Add token usage to gemini (streaming), litellm and anthropic

Also included a token_usage sample that showcases the token usage of subagents with different models under a parent agent.

PiperOrigin-RevId: 759347015

contributing/samples/token_usage/agent.py

@@ -0,0 +1,97 @@
+# Copyright 2025 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.
+
+import random
+
+from google.adk import Agent
+from google.adk.agents.llm_agent import LlmAgent
+from google.adk.agents.sequential_agent import SequentialAgent
+from google.adk.models.anthropic_llm import Claude
+from google.adk.models.lite_llm import LiteLlm
+from google.adk.planners import BuiltInPlanner
+from google.adk.planners import PlanReActPlanner
+from google.adk.tools.tool_context import ToolContext
+from google.genai import types
+
+
+def roll_die(sides: int, tool_context: ToolContext) -> int:
+  """Roll a die and return the rolled result.
+
+  Args:
+    sides: The integer number of sides the die has.
+
+  Returns:
+    An integer of the result of rolling the die.
+  """
+  result = random.randint(1, sides)
+  if 'rolls' not in tool_context.state:
+    tool_context.state['rolls'] = []
+
+  tool_context.state['rolls'] = tool_context.state['rolls'] + [result]
+  return result
+
+
+roll_agent_with_openai = LlmAgent(
+    model=LiteLlm(model='openai/gpt-4o'),
+    description='Handles rolling dice of different sizes.',
+    name='roll_agent_with_openai',
+    instruction="""
+      You are responsible for rolling dice based on the user's request.
+      When asked to roll a die, you must call the roll_die tool with the number of sides as an integer.
+    """,
+    tools=[roll_die],
+)
+
+roll_agent_with_claude = LlmAgent(
+    model=Claude(model='claude-3-7-sonnet@20250219'),
+    description='Handles rolling dice of different sizes.',
+    name='roll_agent_with_claude',
+    instruction="""
+      You are responsible for rolling dice based on the user's request.
+      When asked to roll a die, you must call the roll_die tool with the number of sides as an integer.
+    """,
+    tools=[roll_die],
+)
+
+roll_agent_with_litellm_claude = LlmAgent(
+    model=LiteLlm(model='vertex_ai/claude-3-7-sonnet'),
+    description='Handles rolling dice of different sizes.',
+    name='roll_agent_with_litellm_claude',
+    instruction="""
+      You are responsible for rolling dice based on the user's request.
+      When asked to roll a die, you must call the roll_die tool with the number of sides as an integer.
+    """,
+    tools=[roll_die],
+)
+
+roll_agent_with_gemini = LlmAgent(
+    model='gemini-2.0-flash',
+    description='Handles rolling dice of different sizes.',
+    name='roll_agent_with_gemini',
+    instruction="""
+      You are responsible for rolling dice based on the user's request.
+      When asked to roll a die, you must call the roll_die tool with the number of sides as an integer.
+    """,
+    tools=[roll_die],
+)
+
+root_agent = SequentialAgent(
+    name='code_pipeline_agent',
+    sub_agents=[
+        roll_agent_with_openai,
+        roll_agent_with_claude,
+        roll_agent_with_litellm_claude,
+        roll_agent_with_gemini,
+    ],
+)