Tool-request prompts fail closed on installability

TOOL_REQUESTED now carries the registry's verdict (installable/version/summary).
GUI offers Install only when the event says a pinned build exists.

surfaces/gui/e2e/fixtures.ts

@@ -610,6 +610,16 @@ export async function mockApi(page: import("@playwright/test").Page) {
           });
           return; // suspended on the approval
         }
+        // The pre-fix payload shape (owner-hit 2026-08-14): no installable/version/summary
+        // — an older sidecar, or any surface that forgets the field. Must render NOT
+        // installable, never a guessed Install offer.
+        if (/request an unpinned tool/i.test(msg.text)) {
+          send("tool_requested", {
+            name: "somescanner",
+            reason: "scan the Terraform for misconfigurations",
+          });
+          return; // suspended on the tool request
+        }
         // OPE-85: the agent hits a missing scanner and asks instead of skipping the check.
         if (/scan for secrets/i.test(msg.text)) {
           send("tool_requested", {

surfaces/gui/e2e/toolreq.spec.ts

@@ -23,6 +23,21 @@ test("request_tool surfaces a card naming the tool, the reason and the pinned ve
   await expect(card.getByTestId("toolreq-skip")).toBeVisible();
 });
 
+test("an event without install metadata fails CLOSED — Install disabled, skip offered", async ({
+  page,
+}) => {
+  // Owner-hit 2026-08-14: the card offered "pinned build, checksum-verified" for a tool
+  // with no pinned build; approval could only produce an error. Absence of metadata is NO.
+  await page.goto("/");
+  await page.getByPlaceholder(/Ask the coworker/).fill("request an unpinned tool");
+  await page.getByRole("button", { name: "Send" }).click();
+  const card = page.locator(".dirreq-card");
+  await expect(card).toContainText("somescanner");
+  await expect(card).toContainText(/no verified build/i);
+  await expect(card.getByTestId("toolreq-install")).toBeDisabled();
+  await expect(card.getByTestId("toolreq-skip")).toBeEnabled();
+});
+
 test("installing runs the check; skipping still reports coverage", async ({ page }) => {
   await ask(page);
   await page.getByTestId("toolreq-install").click();

surfaces/gui/src/App.tsx

@@ -737,7 +737,8 @@ export function App() {
               kind: "toolreq",
               tool: d.name || "",
               reason: d.reason || "",
-              installable: d.installable !== false,
+              // Fail CLOSED: only offer Install when the event says a pinned build exists.
+              installable: d.installable === true,
               version: d.version || "",
               summary: d.summary || "",
             },