chore: import upstream snapshot with attribution

contributing/samples/hitl/human_in_loop/README.md

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+# Agent with Long-Running Tools
+
+This example demonstrates an agent using a long-running tool (`ask_for_approval`).
+
+## Key Flow for Long-Running Tools
+
+1. **Initial Call**: The agent calls the long-running tool (e.g., `ask_for_approval`).
+
+1. **Initial Tool Response**: The tool immediately returns an initial response, typically indicating a "pending" status and a way to track the request (e.g., a `ticket-id`). This is sent back to the agent as a `types.FunctionResponse` (usually processed internally by the runner and then influencing the agent's next turn).
+
+1. **Agent Acknowledges**: The agent processes this initial response and usually informs the user about the pending status.
+
+1. **External Process/Update**: The long-running task progresses externally (e.g., a human approves the request).
+
+1. **❗️Crucial Step: Provide Updated Tool Response❗️**:
+
+   - Once the external process completes or updates, your application **must** construct a new `types.FunctionResponse`.
+   - This response should use the **same `id` and `name`** as the original `FunctionCall` to the long-running tool.
+   - The `response` field within this `types.FunctionResponse` should contain the *updated data* (e.g., `{'status': 'approved', ...}`).
+   - Send this `types.FunctionResponse` back to the agent as a part within a new message using `role="user"`.
+
+   ```python
+   # Example: After external approval
+   updated_tool_output_data = {
+       "status": "approved",
+       "ticketId": ticket_id, # from original call
+       # ... other relevant updated data
+   }
+
+   updated_function_response_part = types.Part(
+       function_response=types.FunctionResponse(
+           id=long_running_function_call.id,   # Original call ID
+           name=long_running_function_call.name, # Original call name
+           response=updated_tool_output_data,
+       )
+   )
+
+   # Send this back to the agent
+   async for _ in runner.run_async(
+       # ... session_id, user_id ...
+       new_message=types.Content(
+           parts=[updated_function_response_part], role="user"
+       ),
+   ):
+       pass  # exhaust generator (or handle events)
+   ```
+
+1. **Agent Acts on Update**: The agent receives this message containing the `types.FunctionResponse` and, based on its instructions, proceeds with the next steps (e.g., calling another tool like `reimburse`).
+
+**Why is this important?** The agent relies on receiving this subsequent `types.FunctionResponse` (provided in a message with `role="user"` containing the specific `Part`) to understand that the long-running task has concluded or its state has changed. Without it, the agent will remain unaware of the outcome of the pending task.

contributing/samples/hitl/human_in_loop/__init__.py

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+# 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 . import agent

contributing/samples/hitl/human_in_loop/agent.py

@@ -0,0 +1,55 @@
+# 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 typing import Any
+
+from google.adk import Agent
+from google.adk.tools.long_running_tool import LongRunningFunctionTool
+from google.adk.tools.tool_context import ToolContext
+from google.genai import types
+
+
+def reimburse(purpose: str, amount: float) -> str:
+  """Reimburse the amount of money to the employee."""
+  return {
+      'status': 'ok',
+  }
+
+
+def ask_for_approval(
+    purpose: str, amount: float, tool_context: ToolContext
+) -> dict[str, Any]:
+  """Ask for approval for the reimbursement."""
+  return {
+      'status': 'pending',
+      'amount': amount,
+      'ticketId': 'reimbursement-ticket-001',
+  }
+
+
+root_agent = Agent(
+    name='reimbursement_agent',
+    instruction="""
+      You are an agent whose job is to handle the reimbursement process for
+      the employees. If the amount is less than $100, you will automatically
+      approve the reimbursement.
+
+      If the amount is greater than $100, you will
+      ask for approval from the manager. If the manager approves, you will
+      call reimburse() to reimburse the amount to the employee. If the manager
+      rejects, you will inform the employee of the rejection.
+""",
+    tools=[reimburse, LongRunningFunctionTool(func=ask_for_approval)],
+    generate_content_config=types.GenerateContentConfig(temperature=0.1),
+)

