diff --git a/frontend/src/widgets/ArtifactGateWidget.test.tsx b/frontend/src/widgets/ArtifactGateWidget.test.tsx
index 1facd7da..7c7eb102 100644
--- a/frontend/src/widgets/ArtifactGateWidget.test.tsx
+++ b/frontend/src/widgets/ArtifactGateWidget.test.tsx
@@ -2,19 +2,25 @@ import { render, screen } from "@testing-library/react";
 import userEvent from "@testing-library/user-event";
 import { ArtifactGateWidget } from "./ArtifactGateWidget";
 
-test("renders artifact content in a pre block", () => {
+vi.mock("../viewers/mermaid", () => ({
+  renderMermaid: vi.fn().mockResolvedValue('<svg data-testid="mm"></svg>'),
+}));
+
+test("renders inside a dialog and shows the artifact via ArtifactView (data path)", () => {
   const onRespond = vi.fn();
   render(
     <ArtifactGateWidget
       descriptor={{
         id: "u1",
         widget: "artifact-gate",
-        artifact: { kind: "cte", content: "SELECT 42" },
+        title: "SQL finale",
+        artifact: { kind: "sql", data: "SELECT 42" },
         options: [{ id: "approve", label: "Approva" }],
       }}
       onRespond={onRespond}
     />
   );
+  expect(screen.getByRole("dialog")).toBeInTheDocument();
   expect(screen.getByText("SELECT 42")).toBeInTheDocument();
 });
 
diff --git a/frontend/src/widgets/ArtifactGateWidget.tsx b/frontend/src/widgets/ArtifactGateWidget.tsx
index 641ac6b0..cd2adff0 100644
--- a/frontend/src/widgets/ArtifactGateWidget.tsx
+++ b/frontend/src/widgets/ArtifactGateWidget.tsx
@@ -1,9 +1,18 @@
 import { useState } from "react";
 import type { WidgetProps } from "./types";
 import type { UiResponse, WidgetDescriptor } from "../api/types";
+import { Dialog, DialogContent, DialogTitle } from "../components/ui/dialog";
+import { ArtifactView } from "../viewers/ArtifactView";
 import { ReservedControls } from "./ReservedControls";
 import { LinkageHost } from "./LinkageHost";
 
+/**
+ * Artifact review gate rendered as a full-screen (90%) modal: the artifact fills
+ * the top (scrollable) area via ArtifactView; the action bar (options + reserved
+ * controls) sits at the bottom. The gate contract forbids silent dismissal, so the
+ * dialog has no close button and is not closeable by Esc/backdrop — the only way
+ * out is an action or a reserved control, both of which call onRespond.
+ */
 export function ArtifactGateWidget({ descriptor, onRespond }: WidgetProps) {
   const [pendingLinkage, setPendingLinkage] = useState<{
     parentResponse: UiResponse;
@@ -13,48 +22,56 @@ export function ArtifactGateWidget({ descriptor, onRespond }: WidgetProps) {
   function handleOption(optionId: string) {
     const option = descriptor.options?.find((o) => o.id === optionId);
     const parentResponse: UiResponse = { id: descriptor.id, kind: "artifact-gate", choices: [optionId] };
-
-    if (option?.opens) {
-      // Route through LinkageHost to collect child text first
-      setPendingLinkage({ parentResponse, childDescriptor: option.opens });
-    } else {
-      onRespond(parentResponse);
-    }
-  }
-
-  if (pendingLinkage) {
-    return (
-      <LinkageHost
-        parentResponse={pendingLinkage.parentResponse}
-        childDescriptor={pendingLinkage.childDescriptor}
-        onRespond={onRespond}
-      />
-    );
+    if (option?.opens) setPendingLinkage({ parentResponse, childDescriptor: option.opens });
+    else onRespond(parentResponse);
   }
 
   return (
-    <div className="space-y-3">
-      {descriptor.title && <p className="font-medium">{descriptor.title}</p>}
-      {descriptor.artifact?.content && (
-        <pre className="overflow-auto max-h-64 bg-muted p-3 text-sm rounded border">
-          {descriptor.artifact.content}
-        </pre>
-      )}
-      <div className="flex flex-col gap-2">
-        {descriptor.options?.map((o) => (
-          <button
-            key={o.id}
-            className="border rounded px-3 py-2 text-left hover:bg-accent"
-            onClick={() => handleOption(o.id)}
-          >
-            {o.label}
-          </button>
-        ))}
-      </div>
-      <ReservedControls
-        reserved={descriptor.reserved}
-        onControl={(c, t) => onRespond({ id: descriptor.id, control: c, ...(t !== undefined ? { text: t } : {}) })}
-      />
-    </div>
+    <Dialog open>
+      <DialogContent
+        showCloseButton={false}
+        className="grid h-[90vh] w-[90vw] max-w-[90vw] grid-rows-[auto_1fr_auto] gap-3 sm:max-w-[90vw]"
+      >
+        <DialogTitle>{descriptor.title ?? "Artifact review"}</DialogTitle>
+
+        <div className="min-h-0 overflow-auto rounded border bg-background p-3">
+          {descriptor.artifact ? (
+            <ArtifactView artifact={descriptor.artifact} />
+          ) : (
+            <p className="text-sm text-muted-foreground">No artifact.</p>
+          )}
+        </div>
+
+        <div className="flex flex-col gap-2 border-t pt-3">
+          {pendingLinkage ? (
+            <LinkageHost
+              parentResponse={pendingLinkage.parentResponse}
+              childDescriptor={pendingLinkage.childDescriptor}
+              onRespond={onRespond}
+            />
+          ) : (
+            <>
+              <div className="flex flex-wrap gap-2">
+                {descriptor.options?.map((o) => (
+                  <button
+                    key={o.id}
+                    className="rounded border px-3 py-2 text-left hover:bg-accent"
+                    onClick={() => handleOption(o.id)}
+                  >
+                    {o.label}
+                  </button>
+                ))}
+              </div>
+              <ReservedControls
+                reserved={descriptor.reserved}
+                onControl={(c, t) =>
+                  onRespond({ id: descriptor.id, control: c, ...(t !== undefined ? { text: t } : {}) })
+                }
+              />
+            </>
+          )}
+        </div>
+      </DialogContent>
+    </Dialog>
   );
 }