fix(provider): preserve streamed Codex output when response.completed.output is empty (#1928)

* fix: preserve streamed Codex output items

* fix: prefer completed Codex output over streamed placeholders

backend/packages/harness/deerflow/models/openai_codex_provider.py

@@ -216,18 +216,48 @@ class CodexChatModel(BaseChatModel):
     def _stream_response(self, headers: dict, payload: dict) -> dict:
         """Stream SSE from Codex API and collect the final response."""
         completed_response = None
+        streamed_output_items: dict[int, dict[str, Any]] = {}
 
         with httpx.Client(timeout=300) as client:
             with client.stream("POST", f"{CODEX_BASE_URL}/responses", headers=headers, json=payload) as resp:
                 resp.raise_for_status()
                 for line in resp.iter_lines():
                     data = self._parse_sse_data_line(line)
-                    if data and data.get("type") == "response.completed":
+                    if not data:
+                        continue
+
+                    event_type = data.get("type")
+                    if event_type == "response.output_item.done":
+                        output_index = data.get("output_index")
+                        output_item = data.get("item")
+                        if isinstance(output_index, int) and isinstance(output_item, dict):
+                            streamed_output_items[output_index] = output_item
+                    elif event_type == "response.completed":
                         completed_response = data["response"]
 
         if not completed_response:
             raise RuntimeError("Codex API stream ended without response.completed event")
 
+        # ChatGPT Codex can emit the final assistant content only in stream events.
+        # When response.completed arrives, response.output may still be empty.
+        if streamed_output_items:
+            merged_output = []
+            response_output = completed_response.get("output")
+            if isinstance(response_output, list):
+                merged_output = list(response_output)
+
+            max_index = max(max(streamed_output_items), len(merged_output) - 1)
+            if max_index >= 0 and len(merged_output) <= max_index:
+                merged_output.extend([None] * (max_index + 1 - len(merged_output)))
+
+            for output_index, output_item in streamed_output_items.items():
+                existing_item = merged_output[output_index]
+                if not isinstance(existing_item, dict):
+                    merged_output[output_index] = output_item
+
+            completed_response = dict(completed_response)
+            completed_response["output"] = [item for item in merged_output if isinstance(item, dict)]
+
         return completed_response
 
     @staticmethod

backend/tests/test_cli_auth_providers.py

@@ -5,6 +5,7 @@ import json
 import pytest
 from langchain_core.messages import HumanMessage, SystemMessage
 
+from deerflow.models import openai_codex_provider as codex_provider_module
 from deerflow.models.claude_provider import ClaudeChatModel
 from deerflow.models.credential_loader import CodexCliCredential
 from deerflow.models.openai_codex_provider import CodexChatModel
@@ -147,3 +148,124 @@ def test_codex_provider_parses_valid_tool_arguments(monkeypatch):
     )
 
     assert result.generations[0].message.tool_calls == [{"name": "bash", "args": {"cmd": "pwd"}, "id": "tc-1", "type": "tool_call"}]
+
+
+class _FakeResponseStream:
+    def __init__(self, lines: list[str]):
+        self._lines = lines
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc, tb):
+        return False
+
+    def raise_for_status(self):
+        return None
+
+    def iter_lines(self):
+        yield from self._lines
+
+
+class _FakeHttpxClient:
+    def __init__(self, lines: list[str], *_args, **_kwargs):
+        self._lines = lines
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc, tb):
+        return False
+
+    def stream(self, *_args, **_kwargs):
+        return _FakeResponseStream(self._lines)
+
+
+def test_codex_provider_merges_streamed_output_items_when_completed_output_is_empty(monkeypatch):
+    monkeypatch.setattr(
+        CodexChatModel,
+        "_load_codex_auth",
+        lambda self: CodexCliCredential(access_token="token", account_id="acct"),
+    )
+
+    lines = [
+        'data: {"type":"response.output_item.done","output_index":0,"item":{"type":"message","content":[{"type":"output_text","text":"Hello from stream"}]}}',
+        'data: {"type":"response.completed","response":{"model":"gpt-5.4","output":[],"usage":{"input_tokens":1,"output_tokens":2,"total_tokens":3}}}',
+    ]
+
+    monkeypatch.setattr(
+        codex_provider_module.httpx,
+        "Client",
+        lambda *args, **kwargs: _FakeHttpxClient(lines, *args, **kwargs),
+    )
+
+    model = CodexChatModel()
+    response = model._stream_response(headers={}, payload={})
+    parsed = model._parse_response(response)
+
+    assert response["output"] == [
+        {
+            "type": "message",
+            "content": [{"type": "output_text", "text": "Hello from stream"}],
+        }
+    ]
+    assert parsed.generations[0].message.content == "Hello from stream"
+
+
+def test_codex_provider_orders_streamed_output_items_by_output_index(monkeypatch):
+    monkeypatch.setattr(
+        CodexChatModel,
+        "_load_codex_auth",
+        lambda self: CodexCliCredential(access_token="token", account_id="acct"),
+    )
+
+    lines = [
+        'data: {"type":"response.output_item.done","output_index":1,"item":{"type":"message","content":[{"type":"output_text","text":"Second"}]}}',
+        'data: {"type":"response.output_item.done","output_index":0,"item":{"type":"message","content":[{"type":"output_text","text":"First"}]}}',
+        'data: {"type":"response.completed","response":{"model":"gpt-5.4","output":[],"usage":{}}}',
+    ]
+
+    monkeypatch.setattr(
+        codex_provider_module.httpx,
+        "Client",
+        lambda *args, **kwargs: _FakeHttpxClient(lines, *args, **kwargs),
+    )
+
+    model = CodexChatModel()
+    response = model._stream_response(headers={}, payload={})
+
+    assert [item["content"][0]["text"] for item in response["output"]] == [
+        "First",
+        "Second",
+    ]
+
+
+def test_codex_provider_preserves_completed_output_when_stream_only_has_placeholder(monkeypatch):
+    monkeypatch.setattr(
+        CodexChatModel,
+        "_load_codex_auth",
+        lambda self: CodexCliCredential(access_token="token", account_id="acct"),
+    )
+
+    lines = [
+        'data: {"type":"response.output_item.added","output_index":0,"item":{"type":"message","status":"in_progress","content":[]}}',
+        'data: {"type":"response.completed","response":{"model":"gpt-5.4","output":[{"type":"message","content":[{"type":"output_text","text":"Final from completed"}]}],"usage":{}}}',
+    ]
+
+    monkeypatch.setattr(
+        codex_provider_module.httpx,
+        "Client",
+        lambda *args, **kwargs: _FakeHttpxClient(lines, *args, **kwargs),
+    )
+
+    model = CodexChatModel()
+    response = model._stream_response(headers={}, payload={})
+    parsed = model._parse_response(response)
+
+    assert response["output"] == [
+        {
+            "type": "message",
+            "content": [{"type": "output_text", "text": "Final from completed"}],
+        }
+    ]
+    assert parsed.generations[0].message.content == "Final from completed"