Clarify subagent coordination cards

app/androidApp/src/main/kotlin/com/example/aiapp/ToolInput.kt

@@ -68,12 +68,14 @@ private val SUBJECTS: Map<String, Pair<String, Language?>> =
 private val DESCRIPTIONS = listOf("description", "prompt")
 
 fun parseToolInput(tool: String, input: String): ToolInput {
+    if (input.trim() == "null") return ToolInput(null, null, null, null, emptyList())
     val json =
         try {
             JSONObject(input)
         } catch (_: org.json.JSONException) {
             // Not an object: older transcripts and some tools send a bare string. It is still the
-            // input, so it is still shown.
+            // input, so it is still shown. JSON null is the one exception: it means the call had
+            // no input, and drawing the word makes an absent value look like an instruction.
             return ToolInput(
                 null,
                 null,
@@ -85,17 +87,18 @@ fun parseToolInput(tool: String, input: String): ToolInput {
     val (subjectKey, language) = SUBJECTS[tool] ?: (null to null)
     val subject =
         subjectKey
-            ?.let { json.optString(it) }
+            ?.let { json.text(it) }
             ?.takeIf { it.isNotBlank() }
             ?.let { if (tool == "Bash") renderedBashScript(it) ?: it else it }
     val description = DESCRIPTIONS.firstNotNullOfOrNull {
-        json.optString(it).takeIf { v -> v.isNotBlank() }
+        json.text(it)?.takeIf { value -> value.isNotBlank() }
     }
-    val timeout = json.optString("timeout").takeIf { it.isNotBlank() }?.let { formatMillisText(it) }
+    val timeout = json.text("timeout")?.takeIf { it.isNotBlank() }?.let { formatMillisText(it) }
     val rest =
         json
             .keys()
             .asSequence()
+            .filterNot(json::isNull)
             .filter { it != subjectKey || subject == null }
             .filter { it !in DESCRIPTIONS || description == null }
             .filter { it != "timeout" || timeout == null }
@@ -105,6 +108,9 @@ fun parseToolInput(tool: String, input: String): ToolInput {
     return ToolInput(subject, language, description, timeout, rest)
 }
 
+private fun JSONObject.text(key: String): String? =
+    if (isNull(key)) null else optString(key).takeIf { it.isNotEmpty() }
+
 /**
  * Removes Codex's rendered Bash argv from old transcript rows.
  *

app/androidApp/src/main/kotlin/com/example/aiapp/ToolRows.kt

@@ -295,12 +295,14 @@ fun ToolCard(
     shape: Shape = CardDefaults.shape,
 ) {
     val parsed = remember(tool.tool, tool.input) { parseToolInput(tool.tool, tool.input) }
+    val name = toolDisplayName(tool.tool)
+    val output = toolDisplayOutput(tool.tool, tool.output)
     val deciding = tool.asks.any { it.answers.isEmpty() }
     val open = expanded || deciding
     Card(Modifier.fillMaxWidth().clickable(onClick = onToggle), shape = shape) {
         Column(Modifier.padding(GROUP_INSET_LARGE)) {
             Row(verticalAlignment = Alignment.CenterVertically) {
-                Text(tool.tool, style = MaterialTheme.typography.titleSmall)
+                Text(name, style = MaterialTheme.typography.titleSmall)
                 if (open) {
                     Spacer(Modifier.weight(1f))
                     parsed.timeout?.let {
@@ -355,7 +357,7 @@ fun ToolCard(
                 if (tool.tool != ASK_USER_QUESTION) {
                     ToolInputView(tool.tool, tool.input, Modifier.padding(top = 4.dp))
                 }
-                if (tool.output.isNotEmpty()) {
+                if (output.isNotEmpty()) {
                     Spacer(Modifier.height(8.dp))
                     Text("Output", style = MaterialTheme.typography.labelSmall)
                     // What the tool printed, on the surface everything verbatim gets and in the
@@ -367,7 +369,7 @@ fun ToolCard(
                     // often the whole of what a diff or a test run is saying. Remembered against
                     // the text, so a card that is open through a scroll parses once.
                     val palette = remember { ansiPalette() }
-                    val styled = remember(tool.output, palette) { ansiStyled(tool.output, palette) }
+                    val styled = remember(output, palette) { ansiStyled(output, palette) }
                     RawBlock(Modifier.padding(top = 2.dp)) {
                         Text(
                             styled,
@@ -391,6 +393,22 @@ fun ToolCard(
     }
 }
 
+private val collaborationToolNames =
+    mapOf(
+        "Task" to "Spawn agent",
+        "TaskOutput" to "Wait for agents",
+        "SendMessage" to "Message agent",
+        "CloseAgent" to "Close agent",
+        "InterruptAgent" to "Interrupt agent",
+        "ListAgents" to "List agents",
+        "ResumeAgent" to "Resume agent",
+    )
+
+internal fun toolDisplayName(tool: String): String = collaborationToolNames[tool] ?: tool
+
+internal fun toolDisplayOutput(tool: String, output: String): String =
+    if (tool in collaborationToolNames && output == "completed") "" else output
+
 /**
  * The permission ask on the call it is about.
  *