Clarify subagent coordination cards

app/androidApp/src/test/kotlin/com/example/aiapp/ToolInputTest.kt

@@ -3,6 +3,7 @@ package com.example.aiapp
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertNull
+import kotlin.test.assertTrue
 
 class ToolInputTest {
     @Test
@@ -26,4 +27,17 @@ class ToolInputTest {
         assertNull(renderedBashScript("/usr/bin/bash -lc echo hello"))
         assertNull(renderedBashScript("/usr/bin/fish -lc 'echo hello'"))
     }
+
+    @Test
+    fun `missing optional input is not displayed as null`() {
+        assertTrue(parseToolInput("TaskOutput", "null").rest.isEmpty())
+    }
+
+    @Test
+    fun `collaboration calls say what they do and omit empty completion`() {
+        assertEquals("Spawn agent", toolDisplayName("Task"))
+        assertEquals("Wait for agents", toolDisplayName("TaskOutput"))
+        assertEquals("", toolDisplayOutput("TaskOutput", "completed"))
+        assertEquals("failed", toolDisplayOutput("TaskOutput", "failed"))
+    }
 }