diff --git a/.github/workflows/author-testing.yml b/.github/workflows/author-testing.yml
index ef18681..a826301 100644
--- a/.github/workflows/author-testing.yml
+++ b/.github/workflows/author-testing.yml
@@ -3,7 +3,7 @@ name: author-testing
 on:
   push:
     branches:
-      - "*"
+      - "main"
     tags-ignore:
       - "*"
   pull_request:
@@ -17,26 +17,16 @@ jobs:
       AUTHOR_TESTING: 1
       AUTOMATED_TESTING: 1
       RELEASE_TESTING: 1
-      PERL_CARTON_PATH: $GITHUB_WORKSPACE/local
-
-    strategy:
-      fail-fast: false
-      matrix:
-        perl-version:
-          - "5.30"
 
     container:
-      image: perldocker/perl-tester:${{ matrix.perl-version }}
+      image: perldocker/perl-tester:5.42
 
     steps:
-      - uses: actions/checkout@v1
-      - name: perl -V
-        run: perl -V
+      - uses: actions/checkout@v6
+      - run: perl -V
       - name: Install Author Dependencies
         run: dzil authordeps | cpm install -g --show-build-log-on-failure -
       - name: Install Dependencies
-        run: dzil listdeps | cpanm
-        # cannot use cpm due to https://github.com/skaji/cpm/issues/161
-        #run: dzil listdeps | cpm install -g --show-build-log-on-failure -
+        run: dzil listdeps | cpm install -g --show-build-log-on-failure -
       - name: dzil test
         run: dzil test
diff --git a/.github/workflows/testsuite.yml b/.github/workflows/testsuite.yml
index 9b4e054..8af84cc 100644
--- a/.github/workflows/testsuite.yml
+++ b/.github/workflows/testsuite.yml
@@ -3,7 +3,7 @@ name: linux
 on:
   push:
     branches:
-      - "*"
+      - "main"
     tags-ignore:
       - "*"
   pull_request:
@@ -21,7 +21,7 @@ jobs:
       PERL_CARTON_PATH: $GITHUB_WORKSPACE/local
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - run: perl -V
       - name: Install Dependencies
         uses: perl-actions/install-with-cpm@v1
@@ -66,7 +66,7 @@ jobs:
     container: perldocker/perl-tester:${{ matrix.perl-version }}
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - run: perl -V
       - name: Install Dependencies
         run: cpm install -g --show-build-log-on-failure
diff --git a/.gitignore b/.gitignore
index d2e49e2..b22983e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -13,3 +13,4 @@ Makefile.old
 MANIFEST.bak
 Overload-FileCheck-*
 .build
+local/
diff --git a/CLAUDE.md b/CLAUDE.md
new file mode 100644
index 0000000..7a81b91
--- /dev/null
+++ b/CLAUDE.md
@@ -0,0 +1,52 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+Overload::FileCheck is a Perl XS module that hooks into Perl's OP dispatch mechanism to mock file check operators (-e, -f, -d, -s, etc.) and stat/lstat at the interpreter level. Designed for unit testing scenarios where you need to simulate filesystem conditions without real files.
+
+## Build & Test Commands
+
+```bash
+# Build (compiles XS/C code)
+perl Makefile.PL && make
+
+# Run full test suite
+make test
+
+# Run a single test
+prove -lv t/02_basic-mock.t
+
+# Author testing via Dist::Zilla
+dzil test
+
+# Build a release
+dzil build
+```
+
+Makefile.PL is auto-generated from dist.ini — edit dist.ini for build configuration, not Makefile.PL directly.
+
+## Architecture
+
+### Two-layer design
+
+**Perl layer** (`lib/Overload/FileCheck.pm`): Public API — `mock_file_check`, `mock_stat`, `mock_lstat`, `mock_all_file_checks`, `mock_all_from_stat`, and their `unmock_*` counterparts. Manages the mapping from operator names (e.g., '-e') to Perl OP types (e.g., `OP_FTIS`). Provides export groups `:check` (return value constants), `:stat` (stat index constants and helpers like `stat_as_file()`), and `:all`.
+
+**XS layer** (`FileCheck.xs` + `FileCheck.h`): Replaces Perl's default `pp_*` OP handlers with custom ones that call back into Perl. Three handler types: `pp_overload_ft_yes_no` (boolean ops like -e, -f), `pp_overload_ft_int`/`pp_overload_ft_nv` (numeric ops like -s, -M), and `pp_overload_stat` (stat/lstat). `FileCheck.h` contains compatibility macros for Perl 5.14 vs 5.15+ internal API differences.
+
+### Return value protocol
+
+Mock callbacks return: `CHECK_IS_TRUE` (1), `CHECK_IS_FALSE` (0), or `FALLBACK_TO_REAL_OP` (-1) for boolean ops. Numeric ops (-s, -M, -C, -A) return the actual value. Stat mocks return an arrayref of 13 elements (or empty arrayref for "file not found").
+
+### Test structure
+
+Tests in `t/` use Test2 framework. Many test files for individual operators (test-e.t, test-f.t, etc.) are symlinks to template files (`test-true-false.t` for boolean ops, `test-integer.t` for numeric ops) — the test determines which operator to exercise based on its own filename.
+
+## Key Conventions
+
+- Minimum Perl version: **5.010** (enforced in dist.ini and CI)
+- CI tests across Perl 5.10 through latest dev release
+- Operators accepted with or without dash: `'-e'` and `'e'` are equivalent
+- Code style: PerlTidy with 2-space indent (see `tidyall.ini`), PerlCritic severity 3
+- Distribution managed with **Dist::Zilla** (`dist.ini`); `[@Git]` plugin handles version tagging and push
diff --git a/Changes b/Changes
index 5e0ecf4..1dd1beb 100644
--- a/Changes
+++ b/Changes
@@ -2,6 +2,11 @@ Revision history for Overload-FileCheck
 
