Function _get_function_tool_invoke_context

src/agents/tool.py:1772–1803

Choose the runtime context object to pass into a function tool wrapper. Third-party wrappers may declare a narrower `RunContextWrapper` contract and then serialize that object downstream. In those cases, passing the richer `ToolContext` can leak runtime-only metadata such as agents or r

(
    function_tool: FunctionTool,
    context: ToolContext[Any],
)

def _get_function_tool_invoke_context(
    function_tool: FunctionTool,
    context: ToolContext[Any],
) -> ToolContext[Any] | RunContextWrapper[Any]:
    """Choose the runtime context object to pass into a function tool wrapper.

    Third-party wrappers may declare a narrower `RunContextWrapper` contract and then serialize
    that object downstream. In those cases, passing the richer `ToolContext` can leak runtime-only
    metadata such as agents or run config into incompatible serializers. When the wrapper
    explicitly declares `RunContextWrapper`, preserve only the base context state.
    """
    try:
        parameters = tuple(inspect.signature(function_tool.on_invoke_tool).parameters.values())
    except (TypeError, ValueError):
        return context

    if not parameters:
        return context

    context_annotation = parameters[0].annotation
    try:
        resolved_annotations = get_type_hints(function_tool.on_invoke_tool, include_extras=True)
    except Exception:
        pass
    else:
        context_annotation = resolved_annotations.get(parameters[0].name, context_annotation)

    if _annotation_mentions_context_type(context_annotation, context_type=ToolContext):
        return context
    if _annotation_mentions_context_type(context_annotation, context_type=RunContextWrapper):
        return context._fork_with_tool_input(context.tool_input)
    return context


async def invoke_function_tool(