fix(tools): Add proper cleanup for AgentTool to prevent MCP session errors

Clean up runner resources in AgentTool after sub-agent execution to ensure
MCP sessions are closed in the correct async task context. Without this fix,
MCP sessions were cleaned up during garbage collection in a different task,
causing "Attempted to exit cancel scope in a different task" errors.

This fix ensures that `runner.close()` is called immediately after the
sub-agent finishes executing, properly closing all MCP sessions and other
resources within the same async task context they were created in.

Also adds two demo agents showing how to use AgentTool with MCP tools:
- mcp_in_agent_tool_remote: Uses SSE mode (remote server connection)
- mcp_in_agent_tool_stdio: Uses stdio mode (local subprocess)

Both demos use Gemini 2.5 Flash and include zero-installation setup using uvx.

Related: #1112, #929

.github/ISSUE_TEMPLATE/bug_report.md

@@ -19,7 +19,7 @@ Steps to reproduce the behavior:
 1. Install '...'
 2. Run '....'
 3. Open '....'
-4. Provide error or stacktrace
+4. Provie error or stacktrace
 
 **Expected behavior**
 A clear and concise description of what you expected to happen.

CHANGELOG.md

@@ -79,8 +79,6 @@
 * Fix issue with MCP tools throwing an error ([1a4261a](https://github.com/google/adk-python/commit/1a4261ad4b66cdeb39d39110a086bd6112b17516))
 * Remove redundant `format` field from LiteLLM content objects ([489c39d](https://github.com/google/adk-python/commit/489c39db01465e38ecbc2c7f32781c349b8cddc9))
 * Update the contribution analysis tool to use original write mode ([54db3d4](https://github.com/google/adk-python/commit/54db3d4434e0706b83a589fa2499d11d439a6e4e))
-* Fix agent evaluations detailed output rows wrapping issue([4284c61](https://github.com/google/adk-python/commit/4284c619010b8246c1ecaa011f14b6cc9de512dd))
-* Update dependency version constraints to be based on PyPI versions([0b1784e](https://github.com/google/adk-python/commit/0b1784e0e493a0e2df1edfe37e5ed5f4247e7d9d))
 
 ### Improvements
 
@@ -99,14 +97,13 @@
 * Add sample agent for VertexAiCodeExecutor ([edfe553](https://github.com/google/adk-python/commit/edfe5539421d196ca4da14d3a37fac7b598f8c8d))
 * Adds a new sample agent that demonstrates how to integrate PostgreSQL databases using the Model Context Protocol (MCP) ([45a2168](https://github.com/google/adk-python/commit/45a2168e0e6773e595ecfb825d7e4ab0a38c3a38))
 * Add example for using ADK with Fast MCP sampling ([d3796f9](https://github.com/google/adk-python/commit/d3796f9b33251d28d05e6701f11e80f02a2a49e1))
-* Refactor gepa sample code and clean-up user demo colab([63353b2](https://github.com/google/adk-python/commit/63353b2b74e23e97385892415c5a3f2a59c3504f))
 
