fix(slack): prefer current thread session for inherited outbound replies (#97168)

LiuwqGit · Peter Steinberger · web-flow · commit 5e572dcf781a · 2026-06-30T16:38:34.000-07:00
* fix(slack): prefer current thread session for inherited outbound replies to avoid delivery-mirror session sprawl

* fix(slack): require explicit replyToIsExplicit===false for current-session precedence

* fix(slack): canonicalize inherited thread replies

---------

Co-authored-by: Peter Steinberger &lt;steipete@golden-gate.local&gt;
diff --git a/extensions/slack/src/channel.test.ts b/extensions/slack/src/channel.test.ts
@@ -874,6 +874,33 @@ describe("slackPlugin outbound", () => {
     });
   });
 
+  it.each([
+    {
+      name: "inherited",
+      replyToIsExplicit: false,
+      expectedReplyToId: "1712345678.123456",
+    },
+    { name: "explicit", replyToIsExplicit: true, expectedReplyToId: "1712345688.654321" },
+    { name: "unknown", replyToIsExplicit: undefined, expectedReplyToId: "1712345688.654321" },
+  ])(
+    "routes $name child replies to $expectedReplyToId",
+    ({ replyToIsExplicit, expectedReplyToId }) => {
+      const resolveReplyTransport = slackPlugin.threading?.resolveReplyTransport;
+      if (!resolveReplyTransport) {
+        throw new Error("slack threading.resolveReplyTransport unavailable");
+      }
+
+      expect(
+        resolveReplyTransport({
+          cfg,
+          replyToId: "1712345688.654321",
+          threadId: "1712345678.123456",
+          replyToIsExplicit,
+        }),
+      ).toEqual({ replyToId: expectedReplyToId, threadId: null });
+    },
+  );
+
   it("ignores explicit reply targets for off-mode final delivery", () => {
     const resolveReplyTransport = slackPlugin.threading?.resolveReplyTransport;
     if (!resolveReplyTransport) {
diff --git a/extensions/slack/src/channel.ts b/extensions/slack/src/channel.ts
@@ -663,8 +663,7 @@ export const slackPlugin: ChannelPlugin<ResolvedSlackAccount, SlackProbe> = crea
         }
         return resolveTargetsWithOptionalToken({
           token:
-            normalizeOptionalString(account.userToken) ??
-            normalizeOptionalString(account.botToken),
+            normalizeOptionalString(account.userToken) ?? normalizeOptionalString(account.botToken),
           inputs,
           missingTokenNote: "missing Slack token",
           resolveWithToken: async ({ token, inputs: inputsLocal }) =>
@@ -819,10 +818,14 @@ export const slackPlugin: ChannelPlugin<ResolvedSlackAccount, SlackProbe> = crea
               toolContext,
             }),
           ),
-    resolveReplyTransport: ({ threadId, replyToId, replyDelivery }) => {
+    resolveReplyTransport: ({ threadId, replyToId, replyToIsExplicit, replyDelivery }) => {
+      const allowedReplyToId = replyDelivery?.replyToMode === "off" ? undefined : replyToId;
+      // Slack's thread_ts identifies the root. Only known inherited replies may let
+      // that root replace a child timestamp; explicit and unknown callers stay reply-first.
+      const preferThreadId = replyToIsExplicit === false;
       const resolvedReplyToId = resolveSlackThreadTsValue({
-        replyToId: replyDelivery?.replyToMode === "off" ? undefined : replyToId,
-        threadId,
+        replyToId: preferThreadId ? threadId : allowedReplyToId,
+        threadId: preferThreadId ? allowedReplyToId : threadId,
       });
       return {
         replyToId:
