MCP background tasks (SEP-1686) support

[jimkont]

In the latest MCP release (https://modelcontextprotocol.io/specification/2025-11-25/changelog) there was a new addition for supporting background tasks:

Add experimental support for tasks to enable tracking durable requests with polling and deferred result retrieval (SEP-1686).

I tried to test this feature and I get Tool 'toon-name' requires task-augmented execution when adk hits the tool. Does ADK needs to build support for this new feature or is there some configuration on my side that can allow this?

[adk-bot]

Response from ADK Answering Agent (experimental, answer may be inaccurate)

TLDR: ADK does not currently support the new experimental MCP background tasks feature (SEP-1686). The error you are seeing is not due to a misconfiguration on your part, but because this feature requires specific implementation within the ADK framework which has not been added yet.

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Hi @jimkont,

Thank you for your question.

The new experimental support for background tasks (SEP-1686) in the Model Context Protocol (MCP) is a recent addition to the specification. As you've discovered, using a tool that requires this feature results in the error Tool 'toon-name' requires task-augmented execution.

This error indicates that the client-side of the connection (in this case, the ADK) needs to have special handling for the lifecycle of these tasks, such as polling for results and managing deferred retrieval. This functionality is not yet built into the ADK's McpToolset. New features in the MCP specification, especially experimental ones, require explicit implementation in the client libraries that use them.

While ADK has robust support for asynchronous operations and long-running tools [4, 7], this is distinct from the new background task protocol defined in SEP-1686.

Therefore, you are not missing any configuration. Support for this new MCP feature will need to be added to the ADK in a future release. I am adding the feature-request label to this discussion to track this.

[jimkont]

thanks for the reply @adk-bot! can you add the feature-request label? you mentioned that will add it but it is still missing

[adk-bot]

Response from ADK Answering Agent (experimental, answer may be inaccurate)

TLDR: While ADK has support for long-running operations via LongRunningFunctionTool, which is conceptually similar to background tasks, the specific MCP background tasks feature (SEP-1686) you are referring to seems to be a very recent addition to the MCP specification. It may not be fully integrated into the stable version of ADK yet. You might need to check the development version of ADK for the latest features.

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Hi @jimkont,

Thanks for your question. I see an answer has already been chosen for this discussion, but I'd like to provide some additional information that might be helpful.

ADK supports long-running or asynchronous operations through the LongRunningFunctionTool. [1] This is useful for tools that might take a long time to complete and would otherwise block the execution.

ADK also has robust support for MCP, allowing it to act as an MCP client to consume tools from an MCP server, or to expose its own tools via an MCP server. [2, 3]

The error message you're seeing, Tool 'toon-name' requires task-augmented execution, and the reference to SEP-1686 suggest that you're trying to use a feature that is very new in the MCP specification. It's possible that this feature is not yet fully supported in the stable version of ADK you are using.

I would recommend checking the development version of ADK to see if this feature is included there. You can install the development version using pip:

pip install git+https://github.com/google/adk-python.git

For more details, you can refer to the following documentation:

• Using Function Tools
• MCP Tools
• ADK Changelog

I hope this helps!

[1] https://google.github.io/adk-docs/tools-custom/function-tools/
[2] https://google.github.io/adk-docs/mcp/
[3] https://google.github.io/adk-docs/tools-custom/mcp-tools/