contributing/samples/hitl/human_in_loop/main.py

@@ -0,0 +1,192 @@
+# 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.
+
+import asyncio
+import os
+from typing import Any
+from typing import Union
+
+import agent
+from dotenv import load_dotenv
+from google.adk.agents.llm_agent import Agent
+from google.adk.events.event import Event
+from google.adk.runners import Runner
+from google.adk.sessions.in_memory_session_service import InMemorySessionService
+from google.adk.tools.long_running_tool import LongRunningFunctionTool
+from google.genai import types
+from opentelemetry import trace
+from opentelemetry.exporter.cloud_trace import CloudTraceSpanExporter
+from opentelemetry.sdk.trace import export
+from opentelemetry.sdk.trace import TracerProvider
+
+load_dotenv(override=True)
+
+APP_NAME = "human_in_the_loop"
+USER_ID = "1234"
+SESSION_ID = "session1234"
+
+session_service = InMemorySessionService()
+
+
+async def main():
+  session = await session_service.create_session(
+      app_name=APP_NAME, user_id=USER_ID, session_id=SESSION_ID
+  )
+  runner = Runner(
+      agent=agent.root_agent,
+      app_name=APP_NAME,
+      session_service=session_service,
+  )
+
+  async def call_agent(query: str):
+    content = types.Content(role="user", parts=[types.Part(text=query)])
+
+    print(f'>>> User Query: "{query}"')
+    print("--- Running agent's initial turn ---")
+
+    events_async = runner.run_async(
+        session_id=session.id, user_id=USER_ID, new_message=content
+    )
+
+    long_running_function_call: Union[types.FunctionCall, None] = None
+    initial_tool_response: Union[types.FunctionResponse, None] = None
+    ticket_id: Union[str, None] = None
+
+    async for event in events_async:
+      if event.content and event.content.parts:
+        for i, part in enumerate(event.content.parts):
+          if part.text:
+            print(f"    Part {i} [Text]: {part.text.strip()}")
+          if part.function_call:
+            print(
+                f"    Part {i} [FunctionCall]:"
+                f" {part.function_call.name}({part.function_call.args}) ID:"
+                f" {part.function_call.id}"
+            )
+            if not long_running_function_call and part.function_call.id in (
+                event.long_running_tool_ids or []
+            ):
+              long_running_function_call = part.function_call
+              print(
+                  "      (Captured as long_running_function_call for"
+                  f" '{part.function_call.name}')"
+              )
+          if part.function_response:
+            print(
+                f"    Part {i} [FunctionResponse]: For"
+                f" '{part.function_response.name}', ID:"
+                f" {part.function_response.id}, Response:"
+                f" {part.function_response.response}"
+            )
+            if (
+                long_running_function_call
+                and part.function_response.id == long_running_function_call.id
+            ):
+              initial_tool_response = part.function_response
+              if initial_tool_response.response:
+                ticket_id = initial_tool_response.response.get("ticketId")
+              print(
+                  "      (Captured as initial_tool_response for"
+                  f" '{part.function_response.name}', Ticket ID: {ticket_id})"
+              )
+
+    print("--- End of agent's initial turn ---\n")
+
+    if (
+        long_running_function_call
+        and initial_tool_response
+        and initial_tool_response.response.get("status") == "pending"
+    ):
+      print(f"--- Simulating external approval for ticket: {ticket_id} ---\n")
+
+      updated_tool_output_data = {
+          "status": "approved",
+          "ticketId": ticket_id,
+          "approver_feedback": (
+              "Approved by manager at " + str(asyncio.get_event_loop().time())
+          ),
+      }
+
+      updated_function_response_part = types.Part(
+          function_response=types.FunctionResponse(
+              id=long_running_function_call.id,
+              name=long_running_function_call.name,
+              response=updated_tool_output_data,
+          )
+      )
+
+      print(
+          "--- Sending updated tool result to agent for call ID"
+          f" {long_running_function_call.id}: {updated_tool_output_data} ---"
+      )
+      print("--- Running agent's turn AFTER receiving updated tool result ---")
+
+      async for event in runner.run_async(
+          session_id=session.id,
+          user_id=USER_ID,
+          new_message=types.Content(
+              parts=[updated_function_response_part], role="user"
+          ),
+      ):
+        if event.content and event.content.parts:
+          for i, part in enumerate(event.content.parts):
+            if part.text:
+              print(f"    Part {i} [Text]: {part.text.strip()}")
+            if part.function_call:
+              print(
+                  f"    Part {i} [FunctionCall]:"
+                  f" {part.function_call.name}({part.function_call.args}) ID:"
+                  f" {part.function_call.id}"
+              )
+            if part.function_response:
+              print(
+                  f"    Part {i} [FunctionResponse]: For"
+                  f" '{part.function_response.name}', ID:"
+                  f" {part.function_response.id}, Response:"
+                  f" {part.function_response.response}"
+              )
+      print("--- End of agent's turn AFTER receiving updated tool result ---")
+
+    elif long_running_function_call and not initial_tool_response:
+      print(
+          f"--- Long running function '{long_running_function_call.name}' was"
+          " called, but its initial response was not captured. ---"
+      )
+    elif not long_running_function_call:
+      print(
+          "--- No long running function call was detected in the initial"
+          " turn. ---"
+      )
+
+  await call_agent("Please reimburse $50 for meals")
+  print("=" * 70)
+  await call_agent("Please reimburse $200 for conference travel")
+
+
+if __name__ == "__main__":
+  provider = TracerProvider()
+  project_id = os.environ.get("GOOGLE_CLOUD_PROJECT")
+  if not project_id:
+    raise ValueError("GOOGLE_CLOUD_PROJECT environment variable is not set.")
+  print("Tracing to project", project_id)
+  processor = export.BatchSpanProcessor(
+      CloudTraceSpanExporter(project_id=project_id)
+  )
+  provider.add_span_processor(processor)
+  trace.set_tracer_provider(provider)
+
+  asyncio.run(main())
+
+  provider.force_flush()
+  print("Done tracing to project", project_id)

