refactor(anthropic): drive adaptive-thinking gate via supports_adaptive_thinking flag

Three of greptile's open comments on #27074 (P2 converse:512, P1
databricks:361, and the underlying capability-flag policy rule) flagged
the same pattern: _is_claude_4_6_model(...) or _is_claude_4_7_model(...)
used inline as a runtime 'is this an adaptive-thinking model?' check.
That requires a code release each time a new adaptive Claude lands.

Consolidate the inline gating to AnthropicModelInfo._is_adaptive_thinking_model,
and switch the helper itself to read a new supports_adaptive_thinking
flag from `model_prices_and_context_window.json` via `_supports_factory`,
falling back to the family pattern only when the model-map entry doesn't
carry the flag (preserves OpenRouter / Vercel / Bedrock-prefixed variants
that route through the same code path with non-canonical ids).

Adds `supports_adaptive_thinking: true` to the four 4.6/4.7 anthropic
entries (opus-4-6 + dated, opus-4-7 + dated, sonnet-4-6). Bedrock-prefixed
and Vertex-prefixed entries don't need the flag because both fall back
through the family pattern (the helper short-circuits early on True from
either path) and the bedrock/vertex Claude IDs all match the existing
opus-4-{6,7} / sonnet-4-{6,7} pattern.

Affected call sites:

- `bedrock/chat/converse_transformation.py:_handle_reasoning_effort_parameter`
- `anthropic/chat/transformation.py:_map_reasoning_effort`
- `anthropic/chat/transformation.py:map_openai_params` (output_config branch)
- `databricks/chat/transformation.py:map_openai_params` (output_config branch)

The remaining `_is_claude_4_6_model` / `_is_claude_4_7_model` references
in `AnthropicConfig._validate_effort_for_model` and
`AnthropicConfig.get_supported_openai_params` are intentionally retained:
they're per-model gating fallbacks for variants whose model-map entries
don't yet carry the `supports_max_reasoning_effort` /
`supports_reasoning` flag. Those are documented in-place.

Tests: 537 anthropic/bedrock/databricks/vertex/messages tests pass.

Co-authored-by: Mateo Wang <mateo-berri@users.noreply.github.com>

litellm/llms/anthropic/chat/transformation.py

@@ -920,9 +920,7 @@ class AnthropicConfig(AnthropicModelInfo, BaseConfig):
         """
         if reasoning_effort is None or reasoning_effort == "none":
             return None
-        if AnthropicConfig._is_claude_4_6_model(
+        if AnthropicConfig._is_adaptive_thinking_model(model):
-            model
-        ) or AnthropicConfig._is_claude_4_7_model(model):
             return AnthropicThinkingParam(
                 type="adaptive",
             )
@@ -1262,11 +1260,12 @@ class AnthropicConfig(AnthropicModelInfo, BaseConfig):
                     optional_params.pop("output_config", None)
                 else:
                     optional_params["thinking"] = mapped_thinking
-                    # For Claude 4.6+ models, effort is controlled via output_config,
+                    # For Claude 4.6+ adaptive-thinking models, effort is
-                    # not thinking budget_tokens. Map reasoning_effort to output_config.
+                    # controlled via ``output_config``, not
-                    if AnthropicConfig._is_claude_4_6_model(
+                    # ``thinking.budget_tokens``. Driven by
-                        model
+                    # ``supports_adaptive_thinking`` in the model map so
-                    ) or AnthropicConfig._is_claude_4_7_model(model):
+                    # adding a new adaptive Claude is a model-map-only change.
+                    if AnthropicConfig._is_adaptive_thinking_model(model):
                         # ``_map_reasoning_effort`` returns ``type=adaptive``
                         # for any string on adaptive models without checking
                         # the value, so reject unmapped efforts here (matching

litellm/llms/anthropic/common_utils.py

@@ -273,7 +273,26 @@ class AnthropicModelInfo(BaseLLMModelInfo):
 
     @staticmethod
     def _is_adaptive_thinking_model(model: str) -> bool:
-        """Claude 4.6+ models use adaptive thinking with output_config effort."""
+        """Claude 4.6+ models use adaptive thinking with ``output_config.effort``.
+
+        Driven by the ``supports_adaptive_thinking`` flag in
+        ``model_prices_and_context_window.json`` so that adding a new
+        adaptive-thinking model is a pure model-map change. Falls back to
+        the family-pattern check for OpenRouter / Vercel / Bedrock /
+        provider-prefixed variants whose model-map entries don't (yet)
+        carry the flag.
+        """
+        from litellm.utils import _supports_factory
+
+        try:
+            if _supports_factory(
+                model=model,
+                custom_llm_provider=None,
+                key="supports_adaptive_thinking",
+            ):
+                return True
+        except Exception:
+            pass
         return AnthropicModelInfo._is_claude_4_6_model(
             model
         ) or AnthropicModelInfo._is_claude_4_7_model(model)

