PrefectAgent with gemini-3-pro-preview crashes

[jsmits]

Initial Checks

• I confirm that I'm using the latest version of Pydantic AI
• I confirm that I searched for my issue in https://github.com/pydantic/pydantic-ai/issues before opening this issue

Description

When I run my Prefect Agent with google-gla:gemini-3-pro-preview, it fails with AttributeError: 'GoogleModel' object has no attribute '_url'. It works fine with models from Anthropic and OpenAI. When I use that gemini model with a regular Agent in a Python shell, it also works fine.

Here's the traceback:

22:03:34.463 | ERROR   | prefect.engine - Execution of flow run 'bea4e0ee-e4cc-41a1-9fd4-fd7a6030fe9c' exited with unexpected exception
Traceback (most recent call last):
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/engine.py", line 57, in handle_engine_signals
    yield
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/flow_engine.py", line 1661, in run_flow_with_env
    asyncio.run(maybe_coro)
    ~~~~~~~~~~~^^^^^^^^^^^^
  File "/home/user/.pyenv/versions/3.13.7/lib/python3.13/asyncio/runners.py", line 195, in run
    return runner.run(main)
           ~~~~~~~~~~^^^^^^
  File "/home/user/.pyenv/versions/3.13.7/lib/python3.13/asyncio/runners.py", line 118, in run
    return self._loop.run_until_complete(task)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^
  File "/home/user/.pyenv/versions/3.13.7/lib/python3.13/asyncio/base_events.py", line 725, in run_until_complete
    return future.result()
           ~~~~~~~~~~~~~^^
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/flow_engine.py", line 1451, in run_flow_async
    return engine.state if return_type == "state" else await engine.result()
                                                       ^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/flow_engine.py", line 950, in result
    raise self._raised
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/flow_engine.py", line 1387, in run_context
    yield self
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/flow_engine.py", line 1449, in run_flow_async
    await engine.call_flow_fn()
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/flow_engine.py", line 1401, in call_flow_fn
    result = await call_with_parameters(self.flow.fn, self.parameters)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/src/prefect_flows/main.py", line 37, in main_flow
    links_result = await find_links(query_params)
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/flow_engine.py", line 1451, in run_flow_async
    return engine.state if return_type == "state" else await engine.result()
                                                       ^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/flow_engine.py", line 950, in result
    raise self._raised
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/flow_engine.py", line 1387, in run_context
    yield self
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/flow_engine.py", line 1449, in run_flow_async
    await engine.call_flow_fn()
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/flow_engine.py", line 1401, in call_flow_fn
    result = await call_with_parameters(self.flow.fn, self.parameters)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/src/prefect_flows/find_links.py", line 77, in find_links
    result = await prefect_agent.run(
             ^^^^^^^^^^^^^^^^^^^^^^^^
    ...<3 lines>...
    )
    ^
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/durable_exec/prefect/_agent.py", line 296, in run
    return await wrapped_run_flow()
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/flow_engine.py", line 1451, in run_flow_async
    return engine.state if return_type == "state" else await engine.result()
                                                       ^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/flow_engine.py", line 950, in result
    raise self._raised
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/flow_engine.py", line 1387, in run_context
    yield self
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/flow_engine.py", line 1449, in run_flow_async
    await engine.call_flow_fn()
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/flow_engine.py", line 1401, in call_flow_fn
    result = await call_with_parameters(self.flow.fn, self.parameters)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/durable_exec/prefect/_agent.py", line 277, in wrapped_run_flow
    result = await super(WrapperAgent, self).run(
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    ...<13 lines>...
    )
    ^
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/agent/abstract.py", line 225, in run
    async with self.iter(
               ~~~~~~~~~^
        user_prompt=user_prompt,
        ^^^^^^^^^^^^^^^^^^^^^^^^
    ...<10 lines>...
        builtin_tools=builtin_tools,
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    ) as agent_run:
    ^
  File "/home/user/.pyenv/versions/3.13.7/lib/python3.13/contextlib.py", line 235, in __aexit__
    await self.gen.athrow(value)
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/durable_exec/prefect/_agent.py", line 815, in iter
    async with super().iter(
               ~~~~~~~~~~~~^
        user_prompt=user_prompt,
        ^^^^^^^^^^^^^^^^^^^^^^^^
    ...<10 lines>...
        toolsets=toolsets,
        ^^^^^^^^^^^^^^^^^^
    ) as run:
    ^
  File "/home/user/.pyenv/versions/3.13.7/lib/python3.13/contextlib.py", line 235, in __aexit__
    await self.gen.athrow(value)
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/agent/wrapper.py", line 205, in iter
    async with self.wrapped.iter(
               ~~~~~~~~~~~~~~~~~^
        user_prompt=user_prompt,
        ^^^^^^^^^^^^^^^^^^^^^^^^
    ...<11 lines>...
        builtin_tools=builtin_tools,
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    ) as run:
    ^
  File "/home/user/.pyenv/versions/3.13.7/lib/python3.13/contextlib.py", line 235, in __aexit__
    await self.gen.athrow(value)
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/agent/__init__.py", line 649, in iter
    async with graph.iter(
               ~~~~~~~~~~^
        inputs=user_prompt_node,
        ^^^^^^^^^^^^^^^^^^^^^^^^
    ...<3 lines>...
        infer_name=False,
        ^^^^^^^^^^^^^^^^^
    ) as graph_run:
    ^
  File "/home/user/.pyenv/versions/3.13.7/lib/python3.13/contextlib.py", line 235, in __aexit__
    await self.gen.athrow(value)
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_graph/beta/graph.py", line 270, in iter
    async with GraphRun[StateT, DepsT, OutputT](
               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
        graph=self,
        ^^^^^^^^^^^
    ...<3 lines>...
        traceparent=traceparent,
        ^^^^^^^^^^^^^^^^^^^^^^^^
    ) as graph_run:
    ^
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_graph/beta/graph.py", line 423, in __aexit__
    await self._async_exit_stack.__aexit__(exc_type, exc_val, exc_tb)
