test: declare capabilities the notification tests rely on

Nine notification tests sent capability-gated messages (log, resource_updated,
roots/list_changed, *_list_changed) from a peer that had not declared the
capability, which only works because the SDK does not yet enforce capability
gating. Adding stub handlers / list_roots_callback so the capability is
advertised makes the tests match their requirement preconditions and survive
the gate fix unchanged.

The three list_changed tests cannot set listChanged=True without threading
NotificationOptions through the in-memory and HTTP-manager connection paths;
the requirement behavior text now describes what the tests prove (send ->
arrives) and the module docstring records the remaining coupling on
lifecycle:capability:server-not-advertised.

Author: maxisbey

tests/interaction/_requirements.py

@@ -586,8 +586,8 @@ def __post_init__(self) -> None:
     "tools:list-changed": Requirement(
         source=f"{SPEC_BASE_URL}/server/tools#list-changed-notification",
         behavior=(
-            "When the tool set changes, a server that declared the tools listChanged capability sends "
-            "notifications/tools/list_changed and it reaches the client's handler."
+            "When the tool set changes, the server sends notifications/tools/list_changed and it reaches "
+            "the client's handler."
         ),
     ),
     "tools:list:basic": Requirement(
@@ -787,8 +787,8 @@ def __post_init__(self) -> None:
     "resources:list-changed": Requirement(
         source=f"{SPEC_BASE_URL}/server/resources#list-changed-notification",
         behavior=(
-            "When the resource set changes, a server that declared the resources listChanged capability "
-            "sends notifications/resources/list_changed and it reaches the client's handler."
+            "When the resource set changes, the server sends notifications/resources/list_changed and it "
+            "reaches the client's handler."
         ),
     ),
     "resources:list:basic": Requirement(
@@ -959,8 +959,8 @@ def __post_init__(self) -> None:
     "prompts:list-changed": Requirement(
         source=f"{SPEC_BASE_URL}/server/prompts#list-changed-notification",
         behavior=(
-            "When the prompt set changes, a server that declared the prompts listChanged capability sends "
-            "notifications/prompts/list_changed and it reaches the client's handler."
+            "When the prompt set changes, the server sends notifications/prompts/list_changed and it "
+            "reaches the client's handler."
         ),
     ),
     "prompts:list:basic": Requirement(

tests/interaction/lowlevel/test_flows.py

@@ -23,6 +23,7 @@
     ElicitRequestFormParams,
     ElicitRequestURLParams,
     ElicitResult,
+    EmptyResult,
     ListToolsResult,
     ReadResourceResult,
     ResourceLink,
@@ -167,7 +168,16 @@ async def call_tool(ctx: ServerRequestContext, params: types.CallToolRequestPara
             )
         return CallToolResult(content=[TextContent(text="contents")])
 
-    server = Server("gatekeeper", on_list_tools=_list_tools("read_files"), on_call_tool=call_tool)
+    async def set_logging_level(ctx: ServerRequestContext, params: types.SetLevelRequestParams) -> EmptyResult:
+        """Registered so the logging capability is advertised; the client never sets a level."""
+        raise NotImplementedError
+
+    server = Server(
+        "gatekeeper",
+        on_list_tools=_list_tools("read_files"),
+        on_call_tool=call_tool,
+        on_set_logging_level=set_logging_level,
+    )
 
     async def collect(message: IncomingMessage) -> None:
         if isinstance(message, ElicitCompleteNotification):

tests/interaction/lowlevel/test_list_changed.py

@@ -6,6 +6,12 @@
 as ``transports/test_streamable_http.py::test_unrelated_server_messages_arrive_on_the_standalone_stream``.
 The collector still records every message it receives, so the snapshot also proves nothing else
 was delivered.
+
+The servers register the parent capability (resources/prompts) so that part of the spec's
+precondition holds, but the ``listChanged`` sub-capability stays ``False``: ``NotificationOptions``
+is not threaded through any of the suite's connection paths. The tests therefore rely on the
+recorded ``lifecycle:capability:server-not-advertised`` divergence and will need updating
+alongside the fix that introduces capability gating.
 """
 
 import anyio
@@ -78,7 +84,13 @@ async def call_tool(ctx: ServerRequestContext, params: types.CallToolRequestPara
         await ctx.session.send_resource_list_changed()
         return CallToolResult(content=[TextContent(text="mounted")])
 
