ios: add tool call stacking

ios/Packages/Sybil/Tests/SybilTests/SybilTests.swift

@@ -402,6 +402,70 @@ private func makeSearchDetail(id: String, date: Date, answer: String) -> SearchD
     )
 }
 
+private func makeToolCallMessage(id: String, date: Date, summary: String = "Ran a tool") -> Message {
+    Message(
+        id: id,
+        createdAt: date,
+        role: .tool,
+        content: summary,
+        name: "web_search",
+        metadata: .object([
+            "kind": .string("tool_call"),
+            "toolCallId": .string("call-\(id)"),
+            "toolName": .string("web_search"),
+            "status": .string("completed"),
+            "summary": .string(summary),
+            "durationMs": .number(120)
+        ])
+    )
+}
+
+@Test func transcriptRenderItemsGroupAdjacentToolCalls() async throws {
+    let date = Date(timeIntervalSince1970: 1_700_000_000)
+    let user = Message(id: "user-1", createdAt: date, role: .user, content: "Search this", name: nil)
+    let toolA = makeToolCallMessage(id: "tool-a", date: date, summary: "Search A")
+    let toolB = makeToolCallMessage(id: "tool-b", date: date, summary: "Search B")
+    let assistant = Message(id: "assistant-1", createdAt: date, role: .assistant, content: "Answer", name: nil)
+
+    let items = buildTranscriptRenderItems(from: [user, toolA, toolB, assistant])
+
+    #expect(items.count == 3)
+    guard case let .message(firstMessage) = items[0] else {
+        Issue.record("Expected the first item to remain a normal message")
+        return
+    }
+    #expect(firstMessage.id == "user-1")
+
+    guard case let .toolGroup(groupID, groupedMessages) = items[1] else {
+        Issue.record("Expected adjacent tool calls to be grouped")
+        return
+    }
+    #expect(groupID == "tool-a")
+    #expect(groupedMessages.map(\.id) == ["tool-a", "tool-b"])
+
+    guard case let .message(lastMessage) = items[2] else {
+        Issue.record("Expected the assistant response to remain a normal message")
+        return
+    }
+    #expect(lastMessage.id == "assistant-1")
+}
+
+@Test func transcriptRenderItemsKeepSingleToolCallsInline() async throws {
+    let date = Date(timeIntervalSince1970: 1_700_000_000)
+    let user = Message(id: "user-1", createdAt: date, role: .user, content: "Search this", name: nil)
+    let tool = makeToolCallMessage(id: "tool-a", date: date)
+    let assistant = Message(id: "assistant-1", createdAt: date, role: .assistant, content: "Answer", name: nil)
+
+    let items = buildTranscriptRenderItems(from: [user, tool, assistant])
+
+    #expect(items.count == 3)
+    guard case let .message(toolMessage) = items[1] else {
+        Issue.record("Expected a single tool call to use the existing inline chip")
+        return
+    }
+    #expect(toolMessage.id == "tool-a")
+}
+
 @MainActor
 @Test func normalizedAPIBaseURLPreservesExplicitAPIPath() async throws {
     let defaults = UserDefaults(suiteName: #function)!