fix(chat): bind tool milestone dividers to message id and exclude synthetic rows (#1095)

app/src/main/java/com/m57/hermescontrol/ui/chat/ChatListEntries.kt

@@ -25,33 +25,66 @@ import androidx.compose.ui.unit.sp
  */
 const val TOOL_CALL_DIVIDER_INTERVAL = 5
 
+private const val MAX_ITERATIONS_SYSTEM_MARKER =
+    "You've reached the maximum number of tool-calling iterations allowed."
+
 /**
- * Returns the message indices that complete a tool-call milestone — a [MessageRole.TOOL]
+ * A genuine user message that establishes a new turn boundary.
+ * Timeline markers (`displayKind != null`) and synthetic system rows
+ * (such as max-iterations nudges) ride with `role == MessageRole.USER`
+ * in storage but belong to the surrounding agent turn.
+ */
+internal fun ChatMessage.isUserTurnBoundary(): Boolean =
+    role == MessageRole.USER &&
+        displayKind == null &&
+        !content.startsWith(MAX_ITERATIONS_SYSTEM_MARKER)
+
+/**
+ * Returns the message IDs that complete a tool-call milestone — a [MessageRole.TOOL]
  * message whose per-turn tool-call count is a multiple of [TOOL_CALL_DIVIDER_INTERVAL] —
  * mapped to the per-turn count at that point.
  *
- * The counter resets at each [MessageRole.USER] message (a new turn), so
+ * The counter resets at each genuine user turn boundary ([isUserTurnBoundary]), so
  * milestones read `5, 10, 15...` within a turn and restart at `5` on the next.
  */
-fun toolCallMilestones(messages: List<ChatMessage>): Map<Int, Int> {
+fun toolCallMilestones(messages: List<ChatMessage>): Map<String, Int> {
-    val milestones = mutableMapOf<Int, Int>()
+    val milestones = mutableMapOf<String, Int>()
     var toolCount = 0
-    messages.forEachIndexed { index, message ->
+    messages.forEach { message ->
-        when (message.role) {
+        when {
-            MessageRole.USER -> {
+            message.isUserTurnBoundary() -> {
                 toolCount = 0
             }
 
-            MessageRole.TOOL -> {
+            message.role == MessageRole.TOOL -> {
+                toolCount += 1
+                if (toolCount % TOOL_CALL_DIVIDER_INTERVAL == 0) {
+                    milestones[message.id] = toolCount
+                }
+            }
+        }
+    }
+    return milestones
+}
+
+/**
+ * Index-based milestone map for position-based callers and backwards compatibility.
+ */
+fun toolCallMilestoneIndices(messages: List<ChatMessage>): Map<Int, Int> {
+    val milestones = mutableMapOf<Int, Int>()
+    var toolCount = 0
+    messages.forEachIndexed { index, message ->
+        when {
+            message.isUserTurnBoundary() -> {
+                toolCount = 0
+            }
+
+            message.role == MessageRole.TOOL -> {
                 toolCount += 1
                 if (toolCount % TOOL_CALL_DIVIDER_INTERVAL == 0) {
                     milestones[index] = toolCount
                 }
             }
-
-            else -> {
-                Unit
-            }
         }
     }
     return milestones

app/src/main/java/com/m57/hermescontrol/ui/chat/fullbleed/FullBleedChatList.kt

@@ -85,7 +85,7 @@ fun FullBleedChatList(
             )
         }
     } else {
-        val toolMilestones = toolCallMilestones(messages)
+        val toolMilestones = remember(messages) { toolCallMilestones(messages) }
         val turns =
             remember(messages, streamingMessage) {
                 groupIntoTurnsWithStreaming(messages, streamingMessage)
@@ -148,14 +148,12 @@ fun FullBleedChatList(
                     }
                 }
 
-                var entryIndex = 0
                 turns.forEach { turn ->
                     when (turn) {
                         is ChatTurn.User -> {
                             // Eager captures: item lambda reads these at
                             // composition time (lazy), so capture now.
                             val userMessage = turn.message
-                            val milestone = toolMilestones[entryIndex]
                             item(key = "user-${userMessage.id}") {
                                 Column(modifier = Modifier.padding(bottom = 12.dp)) {
                                     renderChatBubble(
@@ -170,12 +168,8 @@ fun FullBleedChatList(
                                         openingAttachmentPath = openingAttachmentPath,
                                         onImageClick = onImageClick,
                                     )
-                                    milestone?.let { count ->
-                                        ToolCallDivider(count = count, maxPerTurn = maxToolCallsPerTurn)
-                                    }
                                 }
                             }
-                            entryIndex++
                         }
 
                         is ChatTurn.Agent -> {
@@ -210,7 +204,6 @@ fun FullBleedChatList(
                                         val hoistedReasoning =
                                             turnReasoning != null &&
                                                 proseMessage.id == turnReasoning.message.id
-                                        val milestone = toolMilestones[entryIndex]
                                         item(key = "prose-${proseMessage.id}") {
                                             Column(modifier = Modifier.padding(bottom = 12.dp)) {
                                                 if (proseMessage.isStreaming && typingEffectEnabled) {
@@ -248,18 +241,14 @@ fun FullBleedChatList(
                                                         onImageClick = onImageClick,
                                                     )
                                                 }
-                                                milestone?.let { count ->
-                                                    ToolCallDivider(count = count, maxPerTurn = maxToolCallsPerTurn)
-                                                }
                                             }
                                         }
                                         firstProseSeen = true
-                                        entryIndex++
                                     }
 
