fun: tomato plant is a tile entity

server/fixtures/tomato-plant.entity.js

@@ -69,6 +69,7 @@ export function tomatoPlantJSON() {
       },
       positioned: {},
       roomed: {},
+      'tile-entity': {},
       visible: {},
     },
   };

server/fixtures/tomato-seeds.entity.js

@@ -2,6 +2,13 @@ import {buildInvoke, buildTraversal, buildCondition} from '@avocado/behavior';
 
 // Tomato seeds.
 export function tomatoSeedsJSON() {
+  const hasExistingTomato = buildInvoke(
+    ['wielder', 'layer', 'hasTileEntityWithUriAt'],
+    [
+      buildTraversal(['target']),
+      '/tomato-plant.entity.json',
+    ],
+  );
   return {
     traits: {
       existent: {},
@@ -30,14 +37,20 @@ export function tomatoSeedsJSON() {
       tool: {
         params: {
           // Has to be wet dirt.
-          condition: buildCondition('is', [
-            7,
-            buildInvoke(
-              ['wielder', 'layer', 'tileAt'],
-              [
-                buildTraversal(['target']),
-              ],
-            ),
+          condition: buildCondition('and', [
+            buildCondition('is', [
+              7,
+              buildInvoke(
+                ['wielder', 'layer', 'tileAt'],
+                [
+                  buildTraversal(['target']),
+                ],
+              ),
+            ]),
+            buildCondition('is', [
+              false,
+              hasExistingTomato,
+            ]),
           ]),
           actions: {
             type: 'actions',