contributing/samples/hitl/human_in_loop/tests/auto_reimburse_coffee.json

@@ -0,0 +1,84 @@
+{
+  "events": [
+    {
+      "author": "user",
+      "content": {
+        "parts": [
+          {
+            "text": "Can I get a reimbursement of $15.50 for some coffee?"
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-1",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": ""
+      }
+    },
+    {
+      "author": "reimbursement_agent",
+      "content": {
+        "parts": [
+          {
+            "functionCall": {
+              "args": {
+                "amount": 15.5,
+                "purpose": "coffee"
+              },
+              "id": "fc-1",
+              "name": "reimburse"
+            }
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "id": "e-2",
+      "invocationId": "i-1",
+      "longRunningToolIds": [],
+      "nodeInfo": {
+        "path": "reimbursement_agent@1"
+      }
+    },
+    {
+      "author": "reimbursement_agent",
+      "content": {
+        "parts": [
+          {
+            "functionResponse": {
+              "id": "fc-1",
+              "name": "reimburse",
+              "response": {
+                "status": "ok"
+              }
+            }
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-3",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "reimbursement_agent@1"
+      }
+    },
+    {
+      "author": "reimbursement_agent",
+      "content": {
+        "parts": [
+          {
+            "text": "You got it! I've reimbursed you $15.50 for coffee."
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "id": "e-4",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "reimbursement_agent@1"
+      }
+    }
+  ]
+}

contributing/samples/hitl/human_in_loop/tests/reimburse_dinner.json

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+{
+  "events": [
+    {
+      "author": "user",
+      "content": {
+        "parts": [
+          {
+            "text": "I would like to request a reimbursement of $150 for a client dinner."
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-1",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": ""
+      }
+    },
+    {
+      "author": "reimbursement_agent",
+      "content": {
+        "parts": [
+          {
+            "functionCall": {
+              "args": {
+                "amount": 150,
+                "purpose": "client dinner"
+              },
+              "id": "fc-1",
+              "name": "ask_for_approval"
+            }
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "id": "e-2",
+      "invocationId": "i-1",
+      "longRunningToolIds": [
+        "fc-1"
+      ],
+      "nodeInfo": {
+        "path": "reimbursement_agent@1"
+      }
+    },
+    {
+      "author": "reimbursement_agent",
+      "content": {
+        "parts": [
+          {
+            "functionResponse": {
+              "id": "fc-1",
+              "name": "ask_for_approval",
+              "response": {
+                "amount": 150,
+                "status": "pending",
+                "ticketId": "reimbursement-ticket-001"
+              }
+            }
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-3",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "reimbursement_agent@1"
+      }
+    },
+    {
+      "author": "reimbursement_agent",
+      "content": {
+        "parts": [
+          {
+            "text": "Your reimbursement request for $150 for a client dinner has been sent for approval. Your ticket ID is reimbursement-ticket-001. I will let you know once I have an update."
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "id": "e-4",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "reimbursement_agent@1"
+      }
+    }
+  ]
+}

contributing/samples/hitl/human_tool_confirmation/__init__.py

@@ -0,0 +1,15 @@
+# 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 . import agent

contributing/samples/hitl/human_tool_confirmation/agent.py

@@ -0,0 +1,100 @@
+# 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.apps import App
+from google.adk.apps import ResumabilityConfig
+from google.adk.tools.function_tool import FunctionTool
+from google.adk.tools.tool_confirmation import ToolConfirmation
+from google.adk.tools.tool_context import ToolContext
+from google.genai import types
+
+
+def reimburse(amount: int, tool_context: ToolContext) -> str:
+  """Reimburse the employee for the given amount."""
+  return {'status': 'ok'}
+
+
+async def confirmation_threshold(
+    amount: int, tool_context: ToolContext
+) -> bool:
+  """Returns true if the amount is greater than 1000."""
+  return amount > 1000
+
+
+def request_time_off(days: int, tool_context: ToolContext):
+  """Request day off for the employee."""
+  if days <= 0:
+    return {'status': 'Invalid days to request.'}
+
+  if days <= 2:
+    return {
+        'status': 'ok',
+        'approved_days': days,
+    }
+
+  tool_confirmation = tool_context.tool_confirmation
+  if not tool_confirmation:
+    tool_context.request_confirmation(
+        hint=(
+            'Please approve or reject the tool call request_time_off() by'
+            ' responding with a FunctionResponse with an expected'
+            ' ToolConfirmation payload.'
+        ),
+        payload={
+            'approved_days': 0,
+        },
+    )
+    return {'status': 'Manager approval is required.'}
+
+  approved_days = tool_confirmation.payload['approved_days']
+  approved_days = min(approved_days, days)
+  if approved_days == 0:
+    return {'status': 'The time off request is rejected.', 'approved_days': 0}
+  return {
+      'status': 'ok',
+      'approved_days': approved_days,
+  }
+
+
+root_agent = Agent(
+    name='time_off_agent',
+    instruction="""
+    You are a helpful assistant that can help employees with reimbursement and time off requests.
+    - Use the `reimburse` tool for reimbursement requests.
+    - Use the `request_time_off` tool for time off requests.
+    - Prioritize using tools to fulfill the user's request.
+    - Always respond to the user with the tool results.
+    """,
+    tools=[
+        # Set require_confirmation to True or a callable to require user
+        # confirmation for the tool call. This is an easier way to get user
+        # confirmation if the tool just need a boolean confirmation.
+        FunctionTool(
+            reimburse,
+            require_confirmation=confirmation_threshold,
+        ),
+        request_time_off,
+    ],
+    generate_content_config=types.GenerateContentConfig(temperature=0.1),
+)
+
+app = App(
+    name='human_tool_confirmation',
+    root_agent=root_agent,
+    # Set the resumability config to enable resumability.
+    resumability_config=ResumabilityConfig(
+        is_resumable=True,
+    ),
+)

