Check the strings have been replaced
-    extra_kwargs = {"errors": "surrogateescape"}
-
-    with open(target_file, mode="r", **extra_kwargs) as f:
+    with open(target_file, mode="r", encoding="utf-8", errors="surrogateescape") as f:
         assert replacement in f.read()
 
 
@@ -558,9 +556,7 @@ def test_filter_files_multiple(tmpdir):
     fs.filter_file(r"\<string.h\>", "<unistd.h>", target_file)
     fs.filter_file(r"\<stdio.h\>", "<unistd.h>", target_file)
     # Check the strings have been replaced
-    extra_kwargs = {"errors": "surrogateescape"}
-
-    with open(target_file, mode="r", **extra_kwargs) as f:
+    with open(target_file, mode="r", encoding="utf-8", errors="surrogateescape") as f:
         assert "<malloc.h>" not in f.read()
         assert "<string.h>" not in f.read()
         assert "<stdio.h>" not in f.read()
diff --git a/lib/spack/spack/test/modules/conftest.py b/lib/spack/spack/test/modules/conftest.py
index 1feee7adcba..1a490548d37 100644
--- a/lib/spack/spack/test/modules/conftest.py
+++ b/lib/spack/spack/test/modules/conftest.py
@@ -23,7 +23,7 @@ def _impl(spec_like, module_set_name="default", explicit=True):
         generator = writer_cls(spec, module_set_name, explicit)
         generator.write(overwrite=True)
         written_module = pathlib.Path(generator.layout.filename)
-        content = written_module.read_text().splitlines()
+        content = written_module.read_text(encoding="utf-8").splitlines()
         generator.remove()
         return content
 
diff --git a/lib/spack/spack/util/executable.py b/lib/spack/spack/util/executable.py
index 35238059b28..7bbd119cbeb 100644
--- a/lib/spack/spack/util/executable.py
+++ b/lib/spack/spack/util/executable.py
@@ -203,7 +203,7 @@ def process_cmd_output(out, err):
 
         def streamify(arg, mode):
             if isinstance(arg, str):
-                return open(arg, mode), True
+                return open(arg, mode), True  # pylint: disable=unspecified-encoding
             elif arg in (str, str.split):
                 return subprocess.PIPE, False
             else: