test(conformance): arm the fixture for the sep-2575 list_changed-on-listen SHOULD checks

test/conformance/expected-failures.2026-07-28.yaml

@@ -67,10 +67,6 @@ client:
 
 server:
     # --- Carried-forward scenarios (also run by the 2025 legs) ---
-    # WARNING-only: see the matching entry in expected-failures.yaml — the
-    # sep-2575 list_changed-on-listen SHOULD checks; fixture armed in a
-    # follow-up change.
-    - server-stateless
     # Pre-existing fixture/baseline bug: the fixture tool's schema is a plain
     # Zod object with none of the JSON Schema 2020-12 keywords the scenario
     # checks; it fails identically at 2025 in `--suite all` (not a 2026-path

test/conformance/expected-failures.yaml

@@ -49,14 +49,6 @@ client:
 
 server:
     # --- Draft-spec scenarios (in `--suite draft`; the default `active` suite is green) ---
-    # WARNING-only: with the listChanged capability now advertised in
-    # server/discover, server-stateless runs three additional SHOULD-level
-    # checks (sep-2575-server-sends-{tools,prompts,resources}-list-changed-on-
-    # subscription) that the conformance fixture cannot yet satisfy because it
-    # is not wired to publish list_changed events to listen streams. The
-    # fixture is armed in a follow-up change, after which this entry burns
-    # down.
-    - server-stateless
     # SEP-2243 (HTTP header standardization): the reject cells the SDK does
     # answer now use -32001 (HeaderMismatch), but missing-header enforcement
     # (Mcp-Method, Mcp-Name) and the Mcp-Name cross-check are not implemented,

test/conformance/src/everythingServer.ts

@@ -967,6 +967,43 @@ function createMcpServer() {
         }
     );
 
+    // ===== SUBSCRIPTION/LISTEN DIAGNOSTIC TRIGGERS (SEP-2575) =====
+    //
+    // The `server-stateless` conformance scenario opens a `subscriptions/listen`
+    // stream (served by `createMcpHandler`'s built-in listen router), then calls
+    // one of these triggers and asserts the corresponding `*/list_changed`
+    // notification arrives on the open stream. The trigger publishes the change
+    // event onto the handler's bus via the `handler.notify.*` sugar — the
+    // listen router stamps the subscription id and applies the per-stream
+    // filter, so the same trigger also exercises the ack-first and
+    // honors-notification-filter checks. The 2026-07-28 path is per-request
+    // (each call gets a fresh `McpServer`), so there is no list to mutate; the
+    // event itself is what the SHOULD requirement measures.
+
+    mcpServer.registerTool(
+        'test_trigger_tool_change',
+        {
+            description: 'Listen diagnostic (SEP-2575): publishes a tools/list_changed event onto the handler bus',
+            inputSchema: z.object({})
+        },
+        async (): Promise<CallToolResult> => {
+            modernHandler.notify.toolsChanged();
+            return { content: [{ type: 'text', text: 'tools_list_changed published' }] };
+        }
+    );
+
+    mcpServer.registerTool(
+        'test_trigger_prompt_change',
+        {
+            description: 'Listen diagnostic (SEP-2575): publishes a prompts/list_changed event onto the handler bus',
+            inputSchema: z.object({})
+        },
+        async (): Promise<CallToolResult> => {
+            modernHandler.notify.promptsChanged();
+            return { content: [{ type: 'text', text: 'prompts_list_changed published' }] };
+        }
+    );
+
     // ===== RESOURCES =====
 
     // Static text resource