Start with X’s own reply control
You do not need an extension to set permissions for a single post. In X’s composer, look below the text area for the reply-audience label. On a fresh post it may say “Everyone can reply.” Open it, pick an available audience, and check the updated label before publishing.
The exact wording depends on your X language and account. A Chinese X page will keep its Chinese labels even if an installed extension has an English interface.
Match the setting to the conversation
Reply Defaults for X offers five saved preferences that correspond to native choices when they are available in X:
- Everyone: for an open conversation.
- Accounts you follow: for replies from the accounts you have chosen to follow.
- Accounts you follow and who they follow: the wider following-network option. This does not mean “accounts you follow and your followers.”
- Only accounts you mention: the mentioned-accounts setting for a narrower conversation.
- Verified accounts: X’s verified-accounts option. Verification is not a guarantee that a reply is trustworthy or free of spam.
X controls which choices are available and how they work. The extension cannot add permissions that your account does not have. In some restricted settings, accounts you mention can still reply.
Can you change it after posting?
X documents a “Change who can reply” action in a published post’s more menu. Use that native action for an existing post. Reply Defaults for X does not bulk-edit previously published posts.
For the current native rules and exceptions, see X Help: About conversations on X ↗. X can change its controls independently of the extension.
Want to stop repeating the same choice?
That is the extension’s job: remember one preferred audience and apply it once to each eligible new blank composer. It uses the same X controls you would use manually, without posting for you.
This distinction matters. A saved default is a starting point for a new post, not a permanent account-wide rule or a way to override X’s permissions. Keep checking the visible audience before publishing, especially after X changes its interface.