diff --git a/apps/server/src/orchestration-v2/WireProjection.test.ts b/apps/server/src/orchestration-v2/WireProjection.test.ts
index 6379cad45dbd0..95d3fcde7f401 100644
--- a/apps/server/src/orchestration-v2/WireProjection.test.ts
+++ b/apps/server/src/orchestration-v2/WireProjection.test.ts
@@ -175,7 +175,9 @@ describe("orchestration V2 wire projection", () => {
   });
 
   it("truncates detail at a UTF-8 boundary without changing the source", () => {
-    const progress = "a".repeat(32_767) + "😀" + "x".repeat(100_000);
+    const marker = "\n… output truncated for transport";
+    const prefixBytes = 32_768 - Buffer.byteLength(marker);
+    const progress = "a".repeat(prefixBytes - 1) + "😀" + "x".repeat(100_000);
     const item = {
       ...base,
       type: "subagent" as const,
@@ -184,13 +186,17 @@ describe("orchestration V2 wire projection", () => {
       driver: ProviderDriverKind.make("codex"),
       providerInstanceId: ProviderInstanceId.make("codex"),
       childThreadId: null,
-      prompt: "Inspect code",
+      prompt: "漢".repeat(12_000),
       result: null,
       progress,
     };
     const projected = projectTurnItemForWire(item);
+    expect(projectTurnItemForWire(projected)).toEqual(projected);
+    expect(
+      Buffer.byteLength(projected.type === "subagent" ? projected.prompt : ""),
+    ).toBeLessThanOrEqual(32_768);
     expect(projected.type === "subagent" ? projected.progress : null).toBe(
-      "a".repeat(32_767) + "\n… output truncated for transport",
+      "a".repeat(prefixBytes - 1) + marker,
     );
     expect(item.progress).toBe(progress);
   });
diff --git a/apps/server/src/orchestration-v2/WireProjection.ts b/apps/server/src/orchestration-v2/WireProjection.ts
index 1495a3effa677..c4916546cf8e1 100644
--- a/apps/server/src/orchestration-v2/WireProjection.ts
+++ b/apps/server/src/orchestration-v2/WireProjection.ts
@@ -26,6 +26,8 @@ const MAX_WIRE_CHECKPOINT_FILES = 200;
 const MAX_DETAIL_STRING_BYTES = 32_768;
 const MAX_DYNAMIC_VALUE_BYTES = 16_384;
 const MAX_ON_DEMAND_BYTES = 256 * 1024;
+const TRUNCATION_MARKER = "\n… output truncated for transport";
+const TRUNCATION_MARKER_BYTES = Buffer.byteLength(TRUNCATION_MARKER, "utf8");
 
 function truncateDetail(
   value: string | undefined,
@@ -37,12 +39,14 @@ function truncateDetail(
   ) {
     return value;
   }
+  // The marker counts toward the cap, so projecting truncated text again leaves it unchanged.
+  const budget = maxBytes - TRUNCATION_MARKER_BYTES;
   // UTF-8 needs at least one byte per UTF-16 unit; encode only a potentially fitting prefix.
-  const prefix = Buffer.from(value.slice(0, maxBytes), "utf8")
-    .subarray(0, maxBytes)
+  const prefix = Buffer.from(value.slice(0, budget), "utf8")
+    .subarray(0, budget)
     .toString("utf8")
     .replace(/\uFFFD$/u, "");
-  return `${prefix}\n… output truncated for transport`;
+  return `${prefix}${TRUNCATION_MARKER}`;
 }
 
 /** Bound stored diffs to the client wire limit to avoid retaining invisible data in SQLite and heap. */
diff --git a/apps/server/src/ws.ts b/apps/server/src/ws.ts
index 4781fcf78dde6..9b97c61260580 100644
--- a/apps/server/src/ws.ts
+++ b/apps/server/src/ws.ts
@@ -813,7 +813,7 @@ export const subscribeOrchestrationV2Thread = Effect.fn("ws.orchestrationV2.subs
           Stream.map((stored) => ({
             kind: "event" as const,
             sequence: stored.sequence,
-            event: projectDomainEventForWire(stored.event),
+            event: stored.event,
           })),
           coalesceThreadLiveStream,
           Stream.mapError(