feat: enforce final tag parsing for embedded PI

src/agents/pi-embedded-subscribe.test.ts

@@ -0,0 +1,95 @@
+import { describe, expect, it, vi } from "vitest";
+import { subscribeEmbeddedPiSession } from "./pi-embedded-subscribe.js";
+
+type StubSession = {
+  subscribe: (fn: (evt: unknown) => void) => () => void;
+};
+
+describe("subscribeEmbeddedPiSession", () => {
+  it("filters to <final> and falls back when tags are malformed", () => {
+    let handler: ((evt: unknown) => void) | undefined;
+    const session: StubSession = {
+      subscribe: (fn) => {
+        handler = fn;
+        return () => {};
+      },
+    };
+
+    const onPartialReply = vi.fn();
+    const onAgentEvent = vi.fn();
+
+    subscribeEmbeddedPiSession({
+      session: session as unknown as Parameters<
+        typeof subscribeEmbeddedPiSession
+      >[0]["session"],
+      runId: "run",
+      enforceFinalTag: true,
+      onPartialReply,
+      onAgentEvent,
+    });
+
+    handler?.({
+      type: "message_update",
+      message: { role: "assistant" },
+      assistantMessageEvent: {
+        type: "text_delta",
+        delta: "<final>Hi there</final>",
+      },
+    });
+
+    expect(onPartialReply).toHaveBeenCalled();
+    const firstPayload = onPartialReply.mock.calls[0][0];
+    expect(firstPayload.text).toBe("Hi there");
+
+    onPartialReply.mockReset();
+
+    handler?.({
+      type: "message_end",
+      message: { role: "assistant" },
+    });
+
+    handler?.({
+      type: "message_update",
+      message: { role: "assistant" },
+      assistantMessageEvent: {
+        type: "text_delta",
+        delta: "</final>Oops no start",
+      },
+    });
+
+    const secondPayload = onPartialReply.mock.calls[0][0];
+    expect(secondPayload.text).toContain("Oops no start");
+  });
+
+  it("does not require <final> when enforcement is off", () => {
+    let handler: ((evt: unknown) => void) | undefined;
+    const session: StubSession = {
+      subscribe: (fn) => {
+        handler = fn;
+        return () => {};
+      },
+    };
+
+    const onPartialReply = vi.fn();
+
+    subscribeEmbeddedPiSession({
+      session: session as unknown as Parameters<
+        typeof subscribeEmbeddedPiSession
+      >[0]["session"],
+      runId: "run",
+      onPartialReply,
+    });
+
+    handler?.({
+      type: "message_update",
+      message: { role: "assistant" },
+      assistantMessageEvent: {
+        type: "text_delta",
+        delta: "Hello world",
+      },
+    });
+
+    const payload = onPartialReply.mock.calls[0][0];
+    expect(payload.text).toBe("Hello world");
+  });
+});