contributing/samples/hitl/request_input_tool/README.md

@@ -0,0 +1,49 @@
+# Request Input Tool Sample
+
+## Overview
+
+This sample demonstrates how an LLM agent can proactively request clarification or confirmation from the user using the built-in `request_input` tool without losing its context/flow.
+
+It showcases a highly realistic support assistant that dynamically constructs a JSON schema to only ask for missing details when creating IT support tickets.
+
+## Sample Inputs
+
+- `I want to file a technical ticket for a database crash.`
+
+  The agent will analyze the prompt, identify that the `title` and `category` are already provided, and dynamically call `request_input` with a schema requesting only `description` and `priority`.
+
+- `File a priority HIGH technical ticket titled database crash explained as the MySQL server throwing OOM errors.`
+
+  The agent has all required details and will call `create_support_ticket` immediately without needing clarification.
+
+## Graph
+
+```mermaid
+graph TD
+    User[User Prompt] --> Agent[Support Assistant Agent]
+    Agent -->|Needs Clarification| RequestInput[request_input tool]
+    RequestInput -->|User Response| Agent
+    Agent -->|All Details Gathered| CreateTicket[create_support_ticket tool]
+```
+
+## How To
+
+This sample uses **Pattern B: Standalone Agents** with the `request_input` tool:
+
+1. **Import `request_input`**:
+
+   ```python
+   from google.adk.tools import request_input
+   ```
+
+1. **Add it to the LLM Agent's tools list**:
+
+   ```python
+   root_agent = Agent(
+       name="support_assistant_agent",
+       tools=[create_support_ticket, request_input],
+       ...
+   )
+   ```
+
+When the LLM decides it needs clarification, it calls `request_input` with a question and a dynamic `response_schema`. The ADK framework automatically intercepts this, yields a long-running interrupt to the client, and injects the user's reply back as a `FunctionResponse` into the LLM's chat history.

contributing/samples/hitl/request_input_tool/agent.py

@@ -0,0 +1,62 @@
+# 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.tools import request_input
+from google.genai import types
+from pydantic import BaseModel
+from pydantic import Field
+
+
+class SupportTicket(BaseModel):
+  """Details of the IT support ticket to be created."""
+
+  title: str = Field(description="A brief summary of the issue.")
+  description: str = Field(description="Detailed explanation of the problem.")
+  priority: str = Field(
+      default="MEDIUM",
+      description="Ticket priority: LOW, MEDIUM, HIGH, or CRITICAL.",
+  )
+  category: str = Field(
+      description=(
+          "Issue category, e.g., billing, technical, account, or database."
+      )
+  )
+
+
+def create_support_ticket(ticket: SupportTicket) -> dict[str, str]:
+  """Create a support ticket in the IT ticketing system."""
+  return {
+      "status": "success",
+      "message": (
+          f"Successfully created ticket '{ticket.title}'"
+          f" [Category: {ticket.category}, Priority: {ticket.priority}]."
+      ),
+      "ticket_id": "INC-98471",
+  }
+
+
+root_agent = Agent(
+    name="support_assistant_agent",
+    instruction="""
+      You are a helpful IT support assistant responsible for creating support tickets.
+      When the user requests to create or file a ticket:
+      1. Identify which ticket details (title, description, priority, category) are already provided in the conversation.
+      2. If any mandatory details are missing, call the `request_input` tool.
+      3. When calling `request_input`, you must construct a dynamic JSON `response_schema` (type: "object") that ONLY requests the missing details, and specify a helpful message explaining what is needed.
+      4. Once all details are gathered, call `create_support_ticket` with the complete SupportTicket details.
+    """,
+    tools=[create_support_ticket, request_input],
+    generate_content_config=types.GenerateContentConfig(temperature=0.1),
+)

