Explicitly add 1Password as SSH agent tested for interoperability.

protocols/sftp/index.md

@@ -126,18 +126,23 @@ The setting is not available in the version installed from the Mac App Store. Re
 
 The agent `ssh-agent` is running by default on macOS. You add private key identities to the authentication agent using the program `ssh-add`. The SSH agent is located using the `IdentityAgent` directive in `~/.ssh/config` or if missing from the environment variable `SSH_AUTH_SOCK`.
 
+The following agents are supported:
+ * OpenSSH `ssh-agent.
+ * [1Password SSH agent](https://developer.1password.com/docs/ssh/agent/compatibility/#cyberduck)
+
 :::
 :::{group-tab} Windows
 
 The following agents are supported:
  * [Pageant](https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html). Refer to [How To Use Pageant to Streamline SSH Key Authentication with PuTTY](https://www.digitalocean.com/community/tutorials/how-to-use-pageant-to-streamline-ssh-key-authentication-with-putty).
  * OpenSSH for Windows using the pipe (`\\.\pipe\openssh-ssh-agent`) by default. Use `IdentityAgent` to set a custom socket path for any other compatible agent if needed. 
+ * [1Password SSH agent](https://developer.1password.com/docs/ssh/agent/compatibility/#cyberduck)
 
 :::
 ::::
 
 :::{tip}
-When authenticating using Public Key Authentication with an SSH agent containing multiple identities, it makes sense to add `IdentitiesOnly yes` in `~/.ssh/config` to limit authentication attempts with this identity only. Otherwise, the server may deny the connection because of too many login failures, and you will receive the error _Too many authentication failures_.
+When authenticating using Public Key Authentication with an SSH agent containing multiple identities, add `IdentitiesOnly yes` in `~/.ssh/config` to limit authentication attempts with this identity only. Otherwise, the server may deny the connection because of too many login failures, and you will receive the error _Too many authentication failures_.
 :::
 
 Since the private key is not always available on the filesystem, specifying a public key as `IdentifyFile` is also supported. This can be used to authenticate using an SSH agent backed by a hardware token containing the private key for example.