Tighten the cancellation-suite manifest provenance and wire pins

Author: maxisbey

tests/interaction/README.md

@@ -27,7 +27,10 @@ flows — with a single subprocess test for stdio.
   the constants in `mcp_types`; error *message strings* are pinned only where they are the
   SDK's own deliberate output.
 - **No sleeps, no real I/O.** Concurrency is coordinated with `anyio.Event`; every wait that
-  could hang is bounded by `anyio.fail_after(5)`. The HTTP and OAuth tests drive the Starlette
+  could hang is bounded by `anyio.fail_after(5)`. A test that must let in-flight deliveries
+  settle before teardown (an abandoned request's late error response, say) may use
+  `anyio.wait_all_tasks_blocked()`: the whole suite is single-loop and task-driven, so
+  quiescence is deterministic. The HTTP and OAuth tests drive the Starlette
   app in-process through the suite's streaming ASGI bridge (`transports/_bridge.py`), which
   delivers each response chunk as the server produces it — full duplex, but still no sockets,
   threads, or subprocesses anywhere outside the one stdio test.

tests/interaction/_requirements.py

@@ -475,11 +475,16 @@ def __post_init__(self) -> None:
         ),
     ),
     "protocol:request-id:caller-supplied": Requirement(
-        source=f"{SPEC_2026_BASE_URL}/basic/patterns/subscriptions#receiving-notifications",
+        source="sdk",
         behavior=(
             "A caller can supply the id of a request it sends, so the id is known before any response "
             "arrives; subscriptions/listen streams are demultiplexed by exactly that id."
         ),
+        note=(
+            f"The demux-by-listen-request-id obligation is the spec's "
+            f"({SPEC_2026_BASE_URL}/basic/patterns/subscriptions#receiving-notifications); supplying the "
+            "id up front is the SDK surface that makes it satisfiable."
+        ),
         added_in="2026-07-28",
         deferred=(
             "No public API surface yet: the capability exists at the dispatcher seam "
@@ -500,8 +505,11 @@ def __post_init__(self) -> None:
         behavior=(
             "Abandoning an in-flight request client-side (cancelling the task awaiting it) cancels the "
             "request itself: the server-side handler stops and the session serves later requests "
-            "normally. Each transport carries the signal in its own spelling - a cancelled frame on "
-            "stream wires, closing the request's own response stream at 2026-07-28 streamable HTTP."
+            "normally."
+        ),
+        note=(
+            "The per-transport wire spelling (frame vs response-stream close) is pinned separately by "
+            "protocol:cancel:stream-frame and the client-transport:http:cancel-* pair."
         ),
         arm_exclusions=(
             ArmExclusion(
@@ -580,7 +588,7 @@ def __post_init__(self) -> None:
         ),
     ),
     "protocol:cancel:stream-frame": Requirement(
-        source=f"{SPEC_2026_BASE_URL}/basic/utilities/cancellation#transport-specific-cancellation",
+        source=f"{SPEC_2026_BASE_URL}/basic/patterns/cancellation#transport-specific-cancellation",
         behavior=(
             "On stream (stdio-shaped) wires at 2026-07-28, abandoning an in-flight request sends exactly "
             "one notifications/cancelled naming its request id - streams keep the frame spelling of "

tests/interaction/lowlevel/test_cancellation.py

@@ -397,7 +397,7 @@ async def call_and_abandon() -> None:
         # dropped while the client is still open, so teardown never races its delivery.
         await anyio.wait_all_tasks_blocked()
         result = await client.call_tool("echo", {})
-        assert result.content == [TextContent(text="ok")]
+        assert result == snapshot(CallToolResult(content=[TextContent(text="ok")]))
 
 
 @requirement("protocol:cancel:abort-scoped")

tests/interaction/transports/test_client_transport_http.py

@@ -307,8 +307,8 @@ async def call_and_abandon() -> None:
             result = await client.call_tool("echo", {})
             assert result.content == [TextContent(text="ok")]
 
-    methods = [json.loads(body)["method"] for method, body in requests if method == "POST"]
-    assert methods == snapshot(["tools/list", "tools/call", "tools/call"])
+    wire = [(method, json.loads(body)["method"] if body else None) for method, body in requests]
+    assert wire == snapshot([("POST", "tools/list"), ("POST", "tools/call"), ("POST", "tools/call")])
 
 
 @requirement("client-transport:http:cancel-posts-frame")