Support MCP streamable http

[showenx]

With Streamable HTTP protocol updated
https://modelcontextprotocol.io/specification/2025-03-26/basic/transports#streamable-http

Can we expand SseServerParams or add a new protocol type to support that?
https://google.github.io/adk-docs/tools/mcp-tools/#step-1-attach-the-fastmcp-server-to-your-adk-agent-via-mcptoolset

[omarbenhamid]

Hello @showenx here is a PR to implement streamable http MCPs, I added an new StreamableHTTPServerParams class as the current implementation of ADK uses isinstance() to determine the kind of client, so I did not want to derive too much. You can test and give me some feedback.

[showenx]

the mcp_toolet.py probably also needs updated
e.g. https://github.com/omarbenhamid/google-adk-python/blob/c5b9d49d7b6d858ff0a93bd690e6d653b7c32221/src/google/adk/tools/mcp_tool/mcp_toolset.py#L107

Basically using StreamableHTTPServerParams similar to SseServerParams
https://github.com/omarbenhamid/google-adk-python/blob/c5b9d49d7b6d858ff0a93bd690e6d653b7c32221/src/google/adk/tools/mcp_tool/mcp_toolset.py#L137-L139

[omarbenhamid]

The modifications in my repo were in a feature branch, I just emerged them back to main to make the discussion easier.

In fact mcp_toolset.py was updated, the two interfaces are in fact 90% similar. But I peferred keeping a consistent approach by creating a specific class. Tell me if you manage to test.

[showenx]

is this the main branch? https://github.com/omarbenhamid/google-adk-python

tried following, StreamableHTTPServerParams is not accessible
from google.adk.tools.mcp_tool.mcp_toolset import StreamableHTTPServerParams

[omarbenhamid]

You're right thanks, just fixed it now. (before you needed to import from mcp_session manager, which was not the target) you can pull again.

[showenx]

looking good, works for me on local build

[seanzhou1023]

@omarbenhamid thank you for your understanding and fix:)