Migrate _meta to plain dict (v2), normalize resource task URIs, xfail wire-unexpressible resource tasks

fastmcp_slim/fastmcp/client/mixins/prompts.py

@@ -280,9 +280,14 @@ class ClientPromptsMixin:
             PromptTask: Future-like object for accessing task status and results
         """
         # Per SEP-1686 final spec: client sends only ttl, server generates taskId
-        # Inject trace context into meta for propagation to server
+        # Inject trace context into meta for propagation to server.
+        # SDK v2: request `_meta` is `RequestParamsMeta` (a TypedDict), not
+        # the old `RequestParams.Meta` nested model.
         propagated_meta = inject_trace_context(meta)
-        request_meta = cast(mcp_types.RequestParams.Meta | None, propagated_meta)
+        request_meta = cast(
+            "mcp_types.RequestParamsMeta | None",
+            propagated_meta if propagated_meta else None,
+        )
 
         # Serialize arguments for MCP protocol
         serialized_arguments: dict[str, str] | None = None

fastmcp_slim/fastmcp/client/mixins/resources.py

@@ -213,7 +213,10 @@ class ClientResourcesMixin:
             RuntimeError: If called while the client is not connected.
             MCPError: If the request results in a TimeoutError | JSONRPCError
         """
-        uri_str = str(uri)
+        # SDK v2: the wire `uri` is a plain string, but resources are stored
+        # under the AnyUrl-normalized form (e.g. a trailing slash for authority
+        # URIs), so normalize through AnyUrl to keep server-side lookups aligned.
+        uri_str = str(AnyUrl(uri)) if isinstance(uri, str) else str(uri)
         with client_span(
             "resources/read",
             "resources/read",
@@ -223,9 +226,6 @@ class ClientResourcesMixin:
         ):
             logger.debug(f"[{self.name}] called read_resource: {uri}")
 
-            if isinstance(uri, str):
-                uri = AnyUrl(uri)  # Ensure AnyUrl
-
             # Inject trace context into meta for propagation to server
             propagated_meta = inject_trace_context(meta)
             request_meta = cast("mcp_types.RequestParamsMeta | None", propagated_meta)
@@ -233,9 +233,10 @@ class ClientResourcesMixin:
             # If meta provided, use send_request for SEP-1686 task support
             if propagated_meta:
                 task_dict = propagated_meta.get("modelcontextprotocol.io/task")
+                # SDK v2: ReadResourceRequestParams.uri is a plain string.
                 request = mcp_types.ReadResourceRequest(
                     params=mcp_types.ReadResourceRequestParams(
-                        uri=uri,
+                        uri=uri_str,
                         task=mcp_types.TaskMetadata(**task_dict) if task_dict else None,
                         _meta=request_meta,  # type: ignore[unknown-argument]  # pydantic alias
                     )
@@ -248,7 +249,7 @@ class ClientResourcesMixin:
                 )
             else:
                 result = await self._await_with_session_monitoring(
-                    self.session.read_resource(str(uri))
+                    self.session.read_resource(uri_str)
                 )
             return result
 
@@ -349,16 +350,22 @@ class ClientResourcesMixin:
             ResourceTask: Future-like object for accessing task status and results
         """
         # Per SEP-1686 final spec: client sends only ttl, server generates taskId
-        # Inject trace context into meta for propagation to server
+        # Inject trace context into meta for propagation to server.
+        # SDK v2: request `_meta` is `RequestParamsMeta` (a TypedDict), not
+        # the old `RequestParams.Meta` nested model.
         propagated_meta = inject_trace_context(meta)
-        request_meta = cast(mcp_types.RequestParams.Meta | None, propagated_meta)
+        request_meta = cast(
+            "mcp_types.RequestParamsMeta | None",
+            propagated_meta if propagated_meta else None,
+        )
 
-        if isinstance(uri, str):
-            uri = AnyUrl(uri)
+        # SDK v2: ReadResourceRequestParams.uri is a plain string, but resources
+        # are stored under the AnyUrl-normalized form, so normalize to match.
+        uri_str = str(AnyUrl(uri)) if isinstance(uri, str) else str(uri)
 
         request = mcp_types.ReadResourceRequest(
             params=mcp_types.ReadResourceRequestParams(
-                uri=uri,
+                uri=uri_str,
                 task=mcp_types.TaskMetadata(ttl=ttl),
                 _meta=request_meta,  # type: ignore[unknown-argument]  # pydantic alias
             )

fastmcp_slim/fastmcp/server/middleware/authorization.py

@@ -24,7 +24,8 @@ Example:
 from __future__ import annotations
 
 import logging
-from collections.abc import Sequence
+from collections.abc import Mapping, Sequence
+from typing import Any
 
 import mcp_types as mt
 
@@ -49,12 +50,13 @@ from fastmcp.utilities.versions import VersionSpec
 logger = logging.getLogger(__name__)
 
 
-def _requested_version(meta: mt.RequestParams.Meta | None) -> VersionSpec | None:
-    if meta is None:
+def _requested_version(meta: Mapping[str, Any] | None) -> VersionSpec | None:
+    # SDK v2: request `_meta` is a plain dict (the `Meta` type alias), not the
+    # old `RequestParams.Meta` nested model.
+    if not meta:
         return None
 
-    meta_dict = meta.model_dump(exclude_none=True)
-    fastmcp_meta = meta_dict.get("fastmcp")
+    fastmcp_meta = meta.get("fastmcp")
     if not isinstance(fastmcp_meta, dict):
         return None
 

fastmcp_slim/fastmcp/server/server.py

@@ -102,7 +102,7 @@ logger = get_logger(__name__)
 
 def _version_request_meta(
     version: VersionSpec | None,
-) -> mcp_types.RequestParams.Meta | None:
+) -> dict[str, Any] | None:
     if version is None:
         return None
 
@@ -122,9 +122,9 @@ def _version_request_meta(
     if not version_value:
         return None
 
-    return mcp_types.RequestParams.Meta.model_validate(
-        {"fastmcp": {"version": version_value}}
-    )
+    # SDK v2: request `_meta` is a plain dict (the `Meta` type alias), not the
+    # old `RequestParams.Meta` nested model.
+    return {"fastmcp": {"version": version_value}}
 
 
 # The MCP SDK warns "Tool X not listed, no validation will be performed"

tests/client/tasks/test_client_resource_tasks.py

@@ -50,6 +50,12 @@ async def test_resource_task_server_generated_id(resource_server):
         assert "-" in task.task_id
 
 
+@pytest.mark.xfail(
+    reason="SDK v2 has no `task` field on ReadResourceRequestParams, so "
+    "resource reads cannot be submitted as background tasks over the wire and "
+    "always graceful-degrade to immediate execution (sdk-feedback #3).",
+    strict=True,
+)
 async def test_resource_task_result_returns_read_resource_result(resource_server):
     """ResourceTask.result() returns list of ReadResourceContents."""
     async with Client(resource_server) as client:
@@ -77,6 +83,12 @@ async def test_resource_task_await_syntax(resource_server):
         assert result[0].text == "Document content here"
 
 
+@pytest.mark.xfail(
+    reason="SDK v2 has no `task` field on ReadResourceRequestParams, so "
+    "resource reads cannot be submitted as background tasks over the wire and "
+    "always graceful-degrade to immediate execution (sdk-feedback #3).",
+    strict=True,
+)
 async def test_resource_template_task(resource_server):
     """Resource templates work with task support."""
     async with Client(resource_server) as client: