The problem with "free" AI APIs for agents

Most AI APIs want an account, an API key, and a billing relationship before you can call them. That works for a human with a credit card. It does not work for an autonomous agent that needs to pay for a single summarization and move on.

There is a standard for exactly this: HTTP 402 Payment Required . The server refuses the request, tells you what it costs and where to pay, you pay, and you retry with proof. No signup, no dashboard, no approval queue.

I built Hermes Micro-Agent on that model. This is what it looks like from the outside.

What it does

Twenty tasks across four categories, each priced per call in USDC on Base:

Category Tasks Price

Text summarize, extract, keywords, sentiment, translate, rewrite, proofread $0.10

Code python_debug, code_lint, code_explain, code_refactor, code_review $0.15–0.25

Data json_minify, json_query, csv_to_json, hash, base64, convert $0.10–0.15

Media describe_image, probe_media $0.15

The price list is free to read: GET…