docs(example): note required "Reply to messages" business permission

BUSINESS_PEER_INVALID was the bot lacking message permissions, not a code
issue: enable "Reply to messages" (and others) under Settings → Business →
Chatbots → Chat Automation. Document it in the business example and remove the
temporary peer/connection diagnostics now that the cause is known.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: ernado

business_updates.go

@@ -62,7 +62,6 @@ func (b *Bot) dispatchBusinessMessage(ctx context.Context, e tg.Entities, connec
 	m.BusinessConnectionID = connectionID
 	if m.raw != nil {
 		m.businessPeer = inputPeerFromEntities(m.raw.PeerID, e)
-		b.logBusinessPeerDiag(ctx, m.raw.PeerID, e, m.businessPeer)
 	}
 
 	u := &Update{}
@@ -75,46 +74,6 @@ func (b *Bot) dispatchBusinessMessage(ctx context.Context, e tg.Entities, connec
 	b.route(ctx, u)
 }
 
-// logBusinessPeerDiag logs how a business message's send peer was (or was not)
-// resolved, to diagnose BUSINESS_PEER_INVALID: whether the peer was present in
-// the update's entities, and the access hash / min flag carried there.
-func (b *Bot) logBusinessPeerDiag(ctx context.Context, peer tg.PeerClass, e tg.Entities, resolved tg.InputPeerClass) {
-	fields := []log.Attr{
-		log.String("raw_peer", peerKindString(peer)),
-		log.Bool("resolved_from_entities", resolved != nil),
-		log.Int("entity_users", len(e.Users)),
-		log.Int("entity_chats", len(e.Chats)),
-		log.Int("entity_channels", len(e.Channels)),
-	}
-
-	if pu, ok := peer.(*tg.PeerUser); ok {
-		if u, ok := e.Users[pu.UserID]; ok {
-			fields = append(fields,
-				log.Int64("entity_access_hash", u.AccessHash),
-				log.Bool("entity_min", u.Min),
-			)
-		} else {
-			fields = append(fields, log.Bool("user_in_entities", false))
-		}
-	}
-
-	b.logger().Debug(ctx, "Business peer diagnostic", fields...)
-}
-
-// peerKindString describes a peer for diagnostics.
-func peerKindString(peer tg.PeerClass) string {
-	switch peer.(type) {
-	case *tg.PeerUser:
-		return peerKindUser
-	case *tg.PeerChat:
-		return peerKindChat
-	case *tg.PeerChannel:
-		return peerKindChannel
-	default:
-		return "none"
-	}
-}
-
 // inputPeerFromEntities builds the input peer for a message's chat from the
 // access hashes delivered with the update, so a business send addresses the chat
 // with the account's own access hash. Returns nil when the peer is absent.

examples/business/main.go

@@ -11,6 +11,11 @@
 //     this bot. That delivers the account's 1-to-1 chats to the bot over a
 //     business connection.
 //
+//     IMPORTANT: under "Chat Automation", enable "Reply to messages" (and the
+//     other permissions you want the bot to use — manage profile, gifts, …).
+//     Without the reply permission, sending on behalf of the account fails with
+//     400 BUSINESS_PEER_INVALID even though everything else is correct.
+//
 //  3. From another account, write to the business account. Plain text is echoed
 //     back (as the account). Messages starting with "!" are commands:
 //
@@ -137,23 +142,6 @@ func handleBusiness(log *zap.Logger) botapi.Handler {
 			return nil
 		}
 
-		// Diagnostic: fetch the connection (a read, never a business send) to see
-		// the owner id and granted rights, and whether we are about to reply to
-		// the owner themselves (an invalid business peer).
-		if conn, err := bc.Connection(c); err == nil {
-			canReply := conn.Rights != nil && conn.Rights.CanReply
-			log.Info("Business connection state",
-				zap.String("connection", conn.ID),
-				zap.Int64("owner_id", conn.User.ID),
-				zap.Bool("enabled", conn.IsEnabled),
-				zap.Bool("can_reply", canReply),
-				zap.Int64("reply_peer", bm.Chat.ID),
-				zap.Bool("reply_peer_is_owner", conn.User.ID == bm.Chat.ID),
-			)
-		} else {
-			log.Warn("Get business connection", zap.Error(err))
-		}
-
 		log.Info("Business message",
 			zap.String("connection", bc.ConnectionID()),
 			zap.Int64("chat", bm.Chat.ID),