 ## [1.17.0](https://github.com/google/adk-python/compare/v1.16.0...v1.17.0) (2025-10-22)
 
 ### Features
 
 * **[Core]**
-  * Add a service registry to provide a generic way to register custom service implementations to be used in FastAPI server. See [short instruction](https://github.com/google/adk-python/discussions/3175#discussioncomment-14745120). ([391628f](https://github.com/google/adk-python/commit/391628fcdc7b950c6835f64ae3ccab197163c990))
+  * Add a service registry to provide a generic way to register custom service implementations to be used in FastAPI server. See short instruction [here](https://github.com/google/adk-python/discussions/3175#discussioncomment-14745120). ([391628f](https://github.com/google/adk-python/commit/391628fcdc7b950c6835f64ae3ccab197163c990))
   * Add the ability to rewind a session to before a previous invocation ([9dce06f](https://github.com/google/adk-python/commit/9dce06f9b00259ec42241df4f6638955e783a9d1))
   * Support resuming a parallel agent with multiple branches paused on tool confirmation requests ([9939e0b](https://github.com/google/adk-python/commit/9939e0b087094038b90d86c2fd35c26dd63f1157))
   * Support content union as static instruction ([cc24d61](https://github.com/google/adk-python/commit/cc24d616f80c0eba2b09239b621cf3d176f144ea))
@@ -173,8 +170,9 @@
 * Set default for `bypass_multi_tools_limit` to False for GoogleSearchTool and VertexAiSearchTool ([6da7274](https://github.com/google/adk-python/commit/6da727485898137948d72906d86d78b6db6331ac))
 * Add more clear instruction to the doc updater agent about one PR for each recommended change ([b21d0a5](https://github.com/google/adk-python/commit/b21d0a50d610407be2f10b73a91274840ffdfe18))
 * Add a guideline to avoid content deletion ([16b030b](https://github.com/google/adk-python/commit/16b030b2b25a9b0b489e47b4b148fc4d39aeffcb))
-* Add a sample agent for the `ReflectAndRetryToolPlugin` ([9b8a4aa](https://github.com/google/adk-python/commit/9b8a4aad6fe65ef37885e5c3368d2799a2666534))
+* Add an sample agent for the `ReflectAndRetryToolPlugin` ([9b8a4aa](https://github.com/google/adk-python/commit/9b8a4aad6fe65ef37885e5c3368d2799a2666534))
 * Improve error message when adk web is run in wrong directory ([4a842c5](https://github.com/google/adk-python/commit/4a842c5a1334c3ee01406f796651299589fe12ab))
+* Add an sample agent for the `ReflectAndRetryToolPlugin` ([9b8a4aa](https://github.com/google/adk-python/commit/9b8a4aad6fe65ef37885e5c3368d2799a2666534))
 * Add span for context caching handling and new cache creation ([a2d9f13](https://github.com/google/adk-python/commit/a2d9f13fa1d31e00ba9493fba321ca151cdd9366))
 * Disable the scheduled execution for issue triage workflow ([bae2102](https://github.com/google/adk-python/commit/bae21027d9bd7f811bed638ecce692262cb33fe5))
 * Correct the callback signatures ([fa84bcb](https://github.com/google/adk-python/commit/fa84bcb5756773eadff486b99c9bd416b4faa9c6))
@@ -204,7 +202,7 @@
   * Add `dry_run` functionality to BigQuery `execute_sql` tool ([960eda3](https://github.com/google/adk-python/commit/960eda3d1f2f46dc93a365eb3de03dc3483fe9bb))
