Add Claude Fable 5 across Anthropic, Bedrock, Vertex AI, and Azure AI

litellm/constants.py

@@ -1158,6 +1158,7 @@
     "openai.gpt-oss-120b-1:0",
     "anthropic.claude-haiku-4-5-20251001-v1:0",
     "anthropic.claude-sonnet-4-5-20250929-v1:0",
+    "anthropic.claude-fable-5",
     "anthropic.claude-opus-4-8",
     "anthropic.claude-opus-4-7",
     "anthropic.claude-opus-4-6-v1:0",

litellm/llms/anthropic/chat/transformation.py

@@ -1455,10 +1455,15 @@ def map_openai_params(  # noqa: PLR0915
                 _value = self._map_stop_sequences(value)
                 if _value is not None:
                     optional_params["stop_sequences"] = _value
-            elif param == "temperature":
-                optional_params["temperature"] = value
-            elif param == "top_p":
-                optional_params["top_p"] = value
+            elif param == "temperature" or param == "top_p":
+                AnthropicConfig._apply_sampling_param(
+                    optional_params=optional_params,
+                    model=model,
+                    param=param,
+                    value=value,
+                    drop_params=drop_params,
+                    output_key=param,
+                )
             elif param == "response_format" and isinstance(value, dict):
                 if any(
                     substring in model
@@ -1975,6 +1980,20 @@ def transform_request(
         optional_params.pop("is_vertex_request", None)
         optional_params.pop("client_metadata", None)
 
+        # ``top_k`` is a provider-specific kwarg that bypasses
+        # ``map_openai_params``; gate it here, the single boundary shared by
+        # the direct Anthropic, Bedrock invoke, Vertex, and Azure paths.
+        top_k = optional_params.pop("top_k", None)
+        if top_k is not None:
+            AnthropicConfig._apply_sampling_param(
+                optional_params=optional_params,
+                model=model,
+                param="top_k",
+                value=top_k,
+                drop_params=litellm_params.get("drop_params") is True,
+                output_key="top_k",
+            )
+
         data = {
             "model": model,
             "messages": anthropic_messages,

litellm/llms/anthropic/common_utils.py

@@ -272,23 +272,68 @@ def _is_claude_4_7_model(model: str) -> bool:
         )
 
     @staticmethod
-    def _supports_model_capability(model: str, key: str) -> bool:
-        """Check a boolean capability ``key`` in the model map.
+    def _supports_sampling_params(model: str) -> bool:
+        """Claude 4.7+ (Opus 4.7/4.8, Fable 5) removed sampling params: the API
+        rejects ``top_p``, ``top_k``, and any ``temperature`` other than 1 with
+        a 400 ("`temperature` is deprecated for this model").
+
+        Driven by the ``supports_sampling_params`` flag in the model map; the
+        name check remains only as a fallback for provider-routed ids whose
+        map entries predate the flag."""
+        flag = AnthropicModelInfo._get_model_capability(
+            model, "supports_sampling_params"
+        )
+        if flag is not None:
+            return flag
+        model_lower = model.lower()
+        return not any(
+            v in model_lower
+            for v in (
+                "fable",
+                "opus-4-7",
+                "opus_4_7",
+                "opus-4.7",
+                "opus_4.7",
+                "opus-4-8",
+                "opus_4_8",
+                "opus-4.8",
+                "opus_4.8",
+            )
+        )
 
-        Strips bedrock/vertex prefixes so a provider-routed Claude still
-        resolves to the Anthropic model-map entry.
-        """
-        from litellm.utils import _supports_factory
+    @staticmethod
+    def _apply_sampling_param(
+        optional_params: dict,
+        model: str,
+        param: str,
+        value: Any,
+        drop_params: bool,
+        output_key: str,
+    ) -> None:
+        """Forward ``temperature``/``top_p``/``top_k`` to
+        ``optional_params[output_key]`` unless the model removed sampling
+        params, in which case drop the param (with drop_params) or raise a
+        clean client-side 400."""
+        if AnthropicModelInfo._supports_sampling_params(model) or (
+            param == "temperature" and value == 1
+        ):
+            optional_params[output_key] = value
+        elif not (litellm.drop_params or drop_params):
+            supported_hint = (
+                "Only temperature=1 is supported. " if param == "temperature" else ""
+            )
+            raise litellm.utils.UnsupportedParamsError(
+                message=(
+                    f"{model} does not support {param}={value}. {supported_hint}"
+                    "To drop unsupported params, set `litellm.drop_params = True`."
+                ),
+                status_code=400,
+            )
 
