Keep tool group keys unique across transcript

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

@@ -113,24 +113,27 @@ private fun groupRuns(
 ): List<TranscriptRow> {
     val rows = mutableListOf<TranscriptRow>()
     var run = mutableListOf<TranscriptItem.ToolRun>()
-    // The run being walked, and how many rows it has produced so far -- which is what decides the
-    // keys below.
+    // A run can occupy more than one non-adjacent piece, so claimed keys span the whole transcript
+    // rather than resetting at each piece.
     var runId: String? = null
-    var emitted = 0
+    val claimedKeys = mutableSetOf<String>()
 
     fun flush() {
         val first = run.firstOrNull() ?: return
-        // The first row a run produces keeps the run's name, which is the name that survives a page
-        // of history landing in front of it ([adoptRun]); losing it is the transcript stepping
-        // under whoever is reading. The pieces a call standing on its own cuts off the back of the
-        // run have no such name, so each takes its own first call's id, which is unique because a
-        // call id is. The run's name goes in front of it because the two can otherwise be the same
-        // string: the call a run was named after can itself be the one standing on its own.
-        val key = if (emitted == 0) first.runId else "${first.runId}/${first.id}"
+        // The first piece keeps the run's name, which survives a page landing in front of it
+        // ([adoptRun]). Later pieces qualify that name with their first call; the suffix is the
+        // final guard because a duplicate LazyColumn key takes down the whole screen.
+        var key = first.runId
+        if (!claimedKeys.add(key)) {
+            key = "${first.runId}/${first.id}"
+            var suffix = 2
+            while (!claimedKeys.add(key)) {
+                key = "${first.runId}/${first.id}/${suffix++}"
+            }
+        }
         rows +=
             if (run.size == 1) TranscriptRow.Single(first, key)
             else TranscriptRow.Tools(run.toList(), key)
-        emitted++
         run = mutableListOf()
     }
 
@@ -143,7 +146,6 @@ private fun groupRuns(
         if (call == null || call.runId != runId) {
             flush()
             runId = call?.runId
-            emitted = 0
         }
         when {
             call == null -> rows += TranscriptRow.Single(item)

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

@@ -111,6 +111,27 @@ class ToolRowsTest {
         assertEquals("b", rows.first().key)
     }
 
+    @Test
+    fun a_run_that_reappears_after_another_row_keeps_distinct_keys() {
+        val rows =
+            groupToolRuns(
+                listOf(
+                    call("older", runId = "exec-1"),
+                    call("older-2", runId = "exec-1"),
+                    reply(),
+                    call("exec-1", runId = "exec-1"),
+                    call("newer", runId = "exec-1"),
+                    reply(),
+                )
+            )
+
+        assertTrue(rows[0] is TranscriptRow.Tools, "$rows")
+        assertTrue(rows[2] is TranscriptRow.Tools, "$rows")
+        assertKeysDistinct(rows)
+        assertEquals("exec-1", rows[0].key)
+        assertEquals("exec-1/exec-1", rows[2].key)
+    }
+
     /**
      * Finishing is not what folds a call back in -- being overtaken is. A session that has run its
      * last command and is writing its reply leaves that command standing until the reply starts.