Add resource Link

[ihrpr]

Details: modelcontextprotocol/modelcontextprotocol#603
Closes #944

---

• Added resource link to the tool output types
• Added a test to integrations tests

[bhosmer-ant]

Inline comment re Content/ContentBlock, but your call

[bhosmer-ant]

Assuming this is to reduce blast radius for the PR, but if so, should we maybe leave it named Content and then do the Content -> ContentBlock change in a followup, rather than having both names floating around?

[ihrpr]

need to add deprecated!

[bhosmer-ant]

per above comment

[bhosmer-ant]

per above comment

[ihrpr]

leaving content just in case someone uses it from SDK and not to break them

[bhosmer-ant]

LGTM!

[bhosmer-ant]

test failure looks like a linux flake?

[gw3] linux -- Python 3.11.12 /home/runner/work/python-sdk/python-sdk/.venv/bin/python

    @pytest.mark.anyio
    async def test_messages_are_executed_concurrently():
        server = FastMCP("test")
    
        @server.tool("sleep")
        async def sleep_tool():
            await anyio.sleep(_sleep_time_seconds)
            return "done"
    
        @server.resource(_resource_name)
        async def slow_resource():
            await anyio.sleep(_sleep_time_seconds)
            return "slow"
    
        async with create_session(server._mcp_server) as client_session:
            start_time = anyio.current_time()
            async with anyio.create_task_group() as tg:
                for _ in range(10):
                    tg.start_soon(client_session.call_tool, "sleep")
                    tg.start_soon(client_session.read_resource, AnyUrl(_resource_name))
    
            end_time = anyio.current_time()
    
            duration = end_time - start_time
>           assert duration < 10 * _sleep_time_seconds
E           assert 0.10288924399999644 < (10 * 0.01)