  File "/home/user/.pyenv/versions/3.13.7/lib/python3.13/contextlib.py", line 768, in __aexit__
    raise exc
  File "/home/user/.pyenv/versions/3.13.7/lib/python3.13/contextlib.py", line 749, in __aexit__
    cb_suppress = cb(*exc_details)
  File "/home/user/.pyenv/versions/3.13.7/lib/python3.13/contextlib.py", line 162, in __exit__
    self.gen.throw(value)
    ~~~~~~~~~~~~~~^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_graph/beta/graph.py", line 978, in _unwrap_exception_groups
    raise exception
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_graph/beta/graph.py", line 750, in _run_tracked_task
    result = await self._run_task(t_)
             ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_graph/beta/graph.py", line 779, in _run_task
    output = await node.call(step_context)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_graph/beta/step.py", line 253, in _call_node
    return await node.run(GraphRunContext(state=ctx.state, deps=ctx.deps))
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/_agent_graph.py", line 548, in run
    async with self.stream(ctx):
               ~~~~~~~~~~~^^^^^
  File "/home/user/.pyenv/versions/3.13.7/lib/python3.13/contextlib.py", line 221, in __aexit__
    await anext(self.gen)
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/_agent_graph.py", line 562, in stream
    async for _event in stream:
        pass
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/_agent_graph.py", line 680, in _run_stream
    async for event in self._events_iterator:
        yield event
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/_agent_graph.py", line 641, in _run_stream
    async for event in self._handle_tool_calls(ctx, tool_calls):
        yield event
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/_agent_graph.py", line 696, in _handle_tool_calls
    async for event in process_tool_calls(
    ...<8 lines>...
        yield event
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/_agent_graph.py", line 894, in process_tool_calls
    async for event in _call_tools(
    ...<10 lines>...
        yield event
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/_agent_graph.py", line 1030, in _call_tools
    if event := await handle_call_or_result(coro_or_task=task, index=index):
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/_agent_graph.py", line 993, in handle_call_or_result
    (await coro_or_task) if inspect.isawaitable(coro_or_task) else coro_or_task.result()
     ^^^^^^^^^^^^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/_agent_graph.py", line 1066, in _call_tool
    tool_result = await tool_manager.handle_call(tool_call)
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/_tool_manager.py", line 119, in handle_call
    return await self._call_function_tool(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    ...<8 lines>...
    )
    ^
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/_tool_manager.py", line 250, in _call_function_tool
    tool_result = await self._call_tool(
                  ^^^^^^^^^^^^^^^^^^^^^^
    ...<4 lines>...
    )
    ^
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/_tool_manager.py", line 171, in _call_tool
    result = await self.toolset.call_tool(name, args_dict, ctx, tool)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/toolsets/combined.py", line 90, in call_tool
    return await tool.source_toolset.call_tool(name, tool_args, ctx, tool.source_tool)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/toolsets/combined.py", line 90, in call_tool
    return await tool.source_toolset.call_tool(name, tool_args, ctx, tool.source_tool)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/pydantic_ai/durable_exec/prefect/_mcp_server.py", line 58, in call_tool
    return await self._call_tool_task.with_options(name=f'Call MCP Tool: {name}', **self._task_config)(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        name, tool_args, ctx, tool
        ^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/task_engine.py", line 1561, in run_task_async
    async with engine.start(task_run_id=task_run_id, dependencies=dependencies):
               ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/.pyenv/versions/3.13.7/lib/python3.13/contextlib.py", line 214, in __aenter__
    return await anext(self.gen)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/task_engine.py", line 1410, in start
    async with self.initialize_run(
               ~~~~~~~~~~~~~~~~~~~^
        task_run_id=task_run_id, dependencies=dependencies
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    ):
    ^
  File "/home/user/.pyenv/versions/3.13.7/lib/python3.13/contextlib.py", line 214, in __aenter__
    return await anext(self.gen)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/task_engine.py", line 1328, in initialize_run
    self.task_run = await self.task.create_local_run(
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    ...<6 lines>...
    )
    ^
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/tasks.py", line 1020, in create_local_run
    k: collect_task_run_inputs_sync(v) for k, v in parameters.items()
       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/utilities/engine.py", line 161, in collect_task_run_inputs_sync
    visit_collection(
    ~~~~~~~~~~~~~~~~^
        expr,
        ^^^^^
    ...<2 lines>...
        max_depth=max_depth,
        ^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/utilities/collections.py", line 503, in visit_collection
    values = [visit_nested(getattr(expr, f.name)) for f in expr_fields]
              ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/utilities/collections.py", line 401, in visit_nested
    return visit_collection(
        expr,
    ...<4 lines>...
        _seen=_seen,
    )
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/utilities/collections.py", line 503, in visit_collection
    values = [visit_nested(getattr(expr, f.name)) for f in expr_fields]
              ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/utilities/collections.py", line 401, in visit_nested
    return visit_collection(
        expr,
    ...<4 lines>...
        _seen=_seen,
    )
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/utilities/collections.py", line 503, in visit_collection
    values = [visit_nested(getattr(expr, f.name)) for f in expr_fields]
              ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/utilities/collections.py", line 401, in visit_nested
    return visit_collection(
        expr,
    ...<4 lines>...
        _seen=_seen,
    )
  File "/home/user/.venv/lib/python3.13/site-packages/prefect/utilities/collections.py", line 503, in visit_collection
    values = [visit_nested(getattr(expr, f.name)) for f in expr_fields]
                           ~~~~~~~^^^^^^^^^^^^^^
AttributeError: 'GoogleModel' object has no attribute '_url'
22:03:37.953 | ERROR   | prefect.flow_runs.runner - Process for flow run 'flying-goldfish' exited with status code: 1

