diff --git a/extensions/acpx/src/runtime-internals/events.test.ts b/extensions/acpx/src/runtime-internals/events.test.ts
index bb8067c3327..6358cf339ca 100644
--- a/extensions/acpx/src/runtime-internals/events.test.ts
+++ b/extensions/acpx/src/runtime-internals/events.test.ts
@@ -67,6 +67,37 @@ describe("parsePromptEventLine", () => {
     });
   });
 
+  it("parses JSON-RPC result stopReason as done", () => {
+    const line = JSON.stringify({
+      jsonrpc: "2.0",
+      id: 3,
+      result: {
+        stopReason: "end_turn",
+      },
+    });
+    expect(parsePromptEventLine(line)).toEqual({
+      type: "done",
+      stopReason: "end_turn",
+    });
+  });
+
+  it("parses JSON-RPC errors as runtime errors", () => {
+    const line = JSON.stringify({
+      jsonrpc: "2.0",
+      id: 2,
+      error: {
+        code: -32002,
+        message: "Resource not found",
+      },
+    });
+    expect(parsePromptEventLine(line)).toEqual({
+      type: "error",
+      message: "Resource not found",
+      code: undefined,
+      retryable: undefined,
+    });
+  });
+
   it("keeps compatibility with simplified text/done lines", () => {
     expect(parsePromptEventLine(JSON.stringify({ type: "text", content: "alpha" }))).toEqual({
       type: "text_delta",
diff --git a/extensions/acpx/src/runtime-internals/events.ts b/extensions/acpx/src/runtime-internals/events.ts
index f83f4ddabb9..8e863605aba 100644
--- a/extensions/acpx/src/runtime-internals/events.ts
+++ b/extensions/acpx/src/runtime-internals/events.ts
@@ -65,6 +65,28 @@ function resolveStructuredPromptPayload(parsed: Record<string, unknown>): {
     }
   }
 
+  const result = parsed.result;
+  if (isRecord(result)) {
+    const stopReason = asTrimmedString(result.stopReason);
+    if (stopReason) {
+      return {
+        type: "done",
+        payload: result,
+      };
+    }
+  }
+
+  const rpcError = parsed.error;
+  if (isRecord(rpcError)) {
+    const message = asTrimmedString(rpcError.message);
+    if (message) {
+      return {
+        type: "error",
+        payload: rpcError,
+      };
+    }
+  }
+
   const sessionUpdate = asOptionalString(parsed.sessionUpdate) as AcpSessionUpdateTag | undefined;
   if (sessionUpdate) {
     return {