From the automation rules:
Spamming: You may not send automated Tweets or Direct Messages that are spam, or otherwise engage in spamming activity. Some examples of spammy behavior to avoid with automation include:
Trending topics: You may not automatically post about trending topics on Twitter, or use automation to attempt to influence or manipulate trending topics.
Multiple posts/accounts: You may not post duplicative or substantially similar Tweets on one account or over multiple accounts you operate.
There’s no additional guidance that we can provide beyond this.