Your contacts come in from different places: an ad, a website form, a free trial, an import. A source name like "Trial Start" means something to you, but not much to the AI. The Lead Sources page lets you explain each source in plain words, so the texts the AI writes for a contact know how that person came in.
Who can use it
Account owners and admins. Other teammates can't change lead sources.
Find the page
Open Settings.
Under Leads & CRM, choose Lead Sources (next to Custom Fields).
You'll see every source your contacts have come from, busiest first, with how many new contacts each brought in over the last 30 days. New sources are added on their own as leads arrive.
Describe a source
Click Edit on a source.
In What it means, write how a contact from this source found you. For example: "Started a free trial on our website."
Check the preview. It shows exactly what the AI will be told, starting with "How they came in:".
Click Save.
Let the AI use it
Every source starts with the AI switched off, so nothing changes until you choose. Turn on Let the AI use this source for any source you've described. From then on, AI texts to contacts from that source reflect your description.
You need to write a meaning before you can switch the AI on. Turn the switch off any time and the AI stops using it.
Good to know
If a contact came in from more than one source, the AI uses the most recent one you've described.
Sources with the AI off, or with no meaning written, don't change anything the AI writes.