community: add truncation params when an openai assistant's run is created

libs/community/langchain_community/agents/openai_assistant/base.py

@@ -543,11 +543,16 @@ def _create_run(self, input: dict) -> Any:
         Returns:
             Any: The created run object.
         """
-        params = {
-            k: v
-            for k, v in input.items()
-            if k in ("instructions", "model", "tools", "tool_resources", "run_metadata")
-        }
+        allowed_assistant_params = (
+            "instructions",
+            "model",
+            "tools",
+            "tool_resources",
+            "run_metadata",
+            "truncation_strategy",
+            "max_prompt_tokens",
+        )
+        params = {k: v for k, v in input.items() if k in allowed_assistant_params}
         return self.client.beta.threads.runs.create(
             input["thread_id"],
             assistant_id=self.assistant_id,

libs/community/tests/unit_tests/agents/test_openai_assistant.py

@@ -0,0 +1,39 @@
+from typing import Any
+from unittest.mock import AsyncMock, MagicMock
+
+import pytest
+
+from langchain_community.agents.openai_assistant import OpenAIAssistantV2Runnable
+
+
+def _create_mock_client(*args: Any, use_async: bool = False, **kwargs: Any) -> Any:
+    client = AsyncMock() if use_async else MagicMock()
+    client.beta.threads.runs.create = MagicMock(return_value=None)  # type: ignore
+    return client
+
+
+@pytest.mark.requires("openai")
+def test_set_run_truncation_params() -> None:
+    client = _create_mock_client()
+
+    assistant = OpenAIAssistantV2Runnable(assistant_id="assistant_xyz", client=client)
+    input = {
+        "content": "AI question",
+        "thread_id": "thread_xyz",
+        "instructions": "You're a helpful assistant; answer questions as best you can.",
+        "model": "gpt-4o",
+        "max_prompt_tokens": 2000,
+        "truncation_strategy": {"type": "last_messages", "last_messages": 10},
+    }
+    expected_response = {
+        "assistant_id": "assistant_xyz",
+        "instructions": "You're a helpful assistant; answer questions as best you can.",
+        "model": "gpt-4o",
+        "max_prompt_tokens": 2000,
+        "truncation_strategy": {"type": "last_messages", "last_messages": 10},
+    }
+
+    assistant._create_run(input=input)
+    _, kwargs = client.beta.threads.runs.create.call_args
+
+    assert kwargs == expected_response