The core the other projects run on

Problem

Three things every agent in production needs and nobody builds before getting burned: a spend cap that refuses when it cannot read itself, an audit trail that answers "why did it decide that" with a rule code instead of generated prose, and a durable queue that does not lose work across a redeploy.

Approach

• →Extracted from a live application, then generalized. During the extraction, the review process found a bug that was in production at the time: a refused call was charging the next visitor's quota when a Redis EXPIRE failed between two round trips. Reproduced, fixed, with a regression test.
• →Python 3.12, 947 lines of source, 95 tests that need no Redis, no database and no network. CI builds a wheel and installs it into a clean virtualenv, so the package cannot silently stop being installable.

Stack

By the numbers