fix: add e2e tests for anthropic thinking feature

Author: sebastienc

contributing/samples/hello_world_anthropic_thinking/__init__.py

@@ -0,0 +1,13 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.

contributing/samples/hello_world_anthropic_thinking/agent.py

@@ -0,0 +1,61 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from google.adk import Agent
+from google.adk.models.anthropic_llm import AnthropicLlm
+from google.adk.planners.built_in_planner import BuiltInPlanner
+from google.genai import types
+
+
+def check_prime(nums: list[int]) -> str:
+  """Check if a given list of numbers are prime.
+
+  Args:
+    nums: The list of numbers to check.
+
+  Returns:
+    A str indicating which numbers are prime.
+  """
+  primes = set()
+  for number in nums:
+    number = int(number)
+    if number <= 1:
+      continue
+    is_prime = True
+    for i in range(2, int(number**0.5) + 1):
+      if number % i == 0:
+        is_prime = False
+        break
+    if is_prime:
+      primes.add(number)
+  return (
+      "No prime numbers found."
+      if not primes
+      else f"{', '.join(str(num) for num in sorted(primes))} are prime numbers."
+  )
+
+
+root_agent = Agent(
+    model=AnthropicLlm(model="claude-sonnet-4-6"),
+    name="anthropic_thinking_agent",
+    description="An agent that uses Claude extended thinking via Vertex AI.",
+    instruction="""
+      You are a helpful assistant. Use your reasoning carefully before answering.
+      When asked to check prime numbers, use the check_prime tool.
+    """,
+    tools=[check_prime],
+    planner=BuiltInPlanner(
+        thinking_config=types.ThinkingConfig(thinking_budget=5000),
+    ),
+)