   * Add BigQuery analyze_contribution tool ([4bb089d](https://github.com/google/adk-python/commit/4bb089d386d4e8133e9aadbba5c42d31ff281cf6))
   * Spanner ADK toolset supports customizable template SQL and parameterized SQL ([da62700](https://github.com/google/adk-python/commit/da62700d739cb505149554962a8bcfb30f9428cc))
-  * Support OAuth2 client credentials grant type ([5c6cdcd](https://github.com/google/adk-python/commit/5c6cdcd197a6780fc86d9183fa208f78c8a975d9))
+  * Support Oauth2 client credentials grant type ([5c6cdcd](https://github.com/google/adk-python/commit/5c6cdcd197a6780fc86d9183fa208f78c8a975d9))
   * Add `ReflectRetryToolPlugin` to reflect from errors and retry with different arguments when tool errors ([e55b894](https://github.com/google/adk-python/commit/e55b8946d6a2e01aaf018d6a79d11d13c5286152))
   * Support using `VertexAiSearchTool` built-in tool with other tools in the same agent ([4485379](https://github.com/google/adk-python/commit/4485379a049a5c84583a43c85d444ea1f1ba6f12))
   * Support using google search built-in tool with other tools in the same agent ([d3148da](https://github.com/google/adk-python/commit/d3148dacc97f0a9a39b6d7a9640f7b7b0d6f9a6c))
@@ -285,7 +283,7 @@
   * Add endpoint to generate memory from session ([2595824](https://github.com/google/adk-python/commit/25958242db890b4d2aac8612f7f7cfbb561727fa))
 * **[Tools]**
   * Add Google Maps Grounding Tool to ADK ([6b49391](https://github.com/google/adk-python/commit/6b493915469ecb42068e24818ab547b0856e4709))
-  * **MCP:** Initialize tool_name_prefix in MCPToolset ([86dea5b](https://github.com/google/adk-python/commit/86dea5b53ac305367283b7e353b60d0f4515be3b))
+  * **MCP:** Initialize tool_name_prefix in MCPToolse ([86dea5b](https://github.com/google/adk-python/commit/86dea5b53ac305367283b7e353b60d0f4515be3b))
 * **[Evals]**
   * Data model for storing App Details and data model for steps ([01923a9](https://github.com/google/adk-python/commit/01923a9227895906ca8ae32712d65b178e2cd7d5))
   * Adds Rubric based final response evaluator ([5a485b0](https://github.com/google/adk-python/commit/5a485b01cd64cb49735e13ebd5e7fa3da02cd85f))
@@ -352,7 +350,7 @@
 * Fix discussion answering github action workflow to escape the quote in the discussion content JSON [43c9681](https://github.com/google/adk-python/commit/43c96811da891a5b0c9cf1be525665e65f346a13)
 * Send full MIME types for image/video/pdf in get_content [e45c3be](https://github.com/google/adk-python/commit/e45c3be23895b5ec68908ad9ee19bd622dcbd003)
 * Fix flaky unit tests: tests/unittests/flows/llm_flows/test_functions_simple.py [b92b288](https://github.com/google/adk-python/commit/b92b288c978a9b3d1a76c8bcb96cc8f439ce610b)
-* Make UT of a2a consistent about how tests should be skipped when python version < 3.10 [98b0426](https://github.com/google/adk-python/commit/98b0426cd2dc5e28014ead22b22dbf50d42d0a9a)
+* Make UT of a2a consistent about how tests should be skipped when python verison < 3.10 [98b0426](https://github.com/google/adk-python/commit/98b0426cd2dc5e28014ead22b22dbf50d42d0a9a)
 
