[FEATURE] MCP ToolResult `meta` field is missing

[Mashiro2000]

Problem Statement

In the MCP server, I use the meta field to pass some business-related fields, but I found that when using the AWS Strands SDK's MCP tool, themeta field is ignored. Will support for passing this field be added in the future?

See MCP specification
for notes on _meta usage.

Proposed Solution

No response

Use Case

test_mcp= FastMCP("test_mcp")


@test_mcp.tool(
    name="xxxx",
    description="xxxx",
)
async def xxxx():
    try:

        token_usage = response.usage_metadata.total_token_count if response.usage_metadata else 0

        return TextContent(
            type="text",
            text=url,
            _meta={
                "token_usage": token_usage,
            }
        )
    except Exception as e:
        logger.error(f"{type(e).__name__}: {e}")
        raise e

Alternatives Solutions

No response

Additional Context

No response

[dbschmigelski]

Hi, marked this as ready for contribution. This should be fairly simple to include on the tool result since we've already introduced https://github.com/strands-agents/sdk-python/blob/main/src/strands/tools/mcp/mcp_types.py#L50. So it would be quite similar in how we handle the structured output.