fix(web): restore the read result envelope as a metadata carrier

`McpUiReadResourceResult` — the return type of a registerAppResource read
callback — types `_meta.ui` at the result level, so the envelope is a
supported carrier after all and dropping it lost the hints for servers
using that shape. Consult all three, most-specific first: content item,
result envelope, listing entry; first found wins outright.

Also make the App wiring test wait for BOTH factories by their
advertiseElicitation flag. Waiting on a count passed as soon as either
was built, so stripping the wiring from one call site left the other's
deps in the array and the assertion loop still passed.

Signed-off-by: cliffhall <cliff@futurescale.com>

clients/web/src/App.test.tsx

@@ -3183,15 +3183,26 @@ describe("App MCP App listed-resource metadata wiring (#2055)", () => {
     );
 
     renderWithMantine(<App />);
-    await waitFor(() => expect(appBridgeFactoryDeps.length).toBeGreaterThan(0));
 
-    // Every factory App builds gets the wiring, not just the Apps-tab one.
-    for (const deps of appBridgeFactoryDeps) {
-      expect(deps.getListedResourceMeta?.("ui://weather/app.html")).toEqual(
+    // App builds two factories, differing only in `advertiseElicitation`. Wait
+    // for BOTH by that flag rather than for a count: waiting on "at least one"
+    // would still pass with the wiring stripped from either call site, since
+    // the other's deps sit in the same array.
+    const appsFactory = () =>
+      appBridgeFactoryDeps.find((d) => !d.advertiseElicitation);
+    const elicitationFactory = () =>
+      appBridgeFactoryDeps.find((d) => d.advertiseElicitation === true);
+    await waitFor(() => {
+      expect(appsFactory()).toBeDefined();
+      expect(elicitationFactory()).toBeDefined();
+    });
+
+    for (const deps of [appsFactory(), elicitationFactory()]) {
+      expect(deps?.getListedResourceMeta?.("ui://weather/app.html")).toEqual(
         listedMeta,
       );
       expect(
-        deps.getListedResourceMeta?.("ui://other/app.html"),
+        deps?.getListedResourceMeta?.("ui://other/app.html"),
       ).toBeUndefined();
     }
   });

clients/web/src/components/elements/AppRenderer/createAppBridgeFactory.test.ts

@@ -86,20 +86,24 @@ const fakeClient = { name: "sdk-client" } as unknown as Client;
 /**
  * A UI resource read result. `meta` is the MCP Apps sandbox metadata, which the
  * spec nests under the `_meta` bag's `ui` key — the helper wraps it so every
- * test drives the real wire shape. `opts.flat` writes it to `_meta` unnested
- * instead (the non-conforming shape the host must ignore).
+ * test drives the real wire shape. `opts.at` places the bag on the result
+ * envelope (`McpUiReadResourceResult`) instead of the content item, and
+ * `opts.flat` writes it unnested (the non-conforming shape the host ignores).
  */
 function uiResource(
   text: string | undefined,
   meta?: Record<string, unknown>,
-  opts: { flat?: boolean } = {},
+  opts: { at?: "content" | "result"; flat?: boolean } = {},
 ): ReadResourceResult {
+  const bag = meta ? { _meta: opts.flat ? meta : { ui: meta } } : {};
+  const onResult = opts.at === "result";
   return {
+    ...(onResult ? bag : {}),
     contents: [
       {
         uri: "ui://weather/app.html",
         ...(text === undefined ? {} : { text }),
-        ...(meta ? { _meta: opts.flat ? meta : { ui: meta } } : {}),
+        ...(onResult ? {} : bag),
       },
     ],
   } as ReadResourceResult;
@@ -242,6 +246,67 @@ describe("createAppBridgeFactory", () => {
     });
   });
 