contributing/samples/hitl/request_input_tool/tests/create_support_ticket.json

@@ -0,0 +1,159 @@
+{
+  "events": [
+    {
+      "author": "user",
+      "content": {
+        "parts": [
+          {
+            "text": "I want to file a technical ticket for a database crash."
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-1",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": ""
+      }
+    },
+    {
+      "author": "support_assistant_agent",
+      "content": {
+        "parts": [
+          {
+            "functionCall": {
+              "args": {
+                "message": "I can help with that. Please provide the description and priority of the database crash:",
+                "response_schema": {
+                  "properties": {
+                    "description": {
+                      "description": "Detailed explanation of the database crash problem.",
+                      "title": "Description",
+                      "type": "string"
+                    },
+                    "priority": {
+                      "description": "Ticket priority: LOW, MEDIUM, HIGH, or CRITICAL.",
+                      "title": "Priority",
+                      "type": "string"
+                    }
+                  },
+                  "required": [
+                    "description",
+                    "priority"
+                  ],
+                  "title": "TicketClarification",
+                  "type": "object"
+                }
+              },
+              "id": "fc-1",
+              "name": "adk_request_input"
+            }
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "id": "e-2",
+      "invocationId": "i-1",
+      "longRunningToolIds": [
+        "fc-1"
+      ],
+      "nodeInfo": {
+        "path": "support_assistant_agent@1"
+      }
+    },
+    {
+      "author": "user",
+      "content": {
+        "parts": [
+          {
+            "functionResponse": {
+              "id": "fc-1",
+              "name": "adk_request_input",
+              "response": {
+                "description": "The MySQL server is throwing OOM errors and restarting repeatedly.",
+                "priority": "HIGH"
+              }
+            }
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-3",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": ""
+      }
+    },
+    {
+      "author": "support_assistant_agent",
+      "content": {
+        "parts": [
+          {
+            "functionCall": {
+              "args": {
+                "ticket": {
+                  "category": "database",
+                  "description": "The MySQL server is throwing OOM errors and restarting repeatedly.",
+                  "priority": "HIGH",
+                  "title": "Database crash"
+                }
+              },
+              "id": "fc-2",
+              "name": "create_support_ticket"
+            }
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "id": "e-4",
+      "invocationId": "i-1",
+      "longRunningToolIds": [],
+      "nodeInfo": {
+        "path": "support_assistant_agent@1"
+      }
+    },
+    {
+      "author": "support_assistant_agent",
+      "content": {
+        "parts": [
+          {
+            "functionResponse": {
+              "id": "fc-2",
+              "name": "create_support_ticket",
+              "response": {
+                "message": "Successfully created ticket 'Database crash' [Category: database, Priority: HIGH].",
+                "status": "success",
+                "ticket_id": "INC-98471"
+              }
+            }
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-5",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "support_assistant_agent@1"
+      }
+    },
+    {
+      "author": "support_assistant_agent",
+      "content": {
+        "parts": [
+          {
+            "text": "Successfully created ticket 'Database crash' [Category: database, Priority: HIGH] with ticket ID INC-98471."
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "id": "e-6",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "support_assistant_agent@1"
+      }
+    }
+  ]
+}

contributing/samples/hitl/tool_confirmation/README.md

@@ -0,0 +1,64 @@
+# Tool Confirmation Sample
+
+## Overview
+
+This sample demonstrates how to use the Tool Confirmation feature in ADK to implement Human-in-the-Loop (HITL) flows. It shows how a tool can dynamically request confirmation from the user before proceeding with a sensitive action (e.g., transferring funds).
+
+## Sample Inputs
+
+- `Transfer $50 to Alice`
+
+- `Transfer $200 to Bob`
+
+- `Close account ACC123`
+
+- `Transfer $500 to Charlie and close account ACC123`
+
+  *This will cause parallel tools being called in a single step*
+
+## How To
+
+### 1. Requesting Confirmation
+
+In your tool function, you can access the `ToolContext` and check if `tool_confirmation` is present. If not, you can call `tool_context.request_confirmation()` to request approval from the user.
+
+```python
+def transfer_funds(amount: float, recipient: str, tool_context: ToolContext):
+    # Only request confirmation for amounts >= 100
+    if amount >= 100:
+        if not tool_context.tool_confirmation:
+            tool_context.request_confirmation(
+                hint=f"Confirm transfer of ${amount} to {recipient}.",
+            )
+            return {"error": "This tool call requires confirmation, please approve or reject."}
+```
+
+### 2. Handling the Response
+
+When the user responds to the confirmation request, the tool will be called again. This time, `tool_context.tool_confirmation` will be populated with the user's decision (`confirmed` boolean).
+
+```python
+        elif not tool_context.tool_confirmation.confirmed:
+            return {"error": "Transfer rejected by user."}
+
+    return {"result": f"Successfully transferred ${amount} to {recipient}."}
+```
+
+### 3. Using `FunctionTool` for Automatic Confirmation
+
+Alternatively, you can specify that a tool always requires confirmation by wrapping it in a `FunctionTool` and setting `require_confirmation=True` when defining the agent's tools. In this case, the runner will automatically handle the confirmation request before calling your function.
+
+```python
+from google.adk.tools.function_tool import FunctionTool
+
+def close_account(account_id: str, tool_context: ToolContext):
+    # This code only runs if the user approves the confirmation
+    return {"result": f"Account {account_id} closed."}
+
+root_agent = Agent(
+    ...
+    tools=[
+        FunctionTool(func=close_account, require_confirmation=True),
+    ],
+)
+```

contributing/samples/hitl/tool_confirmation/__init__.py

@@ -0,0 +1,15 @@
+# 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 . import agent