 ### Improvements
 
@@ -443,7 +441,7 @@ with Bigtable for building AI Agent applications(experimental feature) ([a953807
 * Using base event's invocation id when merge multiple function response event ([279e4fe](https://github.com/google/adk-python/commit/279e4fedd0b1c0d1499c0f9a4454357af7da490e))
 * Avoid crash when there is no candidates_token_count, which is Optional ([22f34e9](https://github.com/google/adk-python/commit/22f34e9d2c552fbcfa15a672ef6ff0c36fa32619))
 * Fix the packaging version comparison logic in adk cli ([a2b7909](https://github.com/google/adk-python/commit/a2b7909fc36e7786a721f28e2bf75a1e86ad230d))
-* Add Spanner admin scope to Spanner tool default OAuth scopes ([b66054d](https://github.com/google/adk-python/commit/b66054dd0d8c5b3d6f6ad58ac1fbd8128d1da614))
+* Add Spanner admin scope to Spanner tool default Oauth scopes ([b66054d](https://github.com/google/adk-python/commit/b66054dd0d8c5b3d6f6ad58ac1fbd8128d1da614))
 * Fixes SequentialAgent.config_type type hint ([8a9a271](https://github.com/google/adk-python/commit/8a9a271141678996c9b84b8c55d4b539d011391c))
 * Fixes the host in the ansi bracket of adk web ([cd357bf](https://github.com/google/adk-python/commit/cd357bf5aeb01f1a6ae2a72349a73700ca9f1ed2))
 * Add spanner tool name prefix ([a27927d](https://github.com/google/adk-python/commit/a27927dc8197c391c80acb8b2c23d610fba2f887))
@@ -455,7 +453,7 @@ with Bigtable for building AI Agent applications(experimental feature) ([a953807
 * Update `openai` dependency version, based on correct OPENAI release ([bb8ebd1](https://github.com/google/adk-python/commit/bb8ebd15f90768b518cd0e21a59b269e30d6d944))
 * Add the missing license header for core_callback_config init file ([f8fd6a4](https://github.com/google/adk-python/commit/f8fd6a4f09ab520b8ecdbd8f9fe48228dbff7ebe))
 * Creates yaml_utils.py in utils to allow adk dump yaml in the same style ([1fd58cb](https://github.com/google/adk-python/commit/1fd58cb3633992cd88fa7e09ca6eda0f9b34236f))
-* Return explicit None type for DELETE endpoints ([f03f167](https://github.com/google/adk-python/commit/f03f1677790c0a9e59b6ba6f46010d0b7b64be50))
+* Return explict None type for DELETE endpoints ([f03f167](https://github.com/google/adk-python/commit/f03f1677790c0a9e59b6ba6f46010d0b7b64be50))
 * Add _config suffix to all yaml-based agent examples ([43f302c](https://github.com/google/adk-python/commit/43f302ce1ab53077ee8f1486d5294540678921e6))
 * Rename run related method and request to align with the conventions ([ecaa7b4](https://github.com/google/adk-python/commit/ecaa7b4c9847b478c7cdc37185b1525f733bb403))
 * Update models in samples/ folder to be gemini 2.0+ ([6c217ba](https://github.com/google/adk-python/commit/6c217bad828edf62b41ec06b168f8a6cb7ece2ed))
@@ -480,7 +478,7 @@ with Bigtable for building AI Agent applications(experimental feature) ([a953807
 
 ### Bug Fixes
 
-* A2A RPC URL got overridden by host and port param of adk api server ([52284b1](https://github.com/google/adk-python/commit/52284b1bae561e0d6c93c9d3240a09f210551b97))
+* A2A RPC URL got overriden by host and port param of adk api server ([52284b1](https://github.com/google/adk-python/commit/52284b1bae561e0d6c93c9d3240a09f210551b97))
 * Aclose all async generators to fix OTel tracing context ([a30c63c](https://github.com/google/adk-python/commit/a30c63c5933a770b960b08a6e2f8bf13eece8a22))
 * Use PreciseTimestamp for create and update time in database session service to improve precision ([585141e](https://github.com/google/adk-python/commit/585141e0b7dda20abb024c7164073862c8eea7ae))
 * Ignore AsyncGenerator return types in function declarations ([e2518dc](https://github.com/google/adk-python/commit/e2518dc371fe77d7b30328d8d6f5f864176edeac))
@@ -508,7 +506,7 @@ with Bigtable for building AI Agent applications(experimental feature) ([a953807
 * Group FastAPI endpoints with tags ([c323de5](https://github.com/google/adk-python/commit/c323de5c692223e55372c3797e62d4752835774d))
 * Allow implementations to skip defining a close method on Toolset ([944e39e](https://github.com/google/adk-python/commit/944e39ec2a7c9ad7f20c08fd66bf544de94a23d7))
 * Add sample agent to test support of output_schema and tools at the same time for gemini model ([f2005a2](https://github.com/google/adk-python/commit/f2005a20267e1ee8581cb79c37aa55dc8e18c0ea))
-* Add GitHub workflow config for uploading ADK docs to knowledge store ([5900273](https://github.com/google/adk-python/commit/59002734559d49a46940db9822b9c5f490220a8c))
+* Add Github workflow config for uploading ADK docs to knowledge store ([5900273](https://github.com/google/adk-python/commit/59002734559d49a46940db9822b9c5f490220a8c))
 * Update ADK Answering agent to reference doc site instead of adk-docs repo ([b5a8bad](https://github.com/google/adk-python/commit/b5a8bad170e271b475385dac440c7983ed207df8))
 
 ### Documentation

CONTRIBUTING.md

@@ -145,7 +145,7 @@ part before or alongside your code PR.
 
