The initial issue was the OpenAI API key, and then realizing that I can't switch to a Tier 1 API key that I control, I had to ask a different team for their API key.
Once I got the API loaded again, I had to change the prompt. Which surprised me, because the prompt worked on the first 2,000 leads? It doesn't make sense for the prompt to have changed just because the API ran out of credits, but I'm trying not to look a gift horse in the mouth.
I removed this from the prompt:
**MANDATORY:** The very first logged action must always be: `Visited website {profile_url}`. No searches, lookups, or secondary actions may precede this. After visiting the URL and extracting profile details, perform any necessary secondary queries to validate company-domain relationships, related entities, or ambiguities.