Example Code

Python, Pydantic AI & LLM client version

Python: 3.13.7
Pydantic AI: 1.20.0
LLM: Google (gemini-3-pro-review)
Prefect: 3.6.2

[DouweM]

@jsmits Thanks for the report.

@desertaxle Can you have a look at this please?

[japborst]

Not exactly the same issue, but reporting at least here (can spin out a new issue).

Using Gemini 3 leads to AttributeError: 'Client' object has no attribute 'base_url'.
This error is thrown from openai.py, is that expected?

File "/Users/japborst/Documents/dev/lex-os/backend/lexos/api/v1/endpoints/adapters.py", line 425, in run_agent
             │     result = await agent.agent.run(
             │              ^^^^^^^^^^^^^^^^^^^^^^
             │   File "/Users/japborst/Documents/dev/lex-os/backend/.venv/lib/python3.12/site-packages/pydantic_ai/agent/abstract.py", line 243, in run
             │     async with node.stream(agent_run.ctx) as stream:
             │                ^^^^^^^^^^^^^^^^^^^^^^^^^^
             │   File "/Users/japborst/.local/share/uv/python/cpython-3.12.9-macos-aarch64-none/lib/python3.12/contextlib.py", line 210, in __aenter__
             │     return await anext(self.gen)
             │            ^^^^^^^^^^^^^^^^^^^^^
             │   File "/Users/japborst/Documents/dev/lex-os/backend/.venv/lib/python3.12/site-packages/pydantic_ai/_agent_graph.py", line 434, in stream
             │     async with ctx.deps.model.request_stream(
             │                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
             │   File "/Users/japborst/.local/share/uv/python/cpython-3.12.9-macos-aarch64-none/lib/python3.12/contextlib.py", line 210, in __aenter__
             │     return await anext(self.gen)
             │            ^^^^^^^^^^^^^^^^^^^^^
             │   File "/Users/japborst/Documents/dev/lex-os/backend/.venv/lib/python3.12/site-packages/pydantic_ai/models/instrumented.py", line 388, in request_stream
             │     with self._instrument(messages, prepared_settings, prepared_parameters) as finish:
             │          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
             │   File "/Users/japborst/.local/share/uv/python/cpython-3.12.9-macos-aarch64-none/lib/python3.12/contextlib.py", line 137, in __enter__
             │     return next(self.gen)
             │            ^^^^^^^^^^^^^^
             │   File "/Users/japborst/Documents/dev/lex-os/backend/.venv/lib/python3.12/site-packages/pydantic_ai/models/instrumented.py", line 413, in _instrument
             │     **self.model_attributes(self.wrapped),
             │       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
             │   File "/Users/japborst/Documents/dev/lex-os/backend/.venv/lib/python3.12/site-packages/pydantic_ai/models/instrumented.py", line 494, in model_attributes
             │     if base_url := model.base_url:
             │                    ^^^^^^^^^^^^^^
             │   File "/Users/japborst/Documents/dev/lex-os/backend/.venv/lib/python3.12/site-packages/pydantic_ai/models/openai.py", line 976, in base_url
             │     return str(self.client.base_url)
             │                ^^^^^^^^^^^^^^^^^^^^
             │ AttributeError: 'Client' object has no attribute 'base_url'

