fix(openai): tool_call delta 重复携带 id/type，修复严格客户端兼容性

部分 OpenAI 兼容客户端要求每个 tool_call delta chunk 都包含 id 和 type
字段，否则会将后续 delta 视为无效。通过 block_to_tool_id 映射在
ContentBlockStart 时记录 tool_id，确保后续 ToolCallDelta 能正确回填。

src/core/api_format/conversion/normalizers/openai.py

@@ -796,6 +796,8 @@ class OpenAINormalizer(FormatNormalizer):
             tool_id = event.tool_id or ""
             tool_name = event.tool_name or ""
             tool_index = self._ensure_tool_call_index(ss, tool_id, event.block_index)
+            if tool_id:
+                ss.setdefault("block_to_tool_id", {})[int(event.block_index)] = str(tool_id)
             out.append(
                 base_chunk(
                     {
@@ -862,12 +864,22 @@ class OpenAINormalizer(FormatNormalizer):
             return out
 
         if isinstance(event, ToolCallDeltaEvent):
-            tool_index = self._ensure_tool_call_index(ss, event.tool_id, event.block_index)
-            # 后续 delta 只需 index + function.arguments；id/type 仅在 ContentBlockStartEvent 首次发送
+            tool_id = str(event.tool_id or "")
+            block_to_tool_id = ss.setdefault("block_to_tool_id", {})
+            if not tool_id:
+                tool_id = str(block_to_tool_id.get(int(event.block_index)) or "")
+            else:
+                block_to_tool_id[int(event.block_index)] = tool_id
+
+            tool_index = self._ensure_tool_call_index(ss, tool_id, event.block_index)
+            # 对严格客户端重复携带 id/type，避免它们把后续 delta 视为无效 tool_call。
             tc_delta: dict[str, Any] = {
                 "index": tool_index,
+                "type": "function",
                 "function": {"arguments": event.input_delta},
             }
+            if tool_id:
+                tc_delta["id"] = tool_id
             out.append(base_chunk({"tool_calls": [tc_delta]}))
             return out
 

tests/core/api_format/conversion/test_cli_conversion.py

@@ -857,15 +857,21 @@ def test_tool_call_stream_index_stable_across_deltas() -> None:
 
     # 收集所有 tool_calls chunk
     tc_indices: list[int] = []
+    tc_ids: list[str] = []
     for event in all_events:
         for choice in event.get("choices", []):
             tcs = choice.get("delta", {}).get("tool_calls")
             if isinstance(tcs, list):
                 for tc in tcs:
                     tc_indices.append(tc["index"])
+                    tc_ids.append(str(tc.get("id") or ""))
 
     assert len(tc_indices) >= 2, f"expected at least 2 tool_call chunks, got {len(tc_indices)}"
     # 同一个 tool call 的所有 chunk 必须使用相同的 index
     assert all(
         idx == tc_indices[0] for idx in tc_indices
     ), f"tool_call index should be stable, got: {tc_indices}"
+    assert all(tc_id == "fc_001" for tc_id in tc_ids), (
+        "tool_call id should be repeated on every delta for strict OpenAI-compatible clients, "
+        f"got: {tc_ids}"
+    )