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## Problem
When using `ChatOllama` with `create_react_agent`, agents would
sometimes terminate prematurely with empty responses when Ollama
returned `done_reason: 'load'` responses with no content. This caused
agents to return empty `AIMessage` objects instead of actual generated
text.
```python
from langchain_ollama import ChatOllama
from langgraph.prebuilt import create_react_agent
from langchain_core.messages import HumanMessage
llm = ChatOllama(model='qwen2.5:7b', temperature=0)
agent = create_react_agent(model=llm, tools=[])
result = agent.invoke(HumanMessage('Hello'), {"configurable": {"thread_id": "1"}})
# Before fix: AIMessage(content='', response_metadata={'done_reason': 'load'})
# Expected: AIMessage with actual generated content
```
## Root Cause
The `_iterate_over_stream` and `_aiterate_over_stream` methods treated
any response with `done: True` as final, regardless of `done_reason`.
When Ollama returns `done_reason: 'load'` with empty content, it
indicates the model was loaded but no actual generation occurred - this
should not be considered a complete response.
## Solution
Modified the streaming logic to skip responses when:
- `done: True`
- `done_reason: 'load'`
- Content is empty or contains only whitespace
This ensures agents only receive actual generated content while
preserving backward compatibility for load responses that do contain
content.
## Changes
- **`_iterate_over_stream`**: Skip empty load responses instead of
yielding them
- **`_aiterate_over_stream`**: Apply same fix to async streaming
- **Tests**: Added comprehensive test cases covering all edge cases
## Testing
All scenarios now work correctly:
- ✅ Empty load responses are skipped (fixes original issue)
- ✅ Load responses with actual content are preserved (backward
compatibility)
- ✅ Normal stop responses work unchanged
- ✅ Streaming behavior preserved
- ✅ `create_react_agent` integration fixed
Fixes #31482.
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