contributing/samples/hitl/tool_confirmation/agent.py

@@ -0,0 +1,57 @@
+# 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 __future__ import annotations
+
+from google.adk.agents import Agent
+from google.adk.tools.function_tool import FunctionTool
+from google.adk.tools.tool_context import ToolContext
+
+
+def transfer_funds(
+    amount: float, recipient: str, tool_context: ToolContext
+) -> dict[str, str]:
+  """Transfers funds to a recipient."""
+  # Only request confirmation for amounts >= 100
+  if amount >= 100:
+    if not tool_context.tool_confirmation:
+      tool_context.request_confirmation(
+          hint=f"Confirm transfer of ${amount} to {recipient}.",
+      )
+      return {
+          "error": (
+              "This tool call requires confirmation, please approve or reject."
+          )
+      }
+    elif not tool_context.tool_confirmation.confirmed:
+      return {"error": "Transfer rejected by user."}
+
+  # Proceed with transfer for amounts < 100 or if confirmed
+  return {"result": f"Successfully transferred ${amount} to {recipient}."}
+
+
+def close_account(account_id: str) -> dict[str, str]:
+  """Closes a user account. This is a destructive action."""
+  # With require_confirmation=True, this function is only called if the user
+  # approves.
+  return {"result": f"Account {account_id} closed successfully."}
+
+
+root_agent = Agent(
+    name="money_transfer_assistant",
+    tools=[
+        transfer_funds,
+        FunctionTool(func=close_account, require_confirmation=True),
+    ],
+)

contributing/samples/hitl/tool_confirmation/tests/Transfer_500_and_close_account_ACC123.json

@@ -0,0 +1,276 @@
+{
+  "events": [
+    {
+      "author": "user",
+      "content": {
+        "parts": [
+          {
+            "text": "Transfer $500 to Charlie and close account ACC123"
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-1",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": ""
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "functionCall": {
+              "args": {
+                "amount": 500,
+                "recipient": "Charlie"
+              },
+              "id": "fc-1",
+              "name": "transfer_funds"
+            }
+          },
+          {
+            "functionCall": {
+              "args": {
+                "account_id": "ACC123"
+              },
+              "id": "fc-2",
+              "name": "close_account"
+            }
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "id": "e-2",
+      "invocationId": "i-1",
+      "longRunningToolIds": [],
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "functionCall": {
+              "args": {
+                "originalFunctionCall": {
+                  "args": {
+                    "amount": 500,
+                    "recipient": "Charlie"
+                  },
+                  "id": "fc-1",
+                  "name": "transfer_funds"
+                },
+                "toolConfirmation": {
+                  "confirmed": false,
+                  "hint": "Confirm transfer of $500 to Charlie."
+                }
+              },
+              "id": "fc-3",
+              "name": "adk_request_confirmation"
+            }
+          },
+          {
+            "functionCall": {
+              "args": {
+                "originalFunctionCall": {
+                  "args": {
+                    "account_id": "ACC123"
+                  },
+                  "id": "fc-2",
+                  "name": "close_account"
+                },
+                "toolConfirmation": {
+                  "confirmed": false,
+                  "hint": "Please approve or reject the tool call close_account() by responding with a FunctionResponse with an expected ToolConfirmation payload."
+                }
+              },
+              "id": "fc-4",
+              "name": "adk_request_confirmation"
+            }
+          }
+        ],
+        "role": "model"
+      },
+      "id": "e-3",
+      "invocationId": "i-1",
+      "longRunningToolIds": [
+        "fc-4",
+        "fc-3"
+      ],
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "actions": {
+        "requestedToolConfirmations": {
+          "fc-1": {
+            "confirmed": false,
+            "hint": "Confirm transfer of $500 to Charlie."
+          },
+          "fc-2": {
+            "confirmed": false,
+            "hint": "Please approve or reject the tool call close_account() by responding with a FunctionResponse with an expected ToolConfirmation payload."
+          }
+        },
+        "skipSummarization": true
+      },
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "functionResponse": {
+              "id": "fc-1",
+              "name": "transfer_funds",
+              "response": {
+                "error": "This tool call requires confirmation, please approve or reject."
+              }
+            }
+          },
+          {
+            "functionResponse": {
+              "id": "fc-2",
+              "name": "close_account",
+              "response": {
+                "error": "This tool call requires confirmation, please approve or reject."
+              }
+            }
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-4",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "author": "user",
+      "content": {
+        "parts": [
+          {
+            "functionResponse": {
+              "id": "fc-3",
+              "name": "adk_request_confirmation",
+              "response": {
+                "confirmed": true
+              }
+            }
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-5",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": ""
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "functionResponse": {
+              "id": "fc-1",
+              "name": "transfer_funds",
+              "response": {
+                "result": "Successfully transferred $500 to Charlie."
+              }
+            }
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-6",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "text": "I transferred $500 to Charlie. I can close account ACC123, but it is a destructive action that requires confirmation. Do you want me to go ahead and close it?"
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "id": "e-7",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "author": "user",
+      "content": {
+        "parts": [
+          {
+            "functionResponse": {
+              "id": "fc-4",
+              "name": "adk_request_confirmation",
+              "response": {
+                "confirmed": true
+              }
+            }
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-8",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": ""
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "functionResponse": {
+              "id": "fc-2",
+              "name": "close_account",
+              "response": {
+                "result": "Account ACC123 closed successfully."
+              }
+            }
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-9",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "text": "I have transferred $500 to Charlie and closed account ACC123.\n"
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "id": "e-10",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    }
+  ]
+}

