diff --git a/lib/Devel/IPerl/Plugin/Perlbrew.pm b/lib/Devel/IPerl/Plugin/Perlbrew.pm
index fa52e97..91e11cc 100644
--- a/lib/Devel/IPerl/Plugin/Perlbrew.pm
+++ b/lib/Devel/IPerl/Plugin/Perlbrew.pm
@@ -154,6 +154,13 @@ sub success { scalar(keys %{$_[0]->{env}}) ? 1 : 0; }
 
 sub unload { return $_[0]{unload} if @_ == 1; $_[0]{unload} = $_[1]; $_[0]; }
 
+sub _check_env_perl {
+  my ($env_perl, $path_perl) = (shift, _from_binary_path());
+  $ENV{PERLBREW_PERL} = $env_perl = $path_perl unless $env_perl;
+  return $env_perl unless $path_perl;
+  return ($env_perl eq $path_perl ? $env_perl : $ENV{PERLBREW_PERL} = $path_perl);
+}
+
 sub _filtered_env_keys {
   return (sort grep { m/^PERL/i && $_ ne "PERL5LIB" } keys %{+pop});
 }
@@ -167,19 +174,41 @@ sub _from_binary_path {
 
 sub _make_name {
   my ($class, $name, $current) =
-    (shift, shift, $ENV{PERLBREW_PERL} || _from_binary_path());
-  my ($perl, $lib) =
-    split /\@/, ($name =~ m/\@/ || $name eq $current ? $name : "\@$name");
-  $perl = $class->_resolve_compat($perl) || $current;
+    (shift, shift, _check_env_perl($ENV{PERLBREW_PERL}));
+  my $pb = PERLBREW_CLASS->new();
+  my ($perl, $lib) = $pb->resolve_installation_name($name);
+  if ((! defined($perl))){
+    if ($name =~ m/\@[^\@]+$/) {
+      ($perl, $lib) = $pb->resolve_installation_name(join '@', $current, (split /\@/, $name)[1]);
+    } elsif($name !~ /\@/ && $name !~ /^[\d\.]+$/){
+      ($perl, $lib) = $pb->resolve_installation_name(join '@', $current, $name);
+    }
+  }
+  $perl = $class->_resolve_compat($pb, $perl, $current, $lib) || $current;
   return $perl unless $lib;
   return join '@', $perl, $lib;
 }
 
 sub _resolve_compat {
-  my ($class, $perl) = (shift, shift);
-  my $pb = PERLBREW_CLASS->new;
-  my ($current) = grep { $_->{is_current} } $pb->installed_perls;
-  return $pb->resolve_installation_name($current->{version}) || '';
+  my ($class, $pb, $perl, $current, $lib) = @_;
+  return '' unless $lib;
+  my @installed = $pb->installed_perls;
+  # get the current perl and version
+  my ($current_perl)  = grep { $_->{name} eq $current } @installed;
+  my $current_version = $current_perl->{comparable_version};
+
+  my ($avail) = (
+    # filter the exact
+    grep { $_->{perl_name} eq $perl && $_->{lib_name} eq $lib }
+    # get the libraries only
+    map  { @{$_->{libs}} }
+    # filter the compatible libraries
+    grep { $_->{comparable_version} == $current_version } @installed
+    );
+  #use Data::Dumper;
+  #say STDERR Dumper $current_perl, $current_version, \@installed if DEBUG;
+  return '' unless $avail;
+  return $avail->{perl_name};
 }
 
 ## from Mojo::Util
diff --git a/t/iperl-perlbrew.t b/t/iperl-perlbrew.t
index 668e03a..6326763 100644
--- a/t/iperl-perlbrew.t
+++ b/t/iperl-perlbrew.t
@@ -9,36 +9,15 @@ use Devel::IPerl;
 use IPerl;
 use lib 't/lib';
 
-sub test_perlbrew_perl {
-  (my $perl = $^V->normal) =~ s{^v}{perl-};
-  return $perl;
-}
-
-my $iperl = new_ok('IPerl');
-
-ok $iperl->load_plugin('Perlbrew');
 my $domain = $ENV{PERLBREW_HOME} || '';
-
+my $iperl  = new_ok('IPerl');
+ok $iperl->load_plugin('Perlbrew');
 can_ok $iperl, qw{perlbrew perlbrew_domain perlbrew_lib_create perlbrew_list
                   perlbrew_list_modules};
 
