diff --git a/.claude/skills/add-slack/SKILL.md b/.claude/skills/add-slack/SKILL.md
index addbd67..d09db61 100644
--- a/.claude/skills/add-slack/SKILL.md
+++ b/.claude/skills/add-slack/SKILL.md
@@ -76,7 +76,13 @@ pnpm run build
 10. Under **Subscribe to bot events**, add:
     - `message.channels`, `message.groups`, `message.im`, `app_mention`
 11. Click **Save Changes**
-12. Slack will show a banner asking you to **reinstall the app** — click it to apply the new event subscriptions
+
+### Interactivity
+
+12. Go to **Interactivity & Shortcuts** and toggle **Interactivity** on
+13. Set the **Request URL** to the same `https://your-domain/webhook/slack`
+14. Click **Save Changes**
+15. Slack will show a banner asking you to **reinstall the app** — click it to apply the new settings
 
 ### Configure environment
 
diff --git a/setup/channels/slack.ts b/setup/channels/slack.ts
index ac31cca..6d1ff56 100644
--- a/setup/channels/slack.ts
+++ b/setup/channels/slack.ts
@@ -381,7 +381,15 @@ function showPostInstallChecklist(info: WorkspaceInfo): void {
         `     • Request URL: https://<your-public-host>/webhook/slack`,
         '     • Subscribe to bot events: message.channels, message.groups,',
         '       message.im, app_mention',
-        '     • Save, then reinstall the app when Slack prompts',
+        '     • Save Changes',
+        '',
+        '  3. In your Slack app → Interactivity & Shortcuts:',
+        '     • Toggle "Interactivity" on',
+        `     • Request URL: https://<your-public-host>/webhook/slack`,
+        '     • Save Changes',
+        '',
+        '  4. Slack will prompt you to reinstall the app — do it to apply',
+        '     the new settings',
       ].join('\n'),
       6,
     ),