contributing/samples/hitl/tool_confirmation/tests/close_account_acc123.json

@@ -0,0 +1,171 @@
+{
+  "events": [
+    {
+      "author": "user",
+      "content": {
+        "parts": [
+          {
+            "text": "Close account ACC123\n"
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-1",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": ""
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "functionCall": {
+              "args": {
+                "account_id": "ACC123"
+              },
+              "id": "fc-1",
+              "name": "close_account"
+            }
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "id": "e-2",
+      "invocationId": "i-1",
+      "longRunningToolIds": [],
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "functionCall": {
+              "args": {
+                "originalFunctionCall": {
+                  "args": {
+                    "account_id": "ACC123"
+                  },
+                  "id": "fc-1",
+                  "name": "close_account"
+                },
+                "toolConfirmation": {
+                  "confirmed": false,
+                  "hint": "Please approve or reject the tool call close_account() by responding with a FunctionResponse with an expected ToolConfirmation payload."
+                }
+              },
+              "id": "fc-2",
+              "name": "adk_request_confirmation"
+            }
+          }
+        ],
+        "role": "model"
+      },
+      "id": "e-3",
+      "invocationId": "i-1",
+      "longRunningToolIds": [
+        "fc-2"
+      ],
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "actions": {
+        "requestedToolConfirmations": {
+          "fc-1": {
+            "confirmed": false,
+            "hint": "Please approve or reject the tool call close_account() by responding with a FunctionResponse with an expected ToolConfirmation payload."
+          }
+        },
+        "skipSummarization": true
+      },
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "functionResponse": {
+              "id": "fc-1",
+              "name": "close_account",
+              "response": {
+                "error": "This tool call requires confirmation, please approve or reject."
+              }
+            }
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-4",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "author": "user",
+      "content": {
+        "parts": [
+          {
+            "functionResponse": {
+              "id": "fc-2",
+              "name": "adk_request_confirmation",
+              "response": {
+                "confirmed": true
+              }
+            }
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-5",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": ""
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "functionResponse": {
+              "id": "fc-1",
+              "name": "close_account",
+              "response": {
+                "result": "Account ACC123 closed successfully."
+              }
+            }
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-6",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "text": "I have closed the account ACC123."
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "id": "e-7",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    }
+  ]
+}

contributing/samples/hitl/tool_confirmation/tests/transfer_200_confirmed.json

@@ -0,0 +1,189 @@
+{
+  "events": [
+    {
+      "author": "user",
+      "content": {
+        "parts": [
+          {
+            "text": "Transfer $200 to Bob"
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-1",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": ""
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "functionCall": {
+              "args": {
+                "amount": 200,
+                "recipient": "Bob"
+              },
+              "id": "fc-1",
+              "name": "transfer_funds"
+            }
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "id": "e-2",
+      "invocationId": "i-1",
+      "longRunningToolIds": [],
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "functionCall": {
+              "args": {
+                "originalFunctionCall": {
+                  "args": {
+                    "amount": 200,
+                    "recipient": "Bob"
+                  },
+                  "id": "fc-1",
+                  "name": "transfer_funds"
+                },
+                "toolConfirmation": {
+                  "confirmed": false,
+                  "hint": "Confirm transfer of $200 to Bob."
+                }
+              },
+              "id": "fc-2",
+              "name": "adk_request_confirmation"
+            }
+          }
+        ],
+        "role": "model"
+      },
+      "id": "e-3",
+      "invocationId": "i-1",
+      "longRunningToolIds": [
+        "fc-2"
+      ],
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "actions": {
+        "requestedToolConfirmations": {
+          "fc-1": {
+            "confirmed": false,
+            "hint": "Confirm transfer of $200 to Bob."
+          }
+        }
+      },
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "functionResponse": {
+              "id": "fc-1",
+              "name": "transfer_funds",
+              "response": {
+                "error": "This tool call requires confirmation, please approve or reject."
+              }
+            }
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-4",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "text": "I need to confirm this transfer with you. Please approve or reject."
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "id": "e-5",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "author": "user",
+      "content": {
+        "parts": [
+          {
+            "functionResponse": {
+              "id": "fc-2",
+              "name": "adk_request_confirmation",
+              "response": {
+                "confirmed": true
+              }
+            }
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-6",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": ""
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "functionResponse": {
+              "id": "fc-1",
+              "name": "transfer_funds",
+              "response": {
+                "result": "Successfully transferred $200 to Bob."
+              }
+            }
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-7",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "text": "Successfully transferred $200 to Bob."
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "id": "e-8",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    }
+  ]
+}