Will try to create a minimum working example, as a very simple agent does work, e.g.

from pydantic_ai import Agent

agent = Agent(model="google-gla:gemini-3-pro-preview")

result = agent.run_sync(<prompt>)
print(result.output)

[DouweM]

@japborst There's definitely something weird happening there; there's no reason for openai.py to come into play when you're just using a Google model...

It smells to me like something may be going wrong in Prefect (de)serializing model classes and them being used in the wrong place?

[desertaxle]

Hey! I wasn't able to reproduce this issue with this script:

# /// script
# dependencies = [
#   "pydantic-ai-slim[google,prefect]"
# ]
# ///
import asyncio

from pydantic_ai import Agent
from pydantic_ai.durable_exec.prefect import PrefectAgent


async def main():
    agent = Agent(
        'google-gla:gemini-3-pro-preview',
        name='prefect-agent',
    )

    prefect_agent = PrefectAgent(
        agent,
    )
    result = await prefect_agent.run("What's the capital of France?")
    print(result.output)


if __name__ == '__main__':
    asyncio.run(main())

I was using the latest version of pydantic-ai and prefect, so I think it's worth investigating if this is a prefect version related issue.

@jsmits can you share what prefect version you're using and, if possible, a short script where you're seeing this issue?

[japborst]

@DouweM sorry Douwe! I was accidentally feeding in a Gemini model using the OpenAI model settings. So ignore my comment.

[DouweM]

@japborst Ok great, thanks!

@jsmits If you have a reproducible code example that'd be very helpful

[jsmits]

Yes, I was able to reproduce the error with the following code. The exception is raised when I use Gemini in combination with the tool. Gemini without the tool works just fine. But Sonnet with the tool also works fine. Don't know if Gemini fails with any tool, just tested it with this one, because that's what my code uses.

from prefect import flow
from pydantic_ai import Agent
from pydantic_ai.durable_exec.prefect import PrefectAgent
from pydantic_ai.mcp import MCPServerStdio


class PlaywrightMCP(MCPServerStdio):
    def __init__(self, **kwargs):
        super().__init__(
            command="npx",
            args=[
                "@playwright/mcp@latest",
                "--headless",
                "--isolated",
                "--executable-path",
                "/Applications/Chromium.app/Contents/MacOS/Chromium",
                "--user-agent",
                "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 "
                "(KHTML, like Gecko) Chrome/139.0.0.0 Safari/537.36",
            ],
            **kwargs,
        )


@flow
async def test_flow() -> None:
    # model = "anthropic:claude-sonnet-4-5-20250929"  # works
    model = "google-gla:gemini-3-pro-preview"  # does not work

    agent = Agent(
        model=model,
        toolsets=[
            PlaywrightMCP(max_retries=5)
        ],  # gemini works with this tool disabled/commented
        name="prefect-agent",
    )
    prefect_agent = PrefectAgent(agent)

    result = await prefect_agent.run("What's the capital of France?")
    print(result.output)


if __name__ == "__main__":
    test_flow.serve(name="test-flow")

[DouweM]

@jsmits Does it have to be that particular MCP server, or do you see the same issue with MCPServerStreamableHTTP(url='https://mcp.deepwiki.com/mcp', timeout=30)? (That's an auth-less MCP server that's useful for testing)

[jsmits]

@DouweM Just tried it, couldn't reproduce the error with the MCPServerStreamableHTTP MCP server. That one just worked without issues with Gemini.

[dorukgezici]

I experience the same issue AttributeError: 'GoogleModel' object has no attribute '_url' with a PrefectAgent that doesn't connect to any MCP servers, just a custom toolset I provided.