-is $iperl->perlbrew(), -1, 'no library for app::perlbrew';
-
-my $save = $ENV{PERLBREW_ROOT};
-
-is $iperl->perlbrew('random1'), 1, 'here';
-is $iperl->perlbrew('random2'), 1, 'here';
-is $iperl->perlbrew('random2'), 0, 'here';
-
-is $ENV{PERLBREW_ROOT}, $save, 'no change';
-is $ENV{PERLBREW_HOME}, '/tmp', 'set';
-
-is $iperl->perlbrew_domain, $domain, 'domain from register';
-is $iperl->perlbrew_domain('/tmp'), '/tmp', 'domain set';
-
-my @added = grep { m{^\Q$Test::App::perlbrew::PERL5LIB\E$} } @INC;
-is @added, 1, "contains path '$Test::App::perlbrew::PERL5LIB'";
-
+#
+# Test the internal plugin interface first
+#
 my $plugin = new_ok('Devel::IPerl::Plugin::Perlbrew');
 is $plugin->name, undef, 'empty default';
 is $plugin->name('perl-5.26.0@random'), $plugin, 'chaining';
@@ -91,16 +70,59 @@ $plugin->new(name => 'foo')->new({name => 'bar'})->brew;
 
 # _make_name tests check various constraints
 {
-  local $ENV{PERLBREW_PERL} = $ENV{PERLBREW_PERL} || test_perlbrew_perl();
-  (my $current_perl = $^X) =~ s{.*/perls/([^/]+)/bin/perl}{$1};
-  is $plugin->_make_name('foo'), join('@', $ENV{PERLBREW_PERL}, 'foo'),
-    'make name';
-  is $plugin->_make_name($ENV{PERLBREW_PERL}), $ENV{PERLBREW_PERL},
-    'current perl';
+  local $ENV{PERLBREW_PERL} = 'perl-alias';
+  (local $^X = $^X) =~ s{perls/([^/]+)/bin}{perls/perl-alias/bin};
+
+  is $plugin->_make_name('alias@example'), 'perl-alias@example',
+    'perl match current with existing lib';
+  is $plugin->_make_name('alias@lib'),     'perl-alias@lib',
+    'perl match current with new lib';
+  is $plugin->_make_name('5.26.0@random'), 'perl-5.26.0@random',
+    'perl with same version, and existing lib';
+  ## the current perl is preferred when neither have the library.
+  is $plugin->_make_name('5.26.0@example'), 'perl-alias@example',
+    'perl with same version, and new lib - these cannot be created';
+  ## cannot switch to this library free compatible perl
+  is $plugin->_make_name('5.26.0'),        'perl-alias',
+    'installed perl with no lib - cannot be accessed';
+
+  is $plugin->_make_name('5.24.0'),        'perl-alias',
+    'non installed perl with no lib';
+  is $plugin->_make_name('alias'),         'perl-alias',
+    'shortened name with no lib';
+  is $plugin->_make_name('alias@random'),  'perl-alias@random',  '';
+  is $plugin->_make_name('5.26.0@random'), 'perl-5.26.0@random', '';
+
+  # some helpful versions
+  is $plugin->_make_name('foo-bar-baz'),  'perl-alias@foo-bar-baz',
+    'no perl, just a libray (new), without @';
+  is $plugin->_make_name('foo'),          'perl-alias@foo',
+    'no perl, just a libray, without @';
+  is $plugin->_make_name('@foo'),          'perl-alias@foo',
+    'no perl, just a libray, explicitly with @';
+  is $plugin->_make_name('bad@'),          'perl-alias',
+    'trailing @ is in no way supported';
+  is $plugin->_make_name('rad@rad@rad'),   'perl-alias@rad',
+    'multiple @ will take the element at position 1';
+}
+
+{
+  local $ENV{PERLBREW_PERL} = 'perl-5.8.9';
+  (local $^X = $^X) =~ s{perls/([^/]+)/bin}{perls/perl-5.8.9/bin};
+  is $plugin->_make_name('5.8.9@random'),     'perl-5.8.9@random',
+    'perl match current with new lib';
+  is $plugin->_make_name('5.8.8@archive'),    'perl-5.8.9@archive',
+    'perl match current with new lib';
+  is $plugin->_make_name('5.26.0@random'),    'perl-5.8.9@random',
+    'perl with different version, and existing lib';
+  is $plugin->_make_name('5.26.0'),        'perl-5.8.9',
+    'installed perl with no lib - cannot be accessed';
+
 }
 