                                     is AgentEntry.ToolRow -> {
                                         val toolMessage = entry.message
-                                        val milestone = toolMilestones[entryIndex]
+                                        val milestone = toolMilestones[toolMessage.id]
                                         item(key = "tool-${toolMessage.id}") {
                                             Column(modifier = Modifier.padding(bottom = 6.dp)) {
                                                 FullBleedToolRow(toolMessage)
@@ -268,7 +257,6 @@ fun FullBleedChatList(
                                                 }
                                             }
                                         }
-                                        entryIndex++
                                     }
 
                                     is AgentEntry.SystemEvent -> {
@@ -288,7 +276,6 @@ fun FullBleedChatList(
                                                 }
                                             }
                                         }
-                                        entryIndex++
                                     }
                                 }
                             }

app/src/test/java/com/m57/hermescontrol/ui/chat/ChatListEntriesTest.kt

@@ -31,13 +31,18 @@ class ChatListEntriesTest {
     @Test
     fun fifthToolCallIsAMilestone() {
         val messages = List(5) { toolMessage() }
-        assertEquals(mapOf(4 to 5), toolCallMilestones(messages))
+        assertEquals(mapOf(messages[4].id to 5), toolCallMilestones(messages))
+        assertEquals(mapOf(4 to 5), toolCallMilestoneIndices(messages))
     }
 
     @Test
     fun milestoneAtEveryFifthToolCallWithinTurn() {
         val messages = List(12) { toolMessage() }
-        assertEquals(mapOf(4 to 5, 9 to 10), toolCallMilestones(messages))
+        assertEquals(
+            mapOf(messages[4].id to 5, messages[9].id to 10),
+            toolCallMilestones(messages),
+        )
+        assertEquals(mapOf(4 to 5, 9 to 10), toolCallMilestoneIndices(messages))
     }
 
     @Test
@@ -57,7 +62,56 @@ class ChatListEntriesTest {
                 toolMessage(), // 10
                 toolMessage(), // 11 ← 5th tool call of turn 2 (not 10)
             )
-        assertEquals(mapOf(5 to 5, 11 to 5), toolCallMilestones(messages))
+        assertEquals(
+            mapOf(messages[5].id to 5, messages[11].id to 5),
+            toolCallMilestones(messages),
+        )
+        assertEquals(mapOf(5 to 5, 11 to 5), toolCallMilestoneIndices(messages))
+    }
+
+    @Test
+    fun timelineMarkerDoesNotResetToolCounter() {
+        val marker =
+            ChatMessage(
+                role = MessageRole.USER,
+                content = "[System: The active model has changed to gpt-5]",
+                displayKind = "model_switch",
+            )
+        val messages =
+            listOf(
+                userMessage(),
+                toolMessage(),
+                toolMessage(),
+                marker,
+                toolMessage(),
+                toolMessage(),
+                toolMessage(), // 5th tool call despite intervening marker
+            )
+        assertEquals(mapOf(messages[6].id to 5), toolCallMilestones(messages))
+        assertEquals(mapOf(6 to 5), toolCallMilestoneIndices(messages))
+    }
+
+    @Test
+    fun syntheticMaxIterationsNudgeDoesNotResetToolCounter() {
+        val nudge =
+            ChatMessage(
+                role = MessageRole.USER,
+                content =
+                    "You've reached the maximum number of tool-calling iterations allowed. " +
+                        "Please provide a summary.",
+            )
+        val messages =
+            listOf(
+                userMessage(),
+                toolMessage(),
+                toolMessage(),
+                toolMessage(),
+                nudge,
+                toolMessage(),
+                toolMessage(), // 5th tool call despite intervening nudge
+            )
+        assertEquals(mapOf(messages[6].id to 5), toolCallMilestones(messages))
+        assertEquals(mapOf(6 to 5), toolCallMilestoneIndices(messages))
     }
 
     @Test
@@ -73,13 +127,15 @@ class ChatListEntriesTest {
                 textMessage(), // 6
                 toolMessage(), // 7 ← 5th tool call
             )
-        assertEquals(mapOf(7 to 5), toolCallMilestones(messages))
+        assertEquals(mapOf(messages[7].id to 5), toolCallMilestones(messages))
+        assertEquals(mapOf(7 to 5), toolCallMilestoneIndices(messages))
     }
 
     @Test
     fun toolMessagesWithoutToolNameStillCount() {
         val messages = List(5) { ChatMessage(role = MessageRole.TOOL, content = "", toolName = null) }
-        assertEquals(mapOf(4 to 5), toolCallMilestones(messages))
+        assertEquals(mapOf(messages[4].id to 5), toolCallMilestones(messages))
+        assertEquals(mapOf(4 to 5), toolCallMilestoneIndices(messages))
     }
 
     @Test