feat(langchain): reference model profiles for provider strategy (#33974)

libs/langchain_v1/langchain/agents/factory.py

@@ -63,6 +63,18 @@ if TYPE_CHECKING:
 
 STRUCTURED_OUTPUT_ERROR_TEMPLATE = "Error: {error}\n Please fix your mistakes."
 
+FALLBACK_MODELS_WITH_STRUCTURED_OUTPUT = [
+    # if langchain-model-profiles is not installed, these models are assumed to support
+    # structured output
+    "grok",
+    "gpt-5",
+    "gpt-4.1",
+    "gpt-4o",
+    "gpt-oss",
+    "o3-pro",
+    "o3-mini",
+]
+
 
 def _normalize_to_model_response(result: ModelResponse | AIMessage) -> ModelResponse:
     """Normalize middleware return value to ModelResponse."""
@@ -349,11 +361,13 @@ def _get_can_jump_to(middleware: AgentMiddleware[Any, Any], hook_name: str) -> l
     return []
 
 
-def _supports_provider_strategy(model: str | BaseChatModel) -> bool:
+def _supports_provider_strategy(model: str | BaseChatModel, tools: list | None = None) -> bool:
     """Check if a model supports provider-specific structured output.
 
     Args:
         model: Model name string or `BaseChatModel` instance.
+        tools: Optional list of tools provided to the agent. Needed because some models
+            don't support structured output together with tool calling.
 
     Returns:
         `True` if the model supports provider-specific structured output, `False` otherwise.
@@ -362,11 +376,26 @@ def _supports_provider_strategy(model: str | BaseChatModel) -> bool:
     if isinstance(model, str):
         model_name = model
     elif isinstance(model, BaseChatModel):
-        model_name = getattr(model, "model_name", None)
+        model_name = (
+            getattr(model, "model_name", None)
+            or getattr(model, "model", None)
+            or getattr(model, "model_id", "")
+        )
+        try:
+            model_profile = model.profile
+        except ImportError:
+            pass
+        else:
+            if (
+                model_profile.get("structured_output")
+                # We make an exception for Gemini models, which currently do not support
+                # simultaneous tool use with structured output
+                and not (tools and isinstance(model_name, str) and "gemini" in model_name.lower())
+            ):
+                return True
 
     return (
-        "grok" in model_name.lower()
-        or any(part in model_name for part in ["gpt-5", "gpt-4.1", "gpt-oss", "o3-pro", "o3-mini"])
+        any(part in model_name.lower() for part in FALLBACK_MODELS_WITH_STRUCTURED_OUTPUT)
         if model_name
         else False
     )
@@ -988,7 +1017,7 @@ def create_agent(  # noqa: PLR0915
         effective_response_format: ResponseFormat | None
         if isinstance(request.response_format, AutoStrategy):
             # User provided raw schema via AutoStrategy - auto-detect best strategy based on model
-            if _supports_provider_strategy(request.model):
+            if _supports_provider_strategy(request.model, tools=request.tools):
                 # Model supports provider strategy - use it
                 effective_response_format = ProviderStrategy(schema=request.response_format.schema)
             else:

libs/langchain_v1/pyproject.toml

@@ -57,6 +57,7 @@ test = [
     "pytest-mock",
     "syrupy>=4.0.2,<5.0.0",
     "toml>=0.10.2,<1.0.0",
+    "langchain-model-profiles",
     "langchain-tests",
     "langchain-openai",
 ]
@@ -75,6 +76,7 @@ test_integration = [
     "cassio>=0.1.0,<1.0.0",
     "langchainhub>=0.1.16,<1.0.0",
     "langchain-core",
+    "langchain-model-profiles",
     "langchain-text-splitters",
 ]
 
@@ -83,6 +85,7 @@ prerelease = "allow"
 
 [tool.uv.sources]
 langchain-core = { path = "../core", editable = true }
+langchain-model-profiles = { path = "../model-profiles", editable = true }
 langchain-tests = { path = "../standard-tests", editable = true }
 langchain-text-splitters = { path = "../text-splitters", editable = true }
 langchain-openai = { path = "../partners/openai", editable = true }

libs/langchain_v1/tests/unit_tests/agents/test_response_format.py

@@ -790,7 +790,7 @@ class TestDynamicModelWithResponseFormat:
         # Track which model is checked for provider strategy support
         calls = []
 
-        def mock_supports_provider_strategy(model) -> bool:
+        def mock_supports_provider_strategy(model, tools) -> bool:
             """Track which model is checked and return True for ProviderStrategy."""
             calls.append(model)
             return True