 {
   local $ENV{PERLBREW_PERL} = 'perl-5.24.3';
+  (local $^X = $^X) =~ s{perls/([^/]+)/bin}{perls/perl-5.24.3/bin};
   is $plugin->_make_name('bar'), 'perl-5.24.3@bar', 'make name';
   is $plugin->_make_name('perl-5.26.1@bar'), 'perl-5.24.3@bar', 'make name';
   delete $ENV{PERLBREW_PERL};
@@ -112,12 +134,32 @@ $plugin->new(name => 'foo')->new({name => 'bar'})->brew;
     'non-numeric "current" perl';
   ## default to perl version
   $^X =~ s{perls/([^/]+)/bin}{p/perl-alias/bin};
-  my $version = test_perlbrew_perl();
+  (my $version = $^V->normal) =~ s{^v}{perl-};
   is $plugin->_make_name('bar'), join('@', $version, 'bar'), 'make name';
   is $plugin->_make_name('perl-5.26.1@bar'), join('@', $version, 'bar'),
     'make name';
 }
 
+#
+# Now to working on the functionality of plugin functions
+#
+is $iperl->perlbrew(), -1, 'no library for app::perlbrew';
+
+my $save = $ENV{PERLBREW_ROOT};
+
+is $iperl->perlbrew('random1'), 1, 'here';
+is $iperl->perlbrew('random2'), 1, 'here';
+is $iperl->perlbrew('random2'), 0, 'here';
+
+is $ENV{PERLBREW_ROOT}, $save, 'no change';
+is $ENV{PERLBREW_HOME}, '/tmp', 'set';
+
+is $iperl->perlbrew_domain, $domain, 'domain from register';
+is $iperl->perlbrew_domain('/tmp'), '/tmp', 'domain set';
+
+my @added = grep { m{^\Q$Test::App::perlbrew::PERL5LIB\E$} } @INC;
+is @added, 1, "contains path '$Test::App::perlbrew::PERL5LIB'";
+
 is $iperl->perlbrew_lib_create(), -1, 'no lib in lib_create';
 is $iperl->perlbrew_lib_create('special'), 1, 'lib_create';
 is $iperl->perlbrew_lib_create('test-library'), 0,
@@ -143,5 +185,6 @@ is $INC{'ACME/NotThere.pm'}, undef, 'not in %INC';
 eval "ACME::NotThere->heres_johnny;";
 like $@, qr/heres_johnny/, 'nope';
 
-
+# use Data::Dumper;
+# diag Dumper [ Test::App::perlbrew->installed_perls ] ;
 done_testing;
diff --git a/t/lib/Test/App/perlbrew.pm b/t/lib/Test/App/perlbrew.pm
index ebbf8f7..6069439 100644
--- a/t/lib/Test/App/perlbrew.pm
+++ b/t/lib/Test/App/perlbrew.pm
@@ -14,13 +14,38 @@ sub new { bless {}, $_[0]; }
 
 sub home {
 }
-
+sub comparable_perl_version {
+  shift;
+  require App::perlbrew;
+  (
+    App::perlbrew->comparable_perl_version(@_)
+  );
+}
 sub installed_perls {
-  return {
-    name => $ENV{PERLBREW_PERL},
-    version => ((my $a = $ENV{PERLBREW_PERL} || '') =~ s/^perl\-//),
-    is_current => 1,
-  };
+  my $self = shift;
+  my @result;
+  (my $version = $^V->normal) =~ s{^v}{perl-};
+  my %perlset = (
+    $version      => [$self->comparable_perl_version($version)],
+    'perl-5.26.0' => [5260000, qw{foo bar random random1 random2}],
+    'perl-5.24.3' => [5240300, qw{bar}],
+    'perl-alias'  => [5260000, qw{example}],
+    'perl-5.8.9'  => [5080900, qw{archived}],
+  );
+  for my $perl(keys %perlset){
+    my $inst = {
+      name => $perl, comparable_version => shift(@{$perlset{$perl}}), libs => []
+    };
+    for my $lib(@{$perlset{$perl}}) {
+      push @{$inst->{libs}}, {
+        name => join('@', $perl, $lib), lib_name => $lib, perl_name => $perl
+      };
+    }
+    push @result, $inst;
+  }
+# use Data::Dumper;
+#  warn Dumper \@result;
+  return @result;
 }
 
 sub perlbrew_env {
@@ -35,7 +60,17 @@ sub perlbrew_env {
 }
 
 sub resolve_installation_name {
-
+  my ($self, $name) = @_;
+  my ($perl, $lib)  = split '@', $name, 2;
+  my @installed     = $self->installed_perls;
+  if (0 == grep { $_->{name} eq $perl} @installed) {
+    if (grep { $_->{name} eq "perl-$perl" } @installed) {
+      $perl = "perl-$perl";
+    } else {
+      return undef
+    }
+  }
+  return ($perl, $lib);
 }
 
 sub run_command {