fix(slack): pass recipient_team_id and recipient_user_id to chat.startStream

Rahul Subramaniam · claude · Rahul Subramaniam · commit 3b69a0c1580e · 2026-02-19T10:29:43.000+05:30
Slack's streaming API (chat.startStream) requires recipient_team_id and
recipient_user_id when streaming outside of DMs. Without these parameters,
the API returns a missing_recipient_team_id error, causing the stream to
fail entirely and no replies to be delivered.

This adds optional teamId and userId parameters to StartSlackStreamParams
and passes them through to client.chatStream() as recipient_team_id and
recipient_user_id. The call site in dispatch.ts now supplies ctx.teamId
(from auth.test) and message.user.

Co-Authored-By: Claude Opus 4.6 &lt;noreply@anthropic.com&gt;
diff --git a/src/slack/streaming.ts b/src/slack/streaming.ts
@@ -36,6 +36,10 @@ export type StartSlackStreamParams = {
   threadTs: string;
   /** Optional initial markdown text to include in the stream start. */
   text?: string;
+  /** Team ID of the recipient (required for streaming outside DMs). */
+  teamId?: string;
+  /** User ID of the recipient (required for streaming outside DMs). */
+  userId?: string;
 };
 
 export type AppendSlackStreamParams = {
@@ -64,13 +68,15 @@ export type StopSlackStreamParams = {
 export async function startSlackStream(
   params: StartSlackStreamParams,
 ): Promise<SlackStreamSession> {
-  const { client, channel, threadTs, text } = params;
+  const { client, channel, threadTs, text, teamId, userId } = params;
 
   logVerbose(`slack-stream: starting stream in ${channel} thread=${threadTs}`);
 
   const streamer = client.chatStream({
     channel,
     thread_ts: threadTs,
+    ...(teamId ? { recipient_team_id: teamId } : {}),
+    ...(userId ? { recipient_user_id: userId } : {}),
   });
 
   const session: SlackStreamSession = {
