diff --git a/src/anthropic/lib/streaming/_beta_messages.py b/src/anthropic/lib/streaming/_beta_messages.py
index a760dcea..35c5ccc6 100644
--- a/src/anthropic/lib/streaming/_beta_messages.py
+++ b/src/anthropic/lib/streaming/_beta_messages.py
@@ -464,13 +464,14 @@ def accumulate_event(
         raise RuntimeError(f'Unexpected event order, got {event.type} before "message_start"')
 
     if event.type == "content_block_start":
-        # TODO: check index
-        current_snapshot.content.append(
-            cast(
-                Any,  # Pydantic does not support generic unions at runtime
-                construct_type(type_=ParsedBetaContentBlock, value=event.content_block.to_dict()),
-            ),
+        new_block = cast(
+            Any,  # Pydantic does not support generic unions at runtime
+            construct_type(type_=ParsedBetaContentBlock, value=event.content_block.to_dict()),
         )
+        if event.index >= len(current_snapshot.content):
+            current_snapshot.content.extend([None] * (event.index - len(current_snapshot.content) + 1))  # type: ignore[arg-type]
+
+        current_snapshot.content[event.index] = new_block
     elif event.type == "content_block_delta":
         content = current_snapshot.content[event.index]
         if event.delta.type == "text_delta":
@@ -536,5 +537,7 @@ def accumulate_event(
             current_snapshot.usage.cache_read_input_tokens = event.usage.cache_read_input_tokens
         if event.usage.server_tool_use is not None:
             current_snapshot.usage.server_tool_use = event.usage.server_tool_use
+        if event.usage.thinking_tokens is not None:
+            current_snapshot.usage.thinking_tokens = event.usage.thinking_tokens
 
     return current_snapshot
diff --git a/src/anthropic/lib/streaming/_messages.py b/src/anthropic/lib/streaming/_messages.py
index 857f9734..96e545bc 100644
--- a/src/anthropic/lib/streaming/_messages.py
+++ b/src/anthropic/lib/streaming/_messages.py
@@ -424,13 +424,14 @@ def accumulate_event(
         raise RuntimeError(f'Unexpected event order, got {event.type} before "message_start"')
 
     if event.type == "content_block_start":
-        # TODO: check index
-        current_snapshot.content.append(
-            cast(
-                ContentBlock,
-                construct_type(type_=ContentBlock, value=event.content_block.model_dump()),
-            ),
+        new_block = cast(
+            ContentBlock,
+            construct_type(type_=ContentBlock, value=event.content_block.model_dump()),
         )
+        if event.index >= len(current_snapshot.content):
+            current_snapshot.content.extend([None] * (event.index - len(current_snapshot.content) + 1))  # type: ignore[arg-type]
+
+        current_snapshot.content[event.index] = new_block
     elif event.type == "content_block_delta":
         content = current_snapshot.content[event.index]
         if event.delta.type == "text_delta":
@@ -480,5 +481,7 @@ def accumulate_event(
             current_snapshot.usage.cache_read_input_tokens = event.usage.cache_read_input_tokens
         if event.usage.server_tool_use is not None:
             current_snapshot.usage.server_tool_use = event.usage.server_tool_use
+        if event.usage.thinking_tokens is not None:
+            current_snapshot.usage.thinking_tokens = event.usage.thinking_tokens
 
     return current_snapshot
diff --git a/src/anthropic/types/beta/beta_message_delta_usage.py b/src/anthropic/types/beta/beta_message_delta_usage.py
index 11c815d8..6fbea23d 100644
--- a/src/anthropic/types/beta/beta_message_delta_usage.py
+++ b/src/anthropic/types/beta/beta_message_delta_usage.py
@@ -23,3 +23,6 @@ class BetaMessageDeltaUsage(BaseModel):
 
     server_tool_use: Optional[BetaServerToolUsage] = None
     """The number of server tool requests."""
+
+    thinking_tokens: Optional[int] = None
+    """The cumulative number of tokens used for thinking."""
diff --git a/src/anthropic/types/beta/beta_usage.py b/src/anthropic/types/beta/beta_usage.py
index 387d24c1..c14524c8 100644
--- a/src/anthropic/types/beta/beta_usage.py
+++ b/src/anthropic/types/beta/beta_usage.py
@@ -29,5 +29,8 @@ class BetaUsage(BaseModel):
     server_tool_use: Optional[BetaServerToolUsage] = None
     """The number of server tool requests."""
 
+    thinking_tokens: Optional[int] = None
+    """The number of tokens used for thinking."""
+
     service_tier: Optional[Literal["standard", "priority", "batch"]] = None
     """If the request used the priority, standard, or batch tier."""
diff --git a/src/anthropic/types/message_delta_usage.py b/src/anthropic/types/message_delta_usage.py
index 11bd49d7..3e4dd9dd 100644
--- a/src/anthropic/types/message_delta_usage.py
+++ b/src/anthropic/types/message_delta_usage.py
@@ -23,3 +23,6 @@ class MessageDeltaUsage(BaseModel):
 
     server_tool_use: Optional[ServerToolUsage] = None
     """The number of server tool requests."""
+
+    thinking_tokens: Optional[int] = None
+    """The cumulative number of tokens used for thinking."""
diff --git a/src/anthropic/types/usage.py b/src/anthropic/types/usage.py
index 21f7037c..4a14eafb 100644
--- a/src/anthropic/types/usage.py
+++ b/src/anthropic/types/usage.py
@@ -29,5 +29,8 @@ class Usage(BaseModel):
     server_tool_use: Optional[ServerToolUsage] = None
     """The number of server tool requests."""
 
+    thinking_tokens: Optional[int] = None
+    """The number of tokens used for thinking."""
+
     service_tier: Optional[Literal["standard", "priority", "batch"]] = None
     """If the request used the priority, standard, or batch tier."""
diff --git a/tests/lib/test_bedrock.py b/tests/lib/test_bedrock.py
index fe62da43..dee7d5c7 100644
--- a/tests/lib/test_bedrock.py
+++ b/tests/lib/test_bedrock.py
@@ -1,4 +1,5 @@
 import re
+import os
 import typing as t
 import tempfile
 from typing import TypedDict, cast
@@ -53,12 +54,18 @@ def mock_aws_config(
     profiles: t.List[AwsConfigProfile],
     monkeypatch: t.Any,
 ) -> t.Iterable[None]:
-    with tempfile.NamedTemporaryFile(mode="w+", delete=True) as temp_file:
+    temp_file = tempfile.NamedTemporaryFile(mode="w+", delete=False)
+    try:
         for profile in profiles:
             temp_file.write(profile_to_ini(profile))
         temp_file.flush()
+        temp_file.close()
         monkeypatch.setenv("AWS_CONFIG_FILE", str(temp_file.name))
+        monkeypatch.setenv("AWS_SDK_LOAD_CONFIG", "1")
         yield
+    finally:
+        if os.path.exists(temp_file.name):
+            os.unlink(temp_file.name)
 
 
 @pytest.mark.filterwarnings("ignore::DeprecationWarning")
diff --git a/uv.lock b/uv.lock
index f2064b8c..14f72de9 100644
--- a/uv.lock
+++ b/uv.lock
@@ -185,7 +185,7 @@ wheels = [
 
 [[package]]
 name = "anthropic"
-version = "0.75.0"
+version = "0.76.0"
 source = { editable = "." }
 dependencies = [
     { name = "anyio" },