Free LLM Tiers Are Lying to You — Model Rotation Saved My Agent

I built a small autonomous agent (GitHub issue triage) that runs entirely on free LLM tiers — no API budget, no GPU, no AWS account. The project itself is ~250 lines and works. The interesting part is what the free tier did to me.

The 503 wall

The plan was simple: every open issue → LLM → JSON verdict. First real run on a big repo: almost every call failed. Not because the prompt was bad — because the model endpoint answered with 503 Service Unavailable. Free endpoints on popular models are chronically overloaded; they accept the request and then just… don't.

This isn't hypothetical. My scan of facebook/react (22 items) hit 503s repeatedly; the "free" model that the docs told me to use was effectively down half the time.

Free LLM Tiers Are Lying to You — Model Rotation Saved My Agent

Related reading

I Built a Local LLM Rig to Escape API Bills. Then I Paid OpenAI Again.

I Cut My LLM Bill 40x Without Rewriting a Single Line

I Built an Adversarial Eval Framework and Attacked 5 LLMs — Every Single One…

How I Cut My LLM Costs by 90% Without Changing My App Logic

Zero-Budget Release Notes: A Case Study in Free-Tier LLM Automation

I Cut My LLM Bill 40x: A Backend Engineer's Migration Notes