 3.  **Create and activate a virtual environment:**
 
-    **NOTE**: ADK supports Python 3.10+. Python 3.11 and above is strongly
+    **NOTE**: ADK supports Python 3.9+. Python 3.11 and above is strongly
     recommended.
 
     Create a workspace venv using uv.

README.md

@@ -17,8 +17,7 @@
       Important Links:
       <a href="https://google.github.io/adk-docs/">Docs</a>,
       <a href="https://github.com/google/adk-samples">Samples</a>,
-      <a href="https://github.com/google/adk-java">Java ADK</a>,
-      <a href="https://github.com/google/adk-go">Go ADK</a> &
+      <a href="https://github.com/google/adk-java">Java ADK</a> &
       <a href="https://github.com/google/adk-web">ADK Web</a>.
     </h3>
 </html>
@@ -33,7 +32,7 @@ deployment-agnostic, and compatible with other frameworks.
 
 ## 🔥 What's new
 
-- **Custom Service Registration**: Add a service registry to provide a generic way to register custom service implementations to be used in FastAPI server. See [short instruction](https://github.com/google/adk-python/discussions/3175#discussioncomment-14745120). ([391628f](https://github.com/google/adk-python/commit/391628fcdc7b950c6835f64ae3ccab197163c990))
+- **Custom Service Registration**: Add a service registry to provide a generic way to register custom service implementations to be used in FastAPI server. See short instruction [here](https://github.com/google/adk-python/discussions/3175#discussioncomment-14745120). ([391628f](https://github.com/google/adk-python/commit/391628fcdc7b950c6835f64ae3ccab197163c990))
 
 - **Rewind**: Add the ability to rewind a session to before a previous invocation ([9dce06f](https://github.com/google/adk-python/commit/9dce06f9b00259ec42241df4f6638955e783a9d1)).
 

contributing/samples/adk_agent_builder_assistant/__init__.py

@@ -18,10 +18,9 @@ This package provides an intelligent assistant for building multi-agent systems
 using YAML configurations. It can be used directly as an agent or integrated
 with ADK tools and web interfaces.
 """
-from __future__ import annotations
 
 from . import agent  # Import to make agent.root_agent available
-from .adk_agent_builder_assistant import AgentBuilderAssistant
+from .agent_builder_assistant import AgentBuilderAssistant
 
 __all__ = [
     'AgentBuilderAssistant',

contributing/samples/adk_agent_builder_assistant/agent.py

@@ -13,9 +13,8 @@
 # limitations under the License.
 
 """Agent Builder Assistant instance for ADK web testing."""
-from __future__ import annotations
 
-from .adk_agent_builder_assistant import AgentBuilderAssistant
+from .agent_builder_assistant import AgentBuilderAssistant
 