 {{$NEXT}}
 
+0.014     2026-02-22 10:19:05-07:00 America/Denver
+
+- fix: prevent filehandle reference leak in $_last_call_for
+- fix: spelling typos
+
 0.013     2022-02-23 08:36:12-07:00 America/Denver
 
 - Fix a PL_statcache bug when checking: -l $f || -e _
diff --git a/Makefile.PL b/Makefile.PL
index c8afb4d..85dd29f 100644
--- a/Makefile.PL
+++ b/Makefile.PL
@@ -1,4 +1,4 @@
-# This file was automatically generated by Dist::Zilla::Plugin::MakeMaker v6.031.
+# This file was automatically generated by Dist::Zilla::Plugin::MakeMaker v6.033.
 use strict;
 use warnings;
 
diff --git a/README.md b/README.md
index 376e62a..6ce7056 100644
--- a/README.md
+++ b/README.md
@@ -20,9 +20,6 @@ By using mock\_all\_file\_checks you can set a hook function to reply any -X che
 use strict;
 use warnings;
 
-use strict;
-use warnings;
-
 use Test::More;
 use Overload::FileCheck q{:all};
 
@@ -755,7 +752,7 @@ Nicolas R <atoomic@cpan.org>
 
 # COPYRIGHT AND LICENSE
 
-This software is copyright (c) 2022 by cPanel, L.L.C.
+This software is copyright (c) 2026 by cPanel, L.L.C.
 
 This is free software; you can redistribute it and/or modify it under
 the same terms as the Perl 5 programming language system itself.
diff --git a/dist.ini b/dist.ini
index 57380a6..3354452 100644
--- a/dist.ini
+++ b/dist.ini
@@ -2,7 +2,7 @@ name    = Overload-FileCheck
 author  = Nicolas R <atoomic@cpan.org>
 license = Perl_5
 copyright_holder = cPanel, L.L.C.
-copyright_year   = 2022
+copyright_year   = 2026
 
 ;[PPPort]
 
@@ -80,7 +80,9 @@ run = git status --porcelain | grep 'M Makefile.PL' && git commit -m 'Makefile.P
 
 [GatherDir]
 exclude_filename = Makefile.PL
+exclude_filename = CLAUDE.md
 ;exclude_filename = ppport.h
+exclude_match    = ^local/
 
 ; -- static meta-information
 [MetaResources]
diff --git a/examples/synopsis.pl b/examples/synopsis.pl
index 77f0f84..a014720 100644
--- a/examples/synopsis.pl
+++ b/examples/synopsis.pl
@@ -3,9 +3,6 @@
 use strict;
 use warnings;
 
-use strict;
-use warnings;
-
 use Test::More;
 use Overload::FileCheck q{:all};
 
diff --git a/lib/Overload/FileCheck.pm b/lib/Overload/FileCheck.pm
index 51bf9d8..654e4ba 100644
--- a/lib/Overload/FileCheck.pm
+++ b/lib/Overload/FileCheck.pm
@@ -584,7 +584,10 @@ sub _check {
 