-        try:
-            if _supports_factory(
-                model=model,
-                custom_llm_provider="anthropic",
-                key=key,
-            ):
-                return True
-        except Exception:
-            pass
+    @staticmethod
+    def _model_map_lookup_candidates(model: str) -> List[str]:
+        """Model-map keys to try for ``model``, stripping bedrock/vertex
+        prefixes so a provider-routed Claude still resolves to its entry."""
         candidates = [model]
         for prefix in (
             "bedrock/converse/",
@@ -307,15 +352,40 @@ def _supports_model_capability(model: str, key: str) -> bool:
                 candidates.append(f"bedrock/{base}")
         except Exception:
             pass
+        return candidates
+
+    @staticmethod
+    def _get_model_capability(model: str, key: str) -> Optional[bool]:
+        """Read boolean capability ``key`` from the model map, or None when
+        no entry declares it."""
         try:
-            for cand in candidates:
-                if cand in litellm.model_cost and (
-                    litellm.model_cost[cand].get(key) is True
-                ):
-                    return True
+            for cand in AnthropicModelInfo._model_map_lookup_candidates(model):
+                value = litellm.model_cost.get(cand, {}).get(key)
+                if isinstance(value, bool):
+                    return value
         except Exception:
             pass
-        return False
+        return None
+
+    @staticmethod
+    def _supports_model_capability(model: str, key: str) -> bool:
+        """Check a boolean capability ``key`` in the model map.
+
+        Strips bedrock/vertex prefixes so a provider-routed Claude still
+        resolves to the Anthropic model-map entry.
+        """
+        from litellm.utils import _supports_factory
+
+        try:
+            if _supports_factory(
+                model=model,
+                custom_llm_provider="anthropic",
+                key=key,
+            ):
+                return True
+        except Exception:
+            pass
+        return AnthropicModelInfo._get_model_capability(model, key) is True
 
     @staticmethod
     def _is_adaptive_thinking_model(model: str) -> bool:

litellm/llms/bedrock/chat/converse_transformation.py

@@ -920,10 +920,15 @@ def map_openai_params(
                         continue
                     value = [value]
                 optional_params["stopSequences"] = value
-            if param == "temperature":
-                optional_params["temperature"] = value
-            if param == "top_p":
-                optional_params["topP"] = value
+            if param == "temperature" or param == "top_p":
+                AnthropicConfig._apply_sampling_param(
+                    optional_params=optional_params,
+                    model=model,
+                    param=param,
+                    value=value,
+                    drop_params=drop_params,
+                    output_key="topP" if param == "top_p" else param,
+                )
             if param == "tools" and isinstance(value, list):
                 self._apply_tool_call_transformation(
                     tools=cast(List[OpenAIChatCompletionToolParam], value),
@@ -1221,7 +1226,9 @@ def _transform_inference_params(self, inference_params: dict) -> InferenceConfig
             inference_params["topK"] = inference_params.pop("top_k")
         return InferenceConfig(**inference_params)
 
-    def _handle_top_k_value(self, model: str, inference_params: dict) -> dict:
+    def _handle_top_k_value(
+        self, model: str, inference_params: dict, drop_params: bool = False
+    ) -> dict:
         base_model = BedrockModelInfo.get_base_model(model)
 
         val_top_k = None
@@ -1230,16 +1237,25 @@ def _handle_top_k_value(self, model: str, inference_params: dict) -> dict:
         elif "top_k" in inference_params:
             val_top_k = inference_params.pop("top_k")
 
-        if val_top_k:
+        if val_top_k is not None:
             if base_model.startswith("anthropic"):
-                return {"top_k": val_top_k}
+                top_k_params: dict = {}
+                AnthropicConfig._apply_sampling_param(
+                    optional_params=top_k_params,
+                    model=model,
+                    param="top_k",
+                    value=val_top_k,
+                    drop_params=drop_params,
+                    output_key="top_k",
+                )
+                return top_k_params
             if base_model.startswith("amazon.nova"):
                 return {"inferenceConfig": {"topK": val_top_k}}
 
         return {}
 
     def _prepare_request_params(
-        self, optional_params: dict, model: str
+        self, optional_params: dict, model: str, drop_params: bool = False
     ) -> Tuple[dict, dict, dict, Optional[OutputConfigBlock]]:
         """Prepare and separate request parameters."""
         # Consume the internal ``_output_config_normalized`` marker set by
@@ -1338,7 +1354,7 @@ def _prepare_request_params(
 
         # Only set the topK value in for models that support it
         additional_request_params.update(
-            self._handle_top_k_value(model, inference_params)
+            self._handle_top_k_value(model, inference_params, drop_params)
         )
 
         # Filter out internal/MCP-related parameters that shouldn't be sent to the API
@@ -1572,6 +1588,7 @@ def _transform_request_helper(
         optional_params: dict,
         messages: Optional[List[AllMessageValues]] = None,
         headers: Optional[dict] = None,
+        drop_params: bool = False,
     ) -> CommonRequestObject:
         ## VALIDATE REQUEST
         """
@@ -1618,7 +1635,7 @@ def _transform_request_helper(
             additional_request_params,
             request_metadata,
             output_config,
-        ) = self._prepare_request_params(optional_params, model)
+        ) = self._prepare_request_params(optional_params, model, drop_params)
 
         original_tools = inference_params.pop("tools", [])
 
@@ -1701,6 +1718,7 @@ async def _async_transform_request(
             optional_params=optional_params,
             messages=messages,
             headers=headers,
+            drop_params=litellm_params.get("drop_params") is True,
         )
 
         bedrock_messages = (
@@ -1758,6 +1776,7 @@ def _transform_request(
             optional_params=optional_params,
             messages=messages,
             headers=headers,
+            drop_params=litellm_params.get("drop_params") is True,
         )
 
         ## TRANSFORMATION ##