 # Create the agent instance using the factory
 # The root_agent variable is what ADK looks for when loading agents

contributing/samples/adk_agent_builder_assistant/agent_builder_assistant.py

@@ -0,0 +1,216 @@
+# 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.
+
+"""Agent factory for creating Agent Builder Assistant with embedded schema."""
+
+from pathlib import Path
+from typing import Callable
+from typing import Optional
+from typing import Union
+
+from google.adk.agents import LlmAgent
+from google.adk.agents.readonly_context import ReadonlyContext
+from google.adk.models import BaseLlm
+from google.adk.tools import AgentTool
+from google.adk.tools import FunctionTool
+from google.genai import types
+
+from .sub_agents.google_search_agent import create_google_search_agent
+from .sub_agents.url_context_agent import create_url_context_agent
+from .tools.cleanup_unused_files import cleanup_unused_files
+from .tools.delete_files import delete_files
+from .tools.explore_project import explore_project
+from .tools.read_config_files import read_config_files
+from .tools.read_files import read_files
+from .tools.search_adk_knowledge import search_adk_knowledge
+from .tools.search_adk_source import search_adk_source
+from .tools.write_config_files import write_config_files
+from .tools.write_files import write_files
+from .utils import load_agent_config_schema
+
+
+class AgentBuilderAssistant:
+  """Agent Builder Assistant factory for creating configured instances."""
+
+  @staticmethod
+  def create_agent(
+      model: Union[str, BaseLlm] = "gemini-2.5-flash",
+      working_directory: Optional[str] = None,
+  ) -> LlmAgent:
+    """Create Agent Builder Assistant with embedded ADK AgentConfig schema.
+
+    Args:
+      model: Model to use for the assistant (default: gemini-2.5-flash)
+      working_directory: Working directory for path resolution (default: current
+        working directory)
+
+    Returns:
+      Configured LlmAgent with embedded ADK AgentConfig schema
+    """
+    # Load full ADK AgentConfig schema directly into instruction context
+    instruction = AgentBuilderAssistant._load_instruction_with_schema(model)
+
+    # TOOL ARCHITECTURE: Hybrid approach using both AgentTools and FunctionTools
+    #
+    # Why use sub-agents for built-in tools?
+    # - ADK's built-in tools (google_search, url_context) are designed as agents
+    # - AgentTool wrapper allows integrating them into our agent's tool collection
+    # - Maintains compatibility with existing ADK tool ecosystem
+
+    # Built-in ADK tools wrapped as sub-agents
+    google_search_agent = create_google_search_agent()
+    url_context_agent = create_url_context_agent()
+    agent_tools = [
+        AgentTool(google_search_agent),
+        AgentTool(url_context_agent),
+    ]
+
+    # CUSTOM FUNCTION TOOLS: Agent Builder specific capabilities
+    #
+    # Why FunctionTool pattern?
+    # - Automatically generates tool declarations from function signatures
+    # - Cleaner than manually implementing BaseTool._get_declaration()
+    # - Type hints and docstrings become tool descriptions automatically
+
+    # Core agent building tools
+    custom_tools = [
+        FunctionTool(read_config_files),  # Read/parse multiple YAML configs
+        FunctionTool(
+            write_config_files
+        ),  # Write/validate multiple YAML configs
+        FunctionTool(explore_project),  # Analyze project structure
+        # File management tools (multi-file support)
+        FunctionTool(read_files),  # Read multiple files
+        FunctionTool(write_files),  # Write multiple files
+        FunctionTool(delete_files),  # Delete multiple files
+        FunctionTool(cleanup_unused_files),
+        # ADK source code search (regex-based)
+        FunctionTool(search_adk_source),  # Search ADK source with regex
+        # ADK knowledge search
+        FunctionTool(search_adk_knowledge),  # Search ADK knowledge base
+    ]
+
+    # Combine all tools
+    all_tools = agent_tools + custom_tools
+
+    # Create agent directly using LlmAgent constructor