contributing/samples/hitl/tool_confirmation/tests/transfer_200_declined.json

@@ -0,0 +1,189 @@
+{
+  "events": [
+    {
+      "author": "user",
+      "content": {
+        "parts": [
+          {
+            "text": "Transfer $200 to Bob"
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-1",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": ""
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "functionCall": {
+              "args": {
+                "amount": 200,
+                "recipient": "Bob"
+              },
+              "id": "fc-1",
+              "name": "transfer_funds"
+            }
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "id": "e-2",
+      "invocationId": "i-1",
+      "longRunningToolIds": [],
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "functionCall": {
+              "args": {
+                "originalFunctionCall": {
+                  "args": {
+                    "amount": 200,
+                    "recipient": "Bob"
+                  },
+                  "id": "fc-1",
+                  "name": "transfer_funds"
+                },
+                "toolConfirmation": {
+                  "confirmed": false,
+                  "hint": "Confirm transfer of $200 to Bob."
+                }
+              },
+              "id": "fc-2",
+              "name": "adk_request_confirmation"
+            }
+          }
+        ],
+        "role": "model"
+      },
+      "id": "e-3",
+      "invocationId": "i-1",
+      "longRunningToolIds": [
+        "fc-2"
+      ],
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "actions": {
+        "requestedToolConfirmations": {
+          "fc-1": {
+            "confirmed": false,
+            "hint": "Confirm transfer of $200 to Bob."
+          }
+        }
+      },
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "functionResponse": {
+              "id": "fc-1",
+              "name": "transfer_funds",
+              "response": {
+                "error": "This tool call requires confirmation, please approve or reject."
+              }
+            }
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-4",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "text": "Your transfer of $200 to Bob requires confirmation."
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "id": "e-5",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "author": "user",
+      "content": {
+        "parts": [
+          {
+            "functionResponse": {
+              "id": "fc-2",
+              "name": "adk_request_confirmation",
+              "response": {
+                "confirmed": false
+              }
+            }
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-6",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": ""
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "functionResponse": {
+              "id": "fc-1",
+              "name": "transfer_funds",
+              "response": {
+                "error": "Transfer rejected by user."
+              }
+            }
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-7",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "text": "I'm sorry, your transfer could not be completed. It was rejected by the user."
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "id": "e-8",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    }
+  ]
+}

contributing/samples/hitl/tool_confirmation/tests/transfer_50.json

@@ -0,0 +1,84 @@
+{
+  "events": [
+    {
+      "author": "user",
+      "content": {
+        "parts": [
+          {
+            "text": "Transfer $50 to Alice\n"
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-1",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": ""
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "functionCall": {
+              "args": {
+                "amount": 50,
+                "recipient": "Alice"
+              },
+              "id": "fc-1",
+              "name": "transfer_funds"
+            }
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "id": "e-2",
+      "invocationId": "i-1",
+      "longRunningToolIds": [],
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "functionResponse": {
+              "id": "fc-1",
+              "name": "transfer_funds",
+              "response": {
+                "result": "Successfully transferred $50 to Alice."
+              }
+            }
+          }
+        ],
+        "role": "user"
+      },
+      "id": "e-3",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    },
+    {
+      "author": "money_transfer_assistant",
+      "content": {
+        "parts": [
+          {
+            "text": "Successfully transferred $50 to Alice."
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "id": "e-4",
+      "invocationId": "i-1",
+      "nodeInfo": {
+        "path": "money_transfer_assistant@1"
+      }
+    }
+  ]
+}

contributing/samples/hitl/tool_human_in_the_loop_config/README.md

@@ -0,0 +1,3 @@
+# Config-based Agent Sample - Human-In-The-Loop
+
+From contributing/samples/human_in_loop/

contributing/samples/hitl/tool_human_in_the_loop_config/__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/hitl/tool_human_in_the_loop_config/root_agent.yaml

@@ -0,0 +1,31 @@
+# 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.
+
+# yaml-language-server: $schema=https://raw.githubusercontent.com/google/adk-python/refs/heads/main/src/google/adk/agents/config_schemas/AgentConfig.json
+name: reimbursement_agent
+model: gemini-2.5-flash
+instruction: |
+  You are an agent whose job is to handle the reimbursement process for
+      the employees. If the amount is less than $100, you will automatically
+      approve the reimbursement.
+
+      If the amount is greater than $100, you will
+      ask for approval from the manager. If the manager approves, you will
+      call reimburse() to reimburse the amount to the employee. If the manager
+      rejects, you will inform the employee of the rejection.
+tools:
+  - name: tool_human_in_the_loop_config.tools.reimburse
+  - name: LongRunningFunctionTool
+    args:
+      func: tool_human_in_the_loop_config.tools.ask_for_approval

contributing/samples/hitl/tool_human_in_the_loop_config/tools.py

@@ -0,0 +1,35 @@
+# 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 typing import Any
+
+from google.adk.tools.tool_context import ToolContext
+
+
+def reimburse(purpose: str, amount: float) -> str:
+  """Reimburse the amount of money to the employee."""
+  return {
+      'status': 'ok',
+  }
+
+
+def ask_for_approval(
+    purpose: str, amount: float, tool_context: ToolContext
+) -> dict[str, Any]:
+  """Ask for approval for the reimbursement."""
+  return {
+      'status': 'pending',
+      'amount': amount,
+      'ticketId': 'reimbursement-ticket-001',
+  }