-    server = Server("registry", on_list_tools=list_tools, on_call_tool=call_tool)
+    async def list_resources(
+        ctx: ServerRequestContext, params: types.PaginatedRequestParams | None
+    ) -> types.ListResourcesResult:
+        """Registered so the resources capability is advertised; the client never lists resources."""
+        raise NotImplementedError
+
+    server = Server("registry", on_list_tools=list_tools, on_call_tool=call_tool, on_list_resources=list_resources)
 
     async with connect(server, message_handler=collect) as client:
         await client.call_tool("mount", {})
@@ -108,7 +120,13 @@ async def call_tool(ctx: ServerRequestContext, params: types.CallToolRequestPara
         await ctx.session.send_prompt_list_changed()
         return CallToolResult(content=[TextContent(text="learned")])
 
-    server = Server("registry", on_list_tools=list_tools, on_call_tool=call_tool)
+    async def list_prompts(
+        ctx: ServerRequestContext, params: types.PaginatedRequestParams | None
+    ) -> types.ListPromptsResult:
+        """Registered so the prompts capability is advertised; the client never lists prompts."""
+        raise NotImplementedError
+
+    server = Server("registry", on_list_tools=list_tools, on_call_tool=call_tool, on_list_prompts=list_prompts)
 
     async with connect(server, message_handler=collect) as client:
         await client.call_tool("learn", {})

tests/interaction/lowlevel/test_logging.py

@@ -76,7 +76,11 @@ async def call_tool(ctx: ServerRequestContext, params: types.CallToolRequestPara
         )
         return CallToolResult(content=[TextContent(text="done")])
 
-    server = Server("logger", on_list_tools=list_tools, on_call_tool=call_tool)
+    async def set_logging_level(ctx: ServerRequestContext, params: types.SetLevelRequestParams) -> EmptyResult:
+        """Registered so the logging capability is advertised; the client never sets a level."""
+        raise NotImplementedError
+
+    server = Server("logger", on_list_tools=list_tools, on_call_tool=call_tool, on_set_logging_level=set_logging_level)
 
     async with connect(server, logging_callback=collect) as client:
         result = await client.call_tool("chatty", {})
@@ -111,7 +115,11 @@ async def call_tool(ctx: ServerRequestContext, params: types.CallToolRequestPara
             )
         return CallToolResult(content=[TextContent(text="logged")])
 
-    server = Server("logger", on_list_tools=list_tools, on_call_tool=call_tool)
+    async def set_logging_level(ctx: ServerRequestContext, params: types.SetLevelRequestParams) -> EmptyResult:
+        """Registered so the logging capability is advertised; the client never sets a level."""
+        raise NotImplementedError
+
+    server = Server("logger", on_list_tools=list_tools, on_call_tool=call_tool, on_set_logging_level=set_logging_level)
 
     async with connect(server, logging_callback=collect) as client:
         await client.call_tool("siren", {})

tests/interaction/lowlevel/test_resources.py

@@ -281,7 +281,23 @@ async def call_tool(ctx: ServerRequestContext, params: types.CallToolRequestPara
         await ctx.session.send_resource_updated("file:///watched.txt")
         return CallToolResult(content=[TextContent(text="touched")])
 
-    server = Server("library", on_list_tools=list_tools, on_call_tool=call_tool)
+    async def list_resources(
+        ctx: ServerRequestContext, params: types.PaginatedRequestParams | None
+    ) -> ListResourcesResult:
+        """Registered so the resources capability is advertised; the client never lists resources."""
+        raise NotImplementedError
+
+    async def subscribe_resource(ctx: ServerRequestContext, params: types.SubscribeRequestParams) -> EmptyResult:
+        """Registered so the resources subscribe sub-capability is advertised; the client never subscribes."""
+        raise NotImplementedError
+
+    server = Server(
+        "library",
+        on_list_tools=list_tools,
+        on_call_tool=call_tool,
+        on_list_resources=list_resources,
+        on_subscribe_resource=subscribe_resource,
+    )
 
     async with connect(server, message_handler=collect) as client:
         await client.call_tool("touch", {})

tests/interaction/lowlevel/test_roots.py

@@ -154,7 +154,11 @@ async def roots_list_changed(ctx: ServerRequestContext, params: types.Notificati
 
     server = Server("rooted", on_roots_list_changed=roots_list_changed)
 