+    agent = LlmAgent(
+        name="agent_builder_assistant",
+        description=(
+            "Intelligent assistant for building ADK multi-agent systems "
+            "using YAML configurations"
+        ),
+        instruction=instruction,
+        model=model,
+        tools=all_tools,
+        generate_content_config=types.GenerateContentConfig(
+            max_output_tokens=8192,
+        ),
+    )
+
+    return agent
+
+  @staticmethod
+  def _load_schema() -> str:
+    """Load ADK AgentConfig.json schema content and format for YAML embedding."""
+
+    # CENTRALIZED ADK AGENTCONFIG SCHEMA LOADING: Use common utility function
+    # This avoids duplication across multiple files and provides consistent
+    # ADK AgentConfig schema loading with caching and error handling.
+    schema_content = load_agent_config_schema(
+        raw_format=True,  # Get as JSON string
+    )
+
+    # Format as indented code block for instruction embedding
+    #
+    # Why indentation is needed:
+    # - The ADK AgentConfig schema gets embedded into instruction templates using .format()
+    # - Proper indentation maintains readability in the final instruction
+    # - Code block markers (```) help LLMs recognize this as structured data
+    #
+    # Example final instruction format:
+    #   "Here is the ADK AgentConfig schema:
+    #   ```json
+    #     {"type": "object", "properties": {...}}
+    #   ```"
+    lines = schema_content.split("\n")
+    indented_lines = ["  " + line for line in lines]  # 2-space indent
+    return "```json\n" + "\n".join(indented_lines) + "\n  ```"
+
+  @staticmethod
+  def _load_instruction_with_schema(
+      model: Union[str, BaseLlm],
+  ) -> Callable[[ReadonlyContext], str]:
+    """Load instruction template and embed ADK AgentConfig schema content."""
+    instruction_template = (
+        AgentBuilderAssistant._load_embedded_schema_instruction_template()
+    )
+    schema_content = AgentBuilderAssistant._load_schema()
+
+    # Get model string for template replacement
+    model_str = (
+        str(model)
+        if isinstance(model, str)
+        else getattr(model, "model_name", str(model))
+    )
+
+    # Return a function that accepts ReadonlyContext and returns the instruction
+    def instruction_provider(context: ReadonlyContext) -> str:
+      # Extract project folder name from session state
+      project_folder_name = AgentBuilderAssistant._extract_project_folder_name(
+          context
+      )
+
+      # Fill the instruction template with all variables
+      instruction_text = instruction_template.format(
+          schema_content=schema_content,
+          default_model=model_str,
+          project_folder_name=project_folder_name,
+      )
+      return instruction_text
+
+    return instruction_provider
+
+  @staticmethod
+  def _extract_project_folder_name(context: ReadonlyContext) -> str:
+    """Extract project folder name from session state using resolve_file_path."""
+    from .utils.resolve_root_directory import resolve_file_path
+
+    session_state = context._invocation_context.session.state
+
+    # Use resolve_file_path to get the full resolved path for "."
+    # This handles all the root_directory resolution logic consistently
+    resolved_path = resolve_file_path(".", session_state)
+
+    # Extract the project folder name from the resolved path
+    project_folder_name = resolved_path.name
+
+    # Fallback to "project" if we somehow get an empty name
+    if not project_folder_name:
+      project_folder_name = "project"
+
+    return project_folder_name
+
+  @staticmethod
+  def _load_embedded_schema_instruction_template() -> str:
+    """Load instruction template for embedded ADK AgentConfig schema mode."""
+    template_path = Path(__file__).parent / "instruction_embedded.template"
+
+    if not template_path.exists():
+      raise FileNotFoundError(
+          f"Instruction template not found at {template_path}"
+      )
+
+    with open(template_path, "r", encoding="utf-8") as f:
+      return f.read()