libs/langchain_v1/uv.lock

@@ -995,7 +995,7 @@ name = "exceptiongroup"
 version = "1.3.0"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
-    { name = "typing-extensions", marker = "python_full_version < '3.12'" },
+    { name = "typing-extensions", marker = "python_full_version < '3.11'" },
 ]
 sdist = { url = "https://files.pythonhosted.org/packages/0b/9f/a65090624ecf468cdca03533906e7c69ed7588582240cfe7cc9e770b50eb/exceptiongroup-1.3.0.tar.gz", hash = "sha256:b241f5885f560bc56a59ee63ca4c6a8bfa46ae4ad651af316d4e81817bb9fd88", size = 29749, upload-time = "2025-05-10T17:42:51.123Z" }
 wheels = [
@@ -1991,6 +1991,7 @@ lint = [
     { name = "ruff" },
 ]
 test = [
+    { name = "langchain-model-profiles" },
     { name = "langchain-openai" },
     { name = "langchain-tests" },
     { name = "pytest" },
@@ -2006,6 +2007,7 @@ test = [
 test-integration = [
     { name = "cassio" },
     { name = "langchain-core" },
+    { name = "langchain-model-profiles" },
     { name = "langchain-text-splitters" },
     { name = "langchainhub" },
     { name = "python-dotenv" },
@@ -2031,7 +2033,7 @@ requires-dist = [
     { name = "langchain-groq", marker = "extra == 'groq'" },
     { name = "langchain-huggingface", marker = "extra == 'huggingface'" },
     { name = "langchain-mistralai", marker = "extra == 'mistralai'" },
-    { name = "langchain-model-profiles", marker = "extra == 'model-profiles'" },
+    { name = "langchain-model-profiles", marker = "extra == 'model-profiles'", editable = "../model-profiles" },
     { name = "langchain-ollama", marker = "extra == 'ollama'" },
     { name = "langchain-openai", marker = "extra == 'openai'", editable = "../partners/openai" },
     { name = "langchain-perplexity", marker = "extra == 'perplexity'" },
@@ -2045,6 +2047,7 @@ provides-extras = ["model-profiles", "community", "anthropic", "openai", "azure-
 [package.metadata.requires-dev]
 lint = [{ name = "ruff", specifier = ">=0.12.2,<0.13.0" }]
 test = [
+    { name = "langchain-model-profiles", editable = "../model-profiles" },
     { name = "langchain-openai", editable = "../partners/openai" },
     { name = "langchain-tests", editable = "../standard-tests" },
     { name = "pytest", specifier = ">=8.0.0,<9.0.0" },
@@ -2060,6 +2063,7 @@ test = [
 test-integration = [
     { name = "cassio", specifier = ">=0.1.0,<1.0.0" },
     { name = "langchain-core", editable = "../core" },
+    { name = "langchain-model-profiles", editable = "../model-profiles" },
     { name = "langchain-text-splitters", editable = "../text-splitters" },
     { name = "langchainhub", specifier = ">=0.1.16,<1.0.0" },
     { name = "python-dotenv", specifier = ">=1.0.0,<2.0.0" },
@@ -2339,14 +2343,41 @@ wheels = [
 [[package]]
 name = "langchain-model-profiles"
 version = "0.0.4"
-source = { registry = "https://pypi.org/simple" }
+source = { editable = "../model-profiles" }
 dependencies = [
     { name = "tomli", marker = "python_full_version < '3.11'" },
     { name = "typing-extensions" },
 ]
-sdist = { url = "https://files.pythonhosted.org/packages/69/c3/cbadf3e884bfbd57f4604a68d67132ece45c3510a1ec710a5193b4b1a1af/langchain_model_profiles-0.0.4.tar.gz", hash = "sha256:b66909339c9175a6963e7fcdacae382b4773f8da04092b9dd64424b8e8b1f8c8", size = 145898, upload-time = "2025-11-10T17:08:44.875Z" }
-wheels = [
-    { url = "https://files.pythonhosted.org/packages/50/f0/a848f99a9d70f40c2f46c8d9465549adc6e8b678658be3ca11ce16287e24/langchain_model_profiles-0.0.4-py3-none-any.whl", hash = "sha256:7382b7feb2294ded84fe89b20a4d656f81f40c8f024233205b2c5507391ce1ba", size = 30419, upload-time = "2025-11-10T17:08:43.948Z" },
+
+[package.metadata]
+requires-dist = [
+    { name = "tomli", marker = "python_full_version < '3.11'", specifier = ">=2.0.0,<3.0.0" },
+    { name = "typing-extensions", specifier = ">=4.7.0,<5.0.0" },
+]
+
+[package.metadata.requires-dev]
+dev = [{ name = "httpx", specifier = ">=0.23.0,<1" }]
+lint = [
+    { name = "langchain", editable = "." },
+    { name = "ruff", specifier = ">=0.12.2,<0.13.0" },
+]
+test = [
+    { name = "langchain", extras = ["openai"], editable = "." },
+    { name = "langchain-core", editable = "../core" },
+    { name = "pytest", specifier = ">=8.0.0,<9.0.0" },
+    { name = "pytest-asyncio", specifier = ">=0.23.2,<2.0.0" },
+    { name = "pytest-cov", specifier = ">=4.0.0,<8.0.0" },
+    { name = "pytest-mock" },
+    { name = "pytest-socket", specifier = ">=0.6.0,<1.0.0" },
+    { name = "pytest-watcher", specifier = ">=0.2.6,<1.0.0" },
+    { name = "pytest-xdist", specifier = ">=3.6.1,<4.0.0" },
+    { name = "syrupy", specifier = ">=4.0.2,<5.0.0" },
+    { name = "toml", specifier = ">=0.10.2,<1.0.0" },
+]
+test-integration = [{ name = "langchain-core", editable = "../core" }]
+typing = [
+    { name = "mypy", specifier = ">=1.18.1,<1.19.0" },
+    { name = "types-toml", specifier = ">=0.10.8.20240310,<1.0.0.0" },
 ]
 
 [[package]]