diff --git a/lib/bds/ai/chat.ex b/lib/bds/ai/chat.ex
index f3aa36a..d7e602a 100644
--- a/lib/bds/ai/chat.ex
+++ b/lib/bds/ai/chat.ex
@@ -479,10 +479,44 @@ defmodule BDS.AI.Chat do
case Catalog.decode_nullable_json(message.tool_calls) do
nil -> base
- tool_calls -> Map.put(base, "tool_calls", tool_calls)
+ tool_calls -> Map.put(base, "tool_calls", tool_calls_for_runtime(tool_calls))
end
end
+ defp tool_calls_for_runtime(tool_calls) when is_list(tool_calls) do
+ Enum.map(tool_calls, &tool_call_for_runtime/1)
+ end
+
+ defp tool_calls_for_runtime(tool_calls), do: tool_calls
+
+ defp tool_call_for_runtime(%{"type" => "function", "function" => %{} = _function} = tool_call) do
+ tool_call
+ end
+
+ defp tool_call_for_runtime(%{"id" => id, "name" => name} = tool_call) do
+ %{
+ "id" => id,
+ "type" => "function",
+ "function" => %{
+ "name" => name,
+ "arguments" => Jason.encode!(tool_call["arguments"] || %{})
+ }
+ }
+ end
+
+ defp tool_call_for_runtime(%{id: id, name: name} = tool_call) do
+ %{
+ "id" => id,
+ "type" => "function",
+ "function" => %{
+ "name" => name,
+ "arguments" => Jason.encode!(Map.get(tool_call, :arguments) || %{})
+ }
+ }
+ end
+
+ defp tool_call_for_runtime(tool_call), do: tool_call
+
defp truncate_chat_messages(messages, model, tools) do
context_window = model_context_window(model)
reserve = min(@default_max_output_tokens, max(div(context_window, 4), 512))
diff --git a/lib/bds/desktop/shell_live/chat_editor/message_build.ex b/lib/bds/desktop/shell_live/chat_editor/message_build.ex
index ea1d893..50bac29 100644
--- a/lib/bds/desktop/shell_live/chat_editor/message_build.ex
+++ b/lib/bds/desktop/shell_live/chat_editor/message_build.ex
@@ -62,6 +62,16 @@ defmodule BDS.Desktop.ShellLive.ChatEditor.MessageBuild do
next_turn_index = turn_index + 1
{entries, start_entry(message, next_turn_index, assigns), next_turn_index}
+ :assistant ->
+ next_entry = start_entry(message, turn_index, assigns)
+
+ if tool_only_assistant_entry?(current_entry) do
+ {entries, merge_tool_only_entry(current_entry, next_entry), turn_index}
+ else
+ entries = finalize_entry(entries, current_entry)
+ {entries, next_entry, turn_index}
+ end
+
_other ->
entries = finalize_entry(entries, current_entry)
{entries, start_entry(message, turn_index, assigns), turn_index}
@@ -99,6 +109,22 @@ defmodule BDS.Desktop.ShellLive.ChatEditor.MessageBuild do
end
end
+ defp tool_only_assistant_entry?(%{role: :assistant, content: content} = entry) do
+ String.trim(content || "") == "" and
+ (entry.tool_markers != [] or entry.inline_surfaces != [] or entry.tool_surfaces != [])
+ end
+
+ defp tool_only_assistant_entry?(_entry), do: false
+
+ defp merge_tool_only_entry(tool_entry, assistant_entry) do
+ %{
+ assistant_entry
+ | tool_markers: tool_entry.tool_markers ++ assistant_entry.tool_markers,
+ inline_surfaces: tool_entry.inline_surfaces ++ assistant_entry.inline_surfaces,
+ tool_surfaces: tool_entry.tool_surfaces ++ assistant_entry.tool_surfaces
+ }
+ end
+
defp pending_user_message(_messages, nil), do: nil
defp pending_user_message(messages, %{message: message}) when is_binary(message) do
diff --git a/test/bds/ai_test.exs b/test/bds/ai_test.exs
index 3726abf..870ced7 100644
--- a/test/bds/ai_test.exs
+++ b/test/bds/ai_test.exs
@@ -602,6 +602,17 @@ defmodule BDS.AITest do
assert get_in(render_chart_schema, ["series", "items", "properties", "segments"]) != nil
assert Enum.any?(second_request.messages, fn message -> message["role"] == "tool" end)
+
+ assert Enum.any?(second_request.messages, fn message ->
+ message["role"] == "assistant" and
+ message["tool_calls"] == [
+ %{
+ "id" => "call-blog-stats",
+ "type" => "function",
+ "function" => %{"name" => "blog_stats", "arguments" => "{}"}
+ }
+ ]
+ end)
end
test "chat does not prompt models to emit textual tool calls when tools are unavailable" do
diff --git a/test/bds/desktop/shell_live_test.exs b/test/bds/desktop/shell_live_test.exs
index 2ff3772..6b10b5a 100644
--- a/test/bds/desktop/shell_live_test.exs
+++ b/test/bds/desktop/shell_live_test.exs
@@ -2216,6 +2216,73 @@ defmodule BDS.Desktop.ShellLiveTest do
assert html =~ "Posts"
end
+ test "chat editor folds tool-only assistant steps into the final assistant answer" do
+ assert {:ok, conversation} = AI.start_chat(%{title: "Tool Chat", model: "gpt-4.1"})
+
+ now = Persistence.now_ms()
+
+ Repo.insert!(
+ BDS.AI.ChatMessage.changeset(%BDS.AI.ChatMessage{}, %{
+ conversation_id: conversation.id,
+ role: :user,
+ content: "Show posts per month",
+ created_at: now
+ })
+ )
+
+ Repo.insert!(
+ BDS.AI.ChatMessage.changeset(%BDS.AI.ChatMessage{}, %{
+ conversation_id: conversation.id,
+ role: :assistant,
+ content: nil,
+ tool_calls:
+ Jason.encode!([
+ %{
+ "id" => "call-count-posts",
+ "name" => "count_posts",
+ "arguments" => %{"groupBy" => ["month"], "year" => 2026}
+ }
+ ]),
+ created_at: now + 1
+ })
+ )
+
+ Repo.insert!(
+ BDS.AI.ChatMessage.changeset(%BDS.AI.ChatMessage{}, %{
+ conversation_id: conversation.id,
+ role: :tool,
+ tool_call_id: "call-count-posts",
+ content: Jason.encode!([%{"month" => 5, "count" => 3}]),
+ created_at: now + 2
+ })
+ )
+
+ Repo.insert!(
+ BDS.AI.ChatMessage.changeset(%BDS.AI.ChatMessage{}, %{
+ conversation_id: conversation.id,
+ role: :assistant,
+ content: "Here is the chart.",
+ created_at: now + 3
+ })
+ )
+
+ {:ok, view, _html} = live_isolated(build_conn(), BDS.Desktop.ShellLive)
+
+ html =
+ render_click(view, "pin_sidebar_item", %{
+ "route" => "chat",
+ "id" => conversation.id,
+ "title" => conversation.title,
+ "subtitle" => conversation.model || "chat"
+ })
+
+ assert html =~ "count_posts"
+ assert html =~ "Here is the chart."
+ assert html =~ ~s(Assistant)
+
+ assert length(:binary.matches(html, ~s(Assistant))) == 1
+ end
+
test "chat editor marks user message text as compact" do
assert {:ok, conversation} = AI.start_chat(%{title: "Compact Chat", model: "gpt-4.1"})