diff --git a/authorize_test.go b/authorize_test.go
index 74f7734..fddcaa5 100644
--- a/authorize_test.go
+++ b/authorize_test.go
@@ -35,8 +35,26 @@ func TestIsAuthorized(t *testing.T) {
 			DiagErr:   0,
 		},
 		{
-			Name:      "nil-entity-map",
+			Name:   "permit-when-tags",
+			Policy: `permit(principal,action,resource) when { principal.hasTag("foo") };`,
+			Entities: types.EntityMap{
+				cuzco: types.Entity{
+					Tags: types.NewRecord(cedar.RecordMap{
+						"foo": types.String("bar"),
+					}),
+				},
+			},
+			Principal: cuzco,
+			Action:    dropTable,
+			Resource:  cedar.NewEntityUID("table", "whatever"),
+			Context:   cedar.Record{},
+			Want:      true,
+			DiagErr:   0,
+		},
+		{
+			Name:      "nil-entity-getter",
 			Policy:    `permit(principal,action,resource);`,
+			Entities:  nil,
 			Principal: cuzco,
 			Action:    dropTable,
 			Resource:  cedar.NewEntityUID("table", "whatever"),
@@ -795,7 +813,7 @@ func TestIsAuthorized(t *testing.T) {
 	for _, tt := range tests {
 		tt := tt
 		t.Run(tt.Name, func(t *testing.T) {
-			// t.Parallel()
+			t.Parallel()
 			ps, err := cedar.NewPolicySetFromBytes("policy.cedar", []byte(tt.Policy))
 			testutil.Equals(t, err != nil, tt.ParseErr)
 			ok, diag := ps.IsAuthorized(tt.Entities, cedar.Request{
diff --git a/corpus_test.go b/corpus_test.go
index 1269434..613461c 100644
--- a/corpus_test.go
+++ b/corpus_test.go
@@ -251,21 +251,6 @@ func TestCorpusRelated(t *testing.T) {
 		reasons  []cedar.PolicyID
 		errors   []cedar.PolicyID
 	}{
-		{
-			"a9fe7e4b20024dc7818a168c67ce312d6e076b93",
-			`forbid(
-			principal,
-			action in [Action::"action",Action::"action"],
-			resource
-			) when {
-			true && (resource.hasTag("A"))
-			};`,
-			types.EntityMap{cedar.NewEntityUID("a", ""): cedar.Entity{Attributes: cedar.NewRecord(cedar.RecordMap{"A": types.False})}},
-			cedar.Request{Principal: cedar.NewEntityUID("a", ""), Action: cedar.NewEntityUID("Action", "action"), Resource: cedar.NewEntityUID("a", "'")},
-			cedar.Deny,
-			nil,
-			nil,
-		},
 		{
 			"0cb1ad7042508e708f1999284b634ed0f334bc00",
 			`forbid(
diff --git a/internal/eval/evalers.go b/internal/eval/evalers.go
index 8b43a5e..6fc97ea 100644
--- a/internal/eval/evalers.go
+++ b/internal/eval/evalers.go
@@ -820,8 +820,8 @@ func (n *getTagEval) Eval(env Env) (types.Value, error) {
 		return zeroValue(), err
 	}
 
-	var unspecified types.EntityUID
-	if eid == unspecified {
+	var zero types.EntityUID
+	if eid == zero {
 		return zeroValue(), fmt.Errorf("cannot access tag `%s` of %w", n.rhs, errUnspecifiedEntity)
 	}
 