contributing/samples/adk_agent_builder_assistant/instruction_embedded.template

@@ -75,9 +75,6 @@ Always reference this schema when creating configurations to ensure compliance.
 - **CRITICAL TIMING**: Ask for model selection IMMEDIATELY after determining LlmAgent is needed, BEFORE presenting any design
 - **MANDATORY CONFIRMATION**: Say "Please confirm what model you want to use" - do NOT assume or suggest defaults
 - **EXAMPLES**: "gemini-2.5-flash", "gemini-2.5-pro", etc.
-- **ALLOWED MODELS ONLY**: Only mention or propose "gemini-2.5-flash" or
-  "gemini-2.5-pro". Treat any request for gemini-1.5-* or older models as
-  unsupported and redirect to one of the 2.5 options.
 - **RATIONALE**: Only LlmAgent requires model specification; workflow agents do not
 - **DEFAULT MODEL**: If user says "use default" or "proceed with default model", use: {default_model}
   * This is the actual model name, NOT the literal string "default"

contributing/samples/adk_agent_builder_assistant/sub_agents/__init__.py

@@ -13,7 +13,6 @@
 # limitations under the License.
 
 """Sub-agents for Agent Builder Assistant."""
-from __future__ import annotations
 
 from .google_search_agent import create_google_search_agent
 from .url_context_agent import create_url_context_agent

contributing/samples/adk_agent_builder_assistant/sub_agents/google_search_agent.py

@@ -13,7 +13,6 @@
 # limitations under the License.
 
 """Sub-agent for Google Search functionality."""
-from __future__ import annotations
 
 from google.adk.agents import LlmAgent
 from google.adk.tools import google_search

contributing/samples/adk_agent_builder_assistant/sub_agents/url_context_agent.py

@@ -13,7 +13,6 @@
 # limitations under the License.
 
 """Sub-agent for URL context fetching functionality."""
-from __future__ import annotations
 
 from google.adk.agents import LlmAgent
 from google.adk.tools import url_context

contributing/samples/adk_agent_builder_assistant/tools/__init__.py

@@ -13,7 +13,6 @@
 # limitations under the License.
 
 """Tools for Agent Builder Assistant."""
-from __future__ import annotations
 
 from .cleanup_unused_files import cleanup_unused_files
 from .delete_files import delete_files

contributing/samples/adk_agent_builder_assistant/tools/cleanup_unused_files.py

@@ -14,9 +14,10 @@
 
 """Cleanup unused files tool for Agent Builder Assistant."""
 
-from __future__ import annotations
-
 from typing import Any
+from typing import Dict
+from typing import List
+from typing import Optional
 
 from google.adk.tools.tool_context import ToolContext
 
@@ -25,11 +26,11 @@ from ..utils.resolve_root_directory import resolve_file_paths
 
 
 async def cleanup_unused_files(
-    used_files: list[str],
+    used_files: List[str],
     tool_context: ToolContext,
-    file_patterns: list[str] | None = None,
-    exclude_patterns: list[str] | None = None,
-) -> dict[str, Any]:
+    file_patterns: Optional[List[str]] = None,
+    exclude_patterns: Optional[List[str]] = None,
+) -> Dict[str, Any]:
   """Identify and optionally delete unused files in project directories.
 
   This tool helps clean up unused tool files when agent configurations change.

contributing/samples/adk_agent_builder_assistant/tools/delete_files.py

@@ -13,7 +13,6 @@
 # limitations under the License.
 
 """File deletion tool for Agent Builder Assistant."""
-from __future__ import annotations
 
 from datetime import datetime
 from pathlib import Path

contributing/samples/adk_agent_builder_assistant/tools/explore_project.py

@@ -13,7 +13,6 @@
 # limitations under the License.
 
 """Project explorer tool for analyzing structure and suggesting file paths."""
-from __future__ import annotations
 
 from pathlib import Path
 from typing import Any

contributing/samples/adk_agent_builder_assistant/tools/query_schema.py

@@ -13,7 +13,6 @@
 # limitations under the License.
 
 """ADK AgentConfig schema query tool for dynamic schema information access."""
-from __future__ import annotations
 
 from typing import Any
 from typing import Dict

contributing/samples/adk_agent_builder_assistant/tools/read_config_files.py

@@ -13,7 +13,6 @@
 # limitations under the License.
 
 """Configuration file reader tool for existing YAML configs."""
-from __future__ import annotations
 
 from pathlib import Path
 from typing import Any

contributing/samples/adk_agent_builder_assistant/tools/read_files.py

@@ -13,7 +13,6 @@
 # limitations under the License.
 
 """File reading tool for Agent Builder Assistant."""
-from __future__ import annotations
 
 from pathlib import Path
 from typing import Any