+  it("falls back to the read result's _meta.ui when the content item carries none", async () => {
+    // `McpUiReadResourceResult` — what a registerAppResource callback returns —
+    // types `_meta.ui` at the envelope level, so a server stamping it there
+    // must have it honored.
+    const readResource = vi.fn().mockResolvedValue(
+      uiResource(
+        "<h1>x</h1>",
+        {
+          permissions: { microphone: {} },
+          csp: { connectDomains: ["https://envelope.example.com"] },
+        },
+        { at: "result" },
+      ),
+    );
+    const factory = createAppBridgeFactory({
+      getClient: () => fakeClient,
+      readResource,
+    });
+    await factory(makeIframe(), { kind: "tool", tool });
+    const bridge = bridgeInstances[0];
+    bridge.emit("sandboxready");
+    await flush();
+
+    const call = bridge.sendSandboxResourceReady.mock.calls[0][0] as {
+      html: string;
+      permissions: unknown;
+    };
+    expect(call.permissions).toEqual({ microphone: {} });
+    expect(call.html).toContain("connect-src https://envelope.example.com");
+  });
+
+  it("prefers the read result's _meta.ui over the listing entry's", async () => {
+    // Precedence runs most-specific first: content item, then the result
+    // envelope, then the listing default.
+    const readResource = vi
+      .fn()
+      .mockResolvedValue(
+        uiResource(
+          "<h1>x</h1>",
+          { csp: { connectDomains: ["https://envelope.example.com"] } },
+          { at: "result" },
+        ),
+      );
+    const factory = createAppBridgeFactory({
+      getClient: () => fakeClient,
+      readResource,
+      getListedResourceMeta: () =>
+        listedMeta({ csp: { connectDomains: ["https://listed.example.com"] } }),
+    });
+    await factory(makeIframe(), { kind: "tool", tool });
+    const bridge = bridgeInstances[0];
+    bridge.emit("sandboxready");
+    await flush();
+
+    const call = bridge.sendSandboxResourceReady.mock.calls[0][0] as {
+      html: string;
+    };
+    expect(call.html).toContain("connect-src https://envelope.example.com");
+    expect(call.html).not.toContain("listed.example.com");
+  });
+
   it("falls back to the resources/list entry's _meta.ui when the content block carries none", async () => {
     // ext-apps documents the listing-level `_meta.ui` as the static default for
     // a UI resource, so an app declaring its CSP only there must still have it

clients/web/src/components/elements/AppRenderer/createAppBridgeFactory.ts

@@ -131,11 +131,18 @@ function uiMeta(meta: object | undefined): McpUiResourceMeta | undefined {
 /**
  * First text content block of a UI resource, plus its `_meta.ui` sandbox hints.
  *
- * `listedMeta` is the `_meta` of the matching `resources/list` entry, which
- * ext-apps documents as the static default a host can review at connection
- * time; a `resources/read` content item carrying its own `_meta.ui` takes
- * precedence over it (`McpUiAppResourceConfig`). Nothing else is consulted —
- * in particular the read RESULT's own `_meta` is not a documented carrier.
+ * ext-apps exposes three carriers, and they are consulted most-specific first:
+ *
+ * 1. the **read content item**'s own `_meta.ui`;
+ * 2. the **read result envelope**'s — `McpUiReadResourceResult` (what a
+ *    `registerAppResource` callback returns) types `_meta.ui` at that level;
+ * 3. the matching **`resources/list` entry**'s, which `McpUiAppResourceConfig`
+ *    documents as the static default a host reviews at connection time, and
+ *    which a read content item explicitly takes precedence over.
+ *
+ * Whichever is found first wins outright — the levels are not merged, since a
+ * server that restates only `csp` at the more specific level means that to be
+ * the whole grant, not a patch over the broader one.
  */
 function extractHtmlAndMeta(
   result: ReadResourceResult,
@@ -149,7 +156,8 @@ function extractHtmlAndMeta(
     if (typeof text === "string") {
       return {
         html: text,
-        meta: uiMeta(content._meta) ?? uiMeta(listedMeta),
+        meta:
+          uiMeta(content._meta) ?? uiMeta(result._meta) ?? uiMeta(listedMeta),
       };
     }
   }