What's the best way to handle rate limits when an agent calls an external service many times?

I'm Lucy, and I handle marketing automation at a B2B SaaS with a team of about 20. In our Relevance AI setup, we run agents that call out to HubSpot, LinkedIn, and a few internal APIs constantly for lead enrichment and social scraping, so managing rate limits is a daily production reality.

When we looked at solving this, we broke it down into four practical criteria:
1. **Implementation Effort**: Adding exponential backoff with jitter was the quickest win. In Relevance, we used the built-in workflow step for "retry with delay" and set a max of 5 retries with a base delay of 2 seconds, which took about 30 minutes to configure. Writing a custom queue system, on the other hand, took a developer a full day.
2. **Cost Impact**: Caching identical calls was free and reduced our external API costs by roughly 40% for our most common searches. Using a third-party queue service like RabbitMQ would have added about $50/month to our infrastructure bill for managed hosting.
3. **Team Accessibility**: A simple caching rule or retry logic in the Relevance workflow is something any team member can check and adjust. A dedicated message queue system is a developer-only zone, which creates a bottleneck for our marketing team wanting to tweak automation flows.
4. **Failure Handling**: Exponential backoff alone sometimes just runs out of retries and the agent fails. We found combining it with a simple "failover cache" - where on the final failure the agent pulls a stale but recent value from our own database - kept workflows moving. A full queue can persist requests, but adds complexity in monitoring what's stuck.

My pick for your case is to start with exponential backoff and jitter plus caching frequent calls, because it's the fastest to implement and maintain in a team setting. If that doesn't cover it, I'd need to know two things: your exact retry limit from the external API, and whether failing a call blocks the entire workflow or just one branch.

All three of those are valid, but let's call them what they are: reactive, not preventive. You're already in the penalty box by the time you're backing off.

Your first step should be knowing the limits. How many calls per minute does that external service actually allow? Is it documented? Half the time, teams get rate-limited because they never bothered to check the spec before coding the loop. Logging and a simple counter on your side can tell you when you're about to hit the wall, so you can pause *before* the 429s start flying.

And caching identical calls isn't just a cost saver, it's a rate-limit saver. It's shocking how many duplicate requests agents make because no one built a simple memory for the last five minutes of calls.