diff --git a/components/artifacts/steer-card.tsx b/components/artifacts/steer-card.tsx
index d1b223d..fab2503 100644
--- a/components/artifacts/steer-card.tsx
+++ b/components/artifacts/steer-card.tsx
@@ -15,11 +15,11 @@ import { VisualOutputCard } from "@/components/artifacts/visual-card";
  * ("data-subagent-artifact") carries the result. It renders as an artifact —
  * NEVER a learner bubble, never wrapped in a message container:
  *
- *   research — a quiet "Research complete" badge. The full brief is TOO LONG
- *     to inline and the teacher's wake turn weaves it into the lesson anyway;
- *     it stays persisted in the transcript (the artifact part), so a
- *     "view full research" affordance can be added later. Failures keep the
- *     failure card (the brief explains what went wrong).
+ *   research — a quiet "Research complete" one-liner that expands on demand
+ *     (native <details>) to the full persisted brief + sources: the brief is
+ *     too long to inline by default and the teacher's wake turn weaves it
+ *     into the lesson anyway. Failures keep the failure card (the brief
+ *     explains what went wrong).
  *   demo / visual — the artifact itself (sandboxed iframe / sanitized SVG).
  *     The sub-agent's verification notes are model-facing glue and do NOT
  *     render; only a failure note does.
@@ -48,15 +48,25 @@ export function SubagentSteerCard({ message }: { message: TeacherUIMessage }) {
 	}
 }
 
-/** Quiet one-liner, the dispatch-settled idiom: the brief lives in the record,
- * the lesson lives in the teacher's wake turn — the badge just marks delivery. */
+/** Quiet one-liner, the dispatch-settled idiom — the lesson lives in the
+ * teacher's wake turn; the badge just marks delivery. The persisted brief
+ * rides along in a collapsed <details> (the wave-1 "view full research"
+ * affordance): full markdown + sources, one click away, no extra fetch —
+ * the artifact part in the record is the single source of truth. */
 function ResearchCompleteBadge({ result }: { result: ResearchResult }) {
 	return (
-		<div className="flex items-center gap-2 text-xs text-muted-foreground" data-testid="research-complete-badge">
-			<CheckIcon className="size-3.5" />
-			<span className="font-medium uppercase tracking-wide">Research</span>
-			<span>complete</span>
-			{result.sources.length > 0 && <span>· {result.sources.length} sources</span>}
-		</div>
+		<details data-testid="research-complete-badge" className="group w-full text-xs text-muted-foreground">
+			<summary className="flex cursor-pointer select-none list-none items-center gap-2 [&::-webkit-details-marker]:hidden">
+				<CheckIcon className="size-3.5" />
+				<span className="font-medium uppercase tracking-wide">Research</span>
+				<span>complete</span>
+				{result.sources.length > 0 && <span>· {result.sources.length} sources</span>}
+				<span className="ml-1 text-[11px] text-muted-foreground/70 group-open:hidden">view brief</span>
+				<span className="ml-1 hidden text-[11px] text-muted-foreground/70 group-open:inline">hide brief</span>
+			</summary>
+			<div className="mt-2">
+				<ResearchBriefCard output={result} />
+			</div>
+		</details>
 	);
 }
diff --git a/tests/demos.test.tsx b/tests/demos.test.tsx
index b2b349c..84c151b 100644
--- a/tests/demos.test.tsx
+++ b/tests/demos.test.tsx
@@ -342,7 +342,7 @@ describe("steer card rendering (the delivered artifact)", () => {
 		assert.ok(!html.includes("Looking at the render"), "model-facing notes never render");
 	});
 
-	it("renders a quiet Research-complete badge — the full brief stays out of the transcript (but persisted)", () => {
+	it("renders a quiet Research-complete one-liner whose collapsed <details> carries the full brief", () => {
 		const steer = buildSubagentSteer(
 			{ id: "jr", kind: "research", toolCallId: "cr" },
 			{
@@ -357,8 +357,14 @@ describe("steer card rendering (the delivered artifact)", () => {
 		assert.match(html, /Research/);
 		assert.match(html, /complete/);
 		assert.match(html, /2 sources/);
-		assert.ok(!html.includes("founded the Academy"), "the long brief never renders inline");
-		assert.ok(!html.includes("britannica"), "source links stay out too — the wake turn cites them");
+		assert.match(html, /view brief/, "the expansion affordance is offered");
+		// the one-liner is a native <details> — collapsed by default, so the
+		// brief + sources ride in the DOM but never clutter the transcript
+		// until the learner opens them (the wave-1 "view full research" ask)
+		assert.match(html, /<details[^>]*data-testid="research-complete-badge"/, "a real disclosure");
+		assert.ok(!/<details[^>]*open/.test(html), "collapsed by default — no `open` attribute");
+		assert.ok(html.includes("founded the Academy"), "the persisted brief rides inside the details");
+		assert.ok(html.includes("britannica.com/plato"), "source links ride inside the details");
 	});
 
 	it("renders the visual failure note with no svg when the build FAILED", () => {