diff --git a/internal/eval/evalers_test.go b/internal/eval/evalers_test.go
index 5c06694..0580489 100644
--- a/internal/eval/evalers_test.go
+++ b/internal/eval/evalers_test.go
@@ -1505,7 +1505,7 @@ func TestGetTagNode(t *testing.T) {
 			newLiteralEval(knownTag),
 			zeroValue(),
 			errEntityNotExist},
-		{"UnspecifiedEntity",
+		{"ZeroEntity",
 			newLiteralEval(types.NewEntityUID("", "")),
 			newLiteralEval(knownTag),
 			zeroValue(),
diff --git a/types/entity.go b/types/entity.go
index a4c1f5a..931dab1 100644
--- a/types/entity.go
+++ b/types/entity.go
@@ -11,7 +11,7 @@ type Entity struct {
 	UID        EntityUID    `json:"uid"`
 	Parents    EntityUIDSet `json:"parents"`
 	Attributes Record       `json:"attrs"`
-	Tags       Record       `json:"tags,omitempty"`
+	Tags       Record       `json:"tags"`
 }
 
 // MarshalJSON serializes Entity as a JSON object, using the implicit form of EntityUID encoding to match the Rust
diff --git a/types/entity_tag_test.go b/types/entity_tag_test.go
deleted file mode 100644
index e365458..0000000
--- a/types/entity_tag_test.go
+++ /dev/null
@@ -1,46 +0,0 @@
-package types_test
-
-import (
-	"testing"
-	"time"
-
-	"github.com/cedar-policy/cedar-go"
-	"github.com/cedar-policy/cedar-go/internal/testutil"
-	"github.com/cedar-policy/cedar-go/types"
-)
-
-func TestEntityTagMarshalJSON(t *testing.T) {
-	t.Parallel()
-	e := types.Entity{
-		UID:        types.NewEntityUID("FooType", "1"),
-		Parents:    types.NewEntityUIDSet(),
-		Attributes: types.Record{},
-		Tags: cedar.NewRecord(types.RecordMap{
-			"key":      types.String("value"),
-			"entity":   types.NewEntityUID("FootType", "1"),
-			"datetime": types.NewDatetime(time.Unix(0, 0)),
-		}),
-	}
-
-	testutil.JSONMarshalsTo(t, e,
-		`{
-			"uid": {"type":"FooType","id":"1"},
-			"parents": [],
-			"attrs":{},
-            "tags": {
-        		"datetime": {
-        			"__extn": {
-        				"fn": "datetime",
-        				"arg": "1970-01-01T00:00:00.000Z"
-        			}
-        		},
-        		"entity": {
-        			"__entity": {
-        				"type": "FootType",
-        				"id": "1"
-        			}
-        		},
-        		"key": "value"
-            }
-		}`)
-}
diff --git a/types/entity_test.go b/types/entity_test.go
index 9b6ce4d..5a97349 100644
--- a/types/entity_test.go
+++ b/types/entity_test.go
@@ -2,6 +2,7 @@ package types_test
 
 import (
 	"testing"
+	"time"
 
 	"github.com/cedar-policy/cedar-go/internal/testutil"
 	"github.com/cedar-policy/cedar-go/types"
@@ -57,3 +58,39 @@ func TestEntityMarshalJSON(t *testing.T) {
 			"tags":{}
 		}`)
 }
+
+func TestEntityTagMarshalJSON(t *testing.T) {
+	t.Parallel()
+	e := types.Entity{
+		UID:        types.NewEntityUID("FooType", "1"),
+		Parents:    types.NewEntityUIDSet(),
+		Attributes: types.Record{},
+		Tags: types.NewRecord(types.RecordMap{
+			"key":      types.String("value"),
+			"entity":   types.NewEntityUID("FootType", "1"),
+			"datetime": types.NewDatetime(time.Unix(0, 0)),
+		}),
+	}
+
+	testutil.JSONMarshalsTo(t, e,
+		`{
+			"uid": {"type":"FooType","id":"1"},
+			"parents": [],
+			"attrs":{},
+            "tags": {
+        		"datetime": {
+        			"__extn": {
+        				"fn": "datetime",
+        				"arg": "1970-01-01T00:00:00.000Z"
+        			}
+        		},
+        		"entity": {
+        			"__entity": {
+        				"type": "FootType",
+        				"id": "1"
+        			}
+        		},
+        		"key": "value"
+            }
+		}`)
+}