     $file = $_last_call_for if !defined $file && defined $_last_call_for && !defined $_current_mocks->{ $MAP_FC_OP{'stat'} };
     my ( $out, @extra ) = $_current_mocks->{$optype}->($file);
-    $_last_call_for = $file;
+    # Only cache string filenames, not filehandle references.
+    # Storing a ref here prevents the filehandle from being garbage collected,
+    # causing resource leaks (e.g. sockets staying open). See GH #179.
+    $_last_call_for = ref($file) ? undef : $file;
 
     # FIXME return undef when not defined out
 
@@ -757,11 +760,11 @@ sub _stat_for {
     );
 
     foreach my $k ( keys %$opts ) {
-        $k = lc($k);
-        $k =~ s{^st_}{};
-        next unless defined $name2ix{$k};
+        my $name = lc($k);
+        $name =~ s{^st_}{};
+        next unless defined $name2ix{$name};
 
-        $stat[ $name2ix{$k} ] = $opts->{$k};
+        $stat[ $name2ix{$name} ] = $opts->{$k};
     }
 
     return \@stat;
diff --git a/t/fh-ref-leak.t b/t/fh-ref-leak.t
new file mode 100644
index 0000000..98e5e58
--- /dev/null
+++ b/t/fh-ref-leak.t
@@ -0,0 +1,66 @@
+#!/usr/bin/perl
+
+# Test that file check operators do not retain references to filehandles
+# passed as arguments. This prevents garbage collection of the filehandle,
+# which can cause resource leaks (e.g. sockets staying open).
+#
+# See: https://github.com/cpanel/Test-MockFile/issues/179
+
+use strict;
+use warnings;
+
+use Test2::Bundle::Extended;
+use Test2::Tools::Explain;
+
+use Scalar::Util qw(weaken);
+use Overload::FileCheck -from_stat => \&my_stat, qw{:check};
+
+sub my_stat {
+    my ( $stat_or_lstat, $f ) = @_;
+    return FALLBACK_TO_REAL_OP();
+}
+
+# Test that filehandle references are not retained by $_last_call_for
+{
+    my $weak_ref;
+
+    {
+        open my $fh, '<', '/dev/null' or die "Cannot open /dev/null: $!";
+        $weak_ref = $fh;
+        weaken($weak_ref);
+
+        ok( defined $weak_ref, "weak ref is defined before scope exit" );
+
+        # Trigger a file check on the filehandle — this used to store $fh
+        # in $_last_call_for, preventing garbage collection.
+        no warnings;
+        -f $fh;
+    }
+
+    ok( !defined $weak_ref, "filehandle is garbage collected after -f check (no ref leak)" );
+}
+
+# Test with -S (the operator from the original bug report)
+{
+    my $weak_ref;
+
+    {
+        open my $fh, '<', '/dev/null' or die "Cannot open /dev/null: $!";
+        $weak_ref = $fh;
+        weaken($weak_ref);
+
+        no warnings;
+        -S $fh;
+    }
+
+    ok( !defined $weak_ref, "filehandle is garbage collected after -S check (no ref leak)" );
+}
+
+# Test that string filenames still work for _ caching (no regression)
+{
+    no warnings;
+    ok( -f $0,  "-f \$0 works" );
+    ok( -e _,   "-e _ works after -f on string filename" );
+}
+
+done_testing;
diff --git a/t/stat-helpers.t b/t/stat-helpers.t
index b38f660..9e657fa 100644
--- a/t/stat-helpers.t
+++ b/t/stat-helpers.t
@@ -100,4 +100,21 @@ is stat_as_file( atime => 8, mtime => 9, ctime => 10 ), $expect, 'atime + mtime
 
 is stat_as_file( perms => 0755 ), [ 0, 0, S_IFREG | 0755, (0) x 10 ], 'stat_as_file with perms 0755';
 
+# keys with st_ prefix and mixed case should work
+$expect = [@regular_file];
+$expect->[7] = 42;
+is stat_as_file( st_size => 42 ), $expect, 'st_size prefix accepted';
+
+$expect = [@regular_file];
+$expect->[7] = 99;
+is stat_as_file( SIZE => 99 ), $expect, 'uppercase SIZE accepted';
+
+$expect = [@regular_file];
+$expect->[7] = 55;
+is stat_as_file( St_Size => 55 ), $expect, 'mixed case St_Size accepted';
+
+$expect = [@regular_file];
+$expect->[9] = 12345;
+is stat_as_file( ST_MTIME => 12345 ), $expect, 'ST_MTIME accepted';
+
 done_testing;