diff --git a/firestore/v1/update-exists-false-precond.json b/firestore/v1/update-exists-false-precond.json
new file mode 100644
index 0000000..031fd1a
--- /dev/null
+++ b/firestore/v1/update-exists-false-precond.json
@@ -0,0 +1,16 @@
+{
+  "tests": [
+    {
+      "description": "update: Exists=false precondition is invalid",
+      "comment": "The Update method does not support an explicit exists=false precondition.",
+      "update": {
+        "docRefPath": "projects/projectID/databases/(default)/documents/C/d",
+        "precondition": {
+          "exists": false
+        },
+        "jsonData": "{\"a\": 1}",
+        "isError": true
+      }
+    }
+  ]
+}
diff --git a/firestore/v1/update-exists-precond.json b/firestore/v1/update-exists-true-precond.json
similarity index 84%
rename from firestore/v1/update-exists-precond.json
rename to firestore/v1/update-exists-true-precond.json
index 66e5d11..f1aa800 100644
--- a/firestore/v1/update-exists-precond.json
+++ b/firestore/v1/update-exists-true-precond.json
@@ -1,8 +1,8 @@
 {
   "tests": [
     {
-      "description": "update: Exists precondition is valid",
-      "comment": "The Update method supports an explicit exists precondition.",
+      "description": "update: Exists=true precondition is valid",
+      "comment": "The Update method supports an explicit exists=true precondition.",
       "update": {
         "docRefPath": "projects/projectID/databases/(default)/documents/C/d",
         "precondition": {
diff --git a/firestore/v1/update-paths-exists-false-precond.json b/firestore/v1/update-paths-exists-false-precond.json
new file mode 100644
index 0000000..f122b53
--- /dev/null
+++ b/firestore/v1/update-paths-exists-false-precond.json
@@ -0,0 +1,25 @@
+{
+  "tests": [
+    {
+      "description": "update-paths: Exists=false precondition is invalid",
+      "comment": "The Update method does not support an explicit exists=false precondition.",
+      "updatePaths": {
+        "docRefPath": "projects/projectID/databases/(default)/documents/C/d",
+        "precondition": {
+          "exists": false
+        },
+        "fieldPaths": [
+          {
+            "field": [
+              "a"
+            ]
+          }
+        ],
+        "jsonValues": [
+          "1"
+        ],
+        "isError": true
+      }
+    }
+  ]
+}
diff --git a/firestore/v1/update-paths-exists-precond.json b/firestore/v1/update-paths-exists-true-precond.json
similarity index 86%
rename from firestore/v1/update-paths-exists-precond.json
rename to firestore/v1/update-paths-exists-true-precond.json
index 6325c75..39d61c9 100644
--- a/firestore/v1/update-paths-exists-precond.json
+++ b/firestore/v1/update-paths-exists-true-precond.json
@@ -1,8 +1,8 @@
 {
   "tests": [
     {
-      "description": "update-paths: Exists precondition is valid",
-      "comment": "The Update method supports an explicit exists precondition.",
+      "description": "update-paths: Exists=true precondition is valid",
+      "comment": "The Update method supports an explicit exists=true precondition.",
       "updatePaths": {
         "docRefPath": "projects/projectID/databases/(default)/documents/C/d",
         "precondition": {