diff --git a/libs/partners/openai/langchain_openai/chat_models/base.py b/libs/partners/openai/langchain_openai/chat_models/base.py
index a8702359b36..b01a560e232 100644
--- a/libs/partners/openai/langchain_openai/chat_models/base.py
+++ b/libs/partners/openai/langchain_openai/chat_models/base.py
@@ -3599,6 +3599,13 @@ def _construct_responses_api_payload(
                 }
             else:
                 pass
+
+    verbosity = payload.pop("verbosity", None)
+    if verbosity is not None:
+        if "text" not in payload:
+            payload["text"] = {"format": {"type": "text"}}
+        payload["text"]["verbosity"] = verbosity
+
     return payload
 
 
diff --git a/libs/partners/openai/pyproject.toml b/libs/partners/openai/pyproject.toml
index 3bc90cdf3fe..858cc45ca48 100644
--- a/libs/partners/openai/pyproject.toml
+++ b/libs/partners/openai/pyproject.toml
@@ -8,7 +8,7 @@ license = { text = "MIT" }
 requires-python = ">=3.9"
 dependencies = [
     "langchain-core<1.0.0,>=0.3.74",
-    "openai<2.0.0,>=1.86.0",
+    "openai<2.0.0,>=1.99.5",
     "tiktoken<1,>=0.7",
 ]
 name = "langchain-openai"
diff --git a/libs/partners/openai/tests/integration_tests/chat_models/test_responses_api.py b/libs/partners/openai/tests/integration_tests/chat_models/test_responses_api.py
index 32d3f199c85..4113b395f7a 100644
--- a/libs/partners/openai/tests/integration_tests/chat_models/test_responses_api.py
+++ b/libs/partners/openai/tests/integration_tests/chat_models/test_responses_api.py
@@ -674,28 +674,17 @@ def test_image_generation_multi_turn() -> None:
     assert set(tool_output2.keys()).issubset(expected_keys)
 
 
-@pytest.mark.xfail(
-    reason="verbosity parameter not yet supported by OpenAI Responses API"
-)
 def test_verbosity_parameter() -> None:
     """Test verbosity parameter with Responses API.
 
-    TODO: This test is expected to fail until OpenAI enables verbosity support
-    in the Responses API for available models. The parameter is properly implemented
-    in the codebase but the API currently returns 'Unknown parameter: verbosity'.
-    Remove @pytest.mark.xfail when OpenAI adds support.
+    Tests that the verbosity parameter works correctly with the OpenAI Responses API.
+
     """
-    llm = ChatOpenAI(
-        model=MODEL_NAME,
-        verbosity="medium",
-        use_responses_api=True,
-        output_version="responses/v1",
-    )
+    llm = ChatOpenAI(model=MODEL_NAME, verbosity="medium", use_responses_api=True)
     response = llm.invoke([HumanMessage(content="Hello, explain quantum computing.")])
 
     assert isinstance(response, AIMessage)
     assert response.content
-    # When verbosity works, we expect the response to respect the verbosity level
 
 
 @pytest.mark.vcr()
diff --git a/libs/partners/openai/tests/unit_tests/chat_models/test_base.py b/libs/partners/openai/tests/unit_tests/chat_models/test_base.py
index 73185790602..1d79f2a2d91 100644
--- a/libs/partners/openai/tests/unit_tests/chat_models/test_base.py
+++ b/libs/partners/openai/tests/unit_tests/chat_models/test_base.py
@@ -1200,7 +1200,8 @@ def test_verbosity_parameter_payload() -> None:
     messages = [{"role": "user", "content": "hello"}]
     payload = llm._get_request_payload(messages, stop=None)
 
-    assert payload["verbosity"] == "high"
+    assert payload["text"]["verbosity"] == "high"
+    assert payload["text"]["format"]["type"] == "text"
 
 
 def test_structured_output_old_model() -> None:
diff --git a/libs/partners/openai/uv.lock b/libs/partners/openai/uv.lock
index f626c1bacdc..7615c85c130 100644
--- a/libs/partners/openai/uv.lock
+++ b/libs/partners/openai/uv.lock
@@ -588,7 +588,7 @@ typing = [
 [package.metadata]
 requires-dist = [
     { name = "langchain-core", editable = "../../core" },
-    { name = "openai", specifier = ">=1.86.0,<2.0.0" },
+    { name = "openai", specifier = ">=1.99.5,<2.0.0" },
     { name = "tiktoken", specifier = ">=0.7,<1" },
 ]
 
@@ -995,7 +995,7 @@ wheels = [
 
 [[package]]
 name = "openai"
-version = "1.99.3"
+version = "1.99.5"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
     { name = "anyio" },
@@ -1007,9 +1007,9 @@ dependencies = [
     { name = "tqdm" },
     { name = "typing-extensions" },
 ]
-sdist = { url = "https://files.pythonhosted.org/packages/72/d3/c372420c8ca1c60e785fd8c19e536cea8f16b0cfdcdad6458e1d8884f2ea/openai-1.99.3.tar.gz", hash = "sha256:1a0e2910e4545d828c14218f2ac3276827c94a043f5353e43b9413b38b497897", size = 504932, upload-time = "2025-08-07T20:35:15.893Z" }
+sdist = { url = "https://files.pythonhosted.org/packages/2f/4a/16b1b6ee8a62cbfb59057f97f6d9b7bb5ce529047d80bc0b406f65dfdc48/openai-1.99.5.tar.gz", hash = "sha256:aa97ac3326cac7949c5e4ac0274c454c1d19c939760107ae0d3948fc26a924ca", size = 505144, upload-time = "2025-08-08T16:44:46.865Z" }
 wheels = [
-    { url = "https://files.pythonhosted.org/packages/92/bc/e52f49940b4e320629da7db09c90a2407a48c612cff397b4b41b7e58cdf9/openai-1.99.3-py3-none-any.whl", hash = "sha256:c786a03f6cddadb5ee42c6d749aa4f6134fe14fdd7d69a667e5e7ce7fd29a719", size = 785776, upload-time = "2025-08-07T20:35:13.653Z" },
+    { url = "https://files.pythonhosted.org/packages/e6/f2/2472ae020f5156a994710bf926a76915c71bc7b5debf7b81a11506ec8414/openai-1.99.5-py3-none-any.whl", hash = "sha256:4e870f9501b7c36132e2be13313ce3c4d6915a837e7a299c483aab6a6d4412e9", size = 786246, upload-time = "2025-08-08T16:44:45.062Z" },
 ]
 
 [[package]]