diff --git a/gateway/run.py b/gateway/run.py
index 449e9464..ea768ca6 100644
--- a/gateway/run.py
+++ b/gateway/run.py
@@ -4606,12 +4606,20 @@ class GatewayRunner:
             if not os.getenv(env_key):
                 adapter = self.adapters.get(source.platform)
                 if adapter:
+                    # Slack dispatches all Hermes commands through a single
+                    # parent slash command `/hermes`; bare `/sethome` is not
+                    # registered and would fail with "app did not respond".
+                    sethome_cmd = (
+                        "/hermes sethome"
+                        if source.platform == Platform.SLACK
+                        else "/sethome"
+                    )
                     await adapter.send(
                         source.chat_id,
                         f"📬 No home channel is set for {platform_name.title()}. "
                         f"A home channel is where Hermes delivers cron job results "
                         f"and cross-platform messages.\n\n"
-                        f"Type /sethome to make this chat your home channel, "
+                        f"Type {sethome_cmd} to make this chat your home channel, "
                         f"or ignore to skip."
                     )