diff --git a/src/agents/pi-extensions/compaction-safeguard.test.ts b/src/agents/pi-extensions/compaction-safeguard.test.ts
index 1394f265f91..8f8e022f9de 100644
--- a/src/agents/pi-extensions/compaction-safeguard.test.ts
+++ b/src/agents/pi-extensions/compaction-safeguard.test.ts
@@ -546,6 +546,19 @@ describe("compaction-safeguard recent-turn preservation", () => {
     expect(section).toContain("[non-text content: image]");
   });
 
+  it("does not add non-text placeholders for text-only content blocks", () => {
+    const section = formatPreservedTurnsSection([
+      {
+        role: "assistant",
+        content: [{ type: "text", text: "plain text reply" }],
+        timestamp: 1,
+      } as unknown as AgentMessage,
+    ]);
+
+    expect(section).toContain("- Assistant: plain text reply");
+    expect(section).not.toContain("[non-text content]");
+  });
+
   it("clamps preserve count into a safe range", () => {
     expect(resolveRecentTurnsPreserve(undefined)).toBe(3);
     expect(resolveRecentTurnsPreserve(-1)).toBe(0);
diff --git a/src/agents/pi-extensions/compaction-safeguard.ts b/src/agents/pi-extensions/compaction-safeguard.ts
index 17714beed55..f54de615463 100644
--- a/src/agents/pi-extensions/compaction-safeguard.ts
+++ b/src/agents/pi-extensions/compaction-safeguard.ts
@@ -220,7 +220,7 @@ function formatNonTextPlaceholder(content: unknown): string | null {
     typeCounts.set(type, (typeCounts.get(type) ?? 0) + 1);
   }
   if (typeCounts.size === 0) {
-    return "[non-text content]";
+    return null;
   }
   const parts = [...typeCounts.entries()].map(([type, count]) =>
     count > 1 ? `${type} x${count}` : type,