litellm/llms/bedrock/chat/converse_transformation.py

@@ -478,14 +478,15 @@ class AmazonConverseConfig(BaseConfig):
                 optional_params.pop("output_config", None)
             else:
                 optional_params["thinking"] = mapped_thinking
-                # Adaptive-thinking models (Claude 4.6 / 4.7) take the tier
+                # Adaptive-thinking models (Claude 4.6 / 4.7+) take the
-                # via output_config.effort. Mirror the mapping used by
+                # tier via ``output_config.effort``. Mirror the mapping
-                # AnthropicConfig.map_openai_params and apply the same
+                # used by ``AnthropicConfig.map_openai_params`` and apply
-                # validation rules so unmapped/garbage efforts surface as a
+                # the same validation rules so unmapped/garbage efforts
-                # 400 instead of being silently flattened on the wire.
+                # surface as a 400 instead of being silently flattened on
-                if AnthropicConfig._is_claude_4_6_model(
+                # the wire. Driven by ``supports_adaptive_thinking`` in
-                    model
+                # ``model_prices_and_context_window.json`` so a future
-                ) or AnthropicConfig._is_claude_4_7_model(model):
+                # adaptive Claude release lands as a model-map change.
+                if AnthropicConfig._is_adaptive_thinking_model(model):
                     # Use ``.get()`` without a fallback so unmapped efforts
                     # (e.g. ``"disabled"``) surface as a clean 400 here
                     # rather than leaking the raw garbage string through to

litellm/llms/databricks/chat/transformation.py

@@ -350,15 +350,17 @@ class DatabricksConfig(DatabricksBase, OpenAILikeChatConfig, AnthropicConfig):
                 optional_params.pop("output_config", None)
             else:
                 optional_params["thinking"] = mapped_thinking
-                # For Claude 4.6/4.7 adaptive models, ``_map_reasoning_effort``
+                # For Claude 4.6+ adaptive models, ``_map_reasoning_effort``
                 # returns ``type=adaptive`` for ANY non-None / non-"none"
                 # string without validating the value, so reject unmapped
                 # efforts here and set ``output_config.effort`` (matching the
                 # Anthropic native / Bedrock Converse / Bedrock Invoke /
-                # /v1/messages paths).
+                # /v1/messages paths). Driven by ``supports_adaptive_thinking``
-                if AnthropicConfig._is_claude_4_6_model(
+                # in the model map so future adaptive Claudes land via a
-                    model
+                # model-map update rather than a code release — the
-                ) or AnthropicConfig._is_claude_4_7_model(model):
+                # Anthropic-native and Bedrock routes already use the same
+                # helper, so all three paths stay in lock-step.
+                if AnthropicConfig._is_adaptive_thinking_model(model):
                     # ``reasoning_effort_value`` comes from ``non_default_params``
                     # so its static type is ``Any | None``. Narrow to ``str`` for
                     # the mapping lookup; non-strings fall through to the

model_prices_and_context_window.json

@@ -9228,6 +9228,7 @@
             "search_context_size_low": 0.01,
             "search_context_size_medium": 0.01
         },
+        "supports_adaptive_thinking": true,
         "supports_assistant_prefill": true,
         "supports_computer_use": true,
         "supports_function_calling": true,
@@ -9421,6 +9422,7 @@
             "search_context_size_low": 0.01,
             "search_context_size_medium": 0.01
         },
+        "supports_adaptive_thinking": true,
         "supports_assistant_prefill": false,
         "supports_computer_use": true,
         "supports_function_calling": true,
@@ -9454,6 +9456,7 @@
             "search_context_size_low": 0.01,
             "search_context_size_medium": 0.01
         },
+        "supports_adaptive_thinking": true,
         "supports_assistant_prefill": false,
         "supports_computer_use": true,
         "supports_function_calling": true,
@@ -9487,6 +9490,7 @@
             "search_context_size_low": 0.01,
             "search_context_size_medium": 0.01
         },
+        "supports_adaptive_thinking": true,
         "supports_assistant_prefill": false,
         "supports_computer_use": true,
         "supports_function_calling": true,
@@ -9521,6 +9525,7 @@
             "search_context_size_low": 0.01,
             "search_context_size_medium": 0.01
         },
+        "supports_adaptive_thinking": true,
         "supports_assistant_prefill": false,
         "supports_computer_use": true,
         "supports_function_calling": true,