-    async with connect(server) as client:
+    async def list_roots(context: ClientRequestContext) -> ListRootsResult:
+        """Registered so the client declares the roots capability; the server never asks for roots."""
+        raise NotImplementedError
+
+    async with connect(server, list_roots_callback=list_roots) as client:
         await client.send_roots_list_changed()
         with anyio.fail_after(5):
             await delivered.wait()

tests/interaction/lowlevel/test_wire.py

@@ -15,7 +15,7 @@
 from inline_snapshot import snapshot
 
 from mcp import MCPError, types
-from mcp.client import ClientSession
+from mcp.client import ClientRequestContext, ClientSession
 from mcp.client._memory import InMemoryTransport
 from mcp.client.client import Client
 from mcp.server import Server, ServerRequestContext
@@ -33,6 +33,7 @@
     JSONRPCNotification,
     JSONRPCRequest,
     JSONRPCResponse,
+    ListRootsResult,
     TextContent,
 )
 from tests.interaction._helpers import RecordingTransport, _RecordingReadStream
@@ -87,9 +88,14 @@ async def test_notifications_are_never_answered() -> None:
     the messages received from the server must be exactly one response per request, each carrying
     the id of the request it answers, and nothing else.
     """
+
+    async def list_roots(context: ClientRequestContext) -> ListRootsResult:
+        """Registered so the client declares the roots capability; the server never asks for roots."""
+        raise NotImplementedError
+
     recording = RecordingTransport(InMemoryTransport(_echo_server()))
 
-    async with Client(recording) as client:
+    async with Client(recording, list_roots_callback=list_roots) as client:
         await client.send_roots_list_changed()
         await client.send_ping()
 

tests/interaction/transports/_stdio_server.py

@@ -15,8 +15,10 @@
 from mcp.types import (
     CallToolRequestParams,
     CallToolResult,
+    EmptyResult,
     ListToolsResult,
     PaginatedRequestParams,
+    SetLevelRequestParams,
     TextContent,
     Tool,
 )
@@ -41,7 +43,12 @@ async def call_tool(ctx: ServerRequestContext, params: CallToolRequestParams) ->
     return CallToolResult(content=[TextContent(text=text)])
 
 
-server = Server("stdio-echo", on_list_tools=list_tools, on_call_tool=call_tool)
+async def set_logging_level(ctx: ServerRequestContext, params: SetLevelRequestParams) -> EmptyResult:
+    """Registered so the logging capability is advertised; the client never sets a level."""
+    raise NotImplementedError
+
+
+server = Server("stdio-echo", on_list_tools=list_tools, on_call_tool=call_tool, on_set_logging_level=set_logging_level)
 
 
 async def main() -> None:

tests/interaction/transports/test_hosting_http.py

@@ -19,12 +19,16 @@
     PARSE_ERROR,
     CallToolRequestParams,
     CallToolResult,
+    EmptyResult,
     JSONRPCError,
     JSONRPCNotification,
     JSONRPCRequest,
     JSONRPCResponse,
+    ListResourcesResult,
     ListToolsResult,
     PaginatedRequestParams,
+    SetLevelRequestParams,
+    SubscribeRequestParams,
     TextContent,
 )
 from tests.interaction._connect import (
@@ -52,7 +56,26 @@ async def call_tool(ctx: ServerRequestContext, params: CallToolRequestParams) ->
         await ctx.session.send_resource_updated("file:///watched.txt")
         return CallToolResult(content=[TextContent(text="done")])
 
-    return Server("hosted", on_list_tools=list_tools, on_call_tool=call_tool)
+    async def set_logging_level(ctx: ServerRequestContext, params: SetLevelRequestParams) -> EmptyResult:
+        """Registered so the logging capability is advertised; the client never sets a level."""
+        raise NotImplementedError
+
+    async def list_resources(ctx: ServerRequestContext, params: PaginatedRequestParams | None) -> ListResourcesResult:
+        """Registered so the resources capability is advertised; the client never lists resources."""
+        raise NotImplementedError
+
+    async def subscribe_resource(ctx: ServerRequestContext, params: SubscribeRequestParams) -> EmptyResult:
+        """Registered so the resources subscribe sub-capability is advertised; the client never subscribes."""
+        raise NotImplementedError
+
+    return Server(
+        "hosted",
+        on_list_tools=list_tools,
+        on_call_tool=call_tool,
+        on_set_logging_level=set_logging_level,
+        on_list_resources=list_resources,
+        on_subscribe_resource=subscribe_resource,
+    )
 
 
 @requirement("hosting:http:method-405")