fix(reply): require trusted route thread sources

steipete · steipete · commit 52a6b67c592d · 2026-06-01T04:29:02.000+01:00
diff --git a/src/auto-reply/reply/effective-reply-route.test.ts b/src/auto-reply/reply/effective-reply-route.test.ts
@@ -163,6 +163,40 @@ describe("resolveEffectiveReplyRoute", () => {
     });
   });
 
+  it("drops inherited thread ids from unmarked normalized route metadata", () => {
+    expect(
+      resolveEffectiveReplyRoute({
+        ctx: ctx({
+          Provider: "webchat",
+          Surface: "webchat",
+          InputProvenance: {
+            kind: "inter_session",
+            sourceTool: "sessions_send",
+          },
+        }),
+        entry: entry({
+          route: {
+            channel: "feishu",
+            accountId: "work",
+            target: { to: "user:ou_123" },
+            thread: { id: "thread:stale" },
+          },
+          deliveryContext: {
+            channel: "feishu",
+            to: "user:ou_123",
+            accountId: "work",
+            threadId: "thread:stale",
+          },
+        }),
+      }),
+    ).toEqual({
+      channel: "feishu",
+      to: "user:ou_123",
+      accountId: "work",
+      inheritedExternalRoute: true,
+    });
+  });
+
   it("keeps plugin-owned external routes for runtime routability checks", () => {
     expect(
       resolveEffectiveReplyRoute({
diff --git a/src/auto-reply/reply/effective-reply-route.ts b/src/auto-reply/reply/effective-reply-route.ts
@@ -43,7 +43,9 @@ function resolveTrustedInheritedThreadId(
   const routeThread = entry?.route?.thread;
   if (
     routeThread?.id != null &&
-    routeThread.source !== "session" &&
+    (routeThread.source === "explicit" ||
+      routeThread.source === "target" ||
+      routeThread.source === "turn") &&
     stringifyRouteThreadId(routeThread.id) === stringifyRouteThreadId(deliveryThreadId)
   ) {
     return deliveryThreadId;
