Engineering notes
Occasional notes from building ClaroCal: the trade-offs behind the product, written up honestly. Latency, budgets, architecture, and the decisions we would defend in a code review.
These are working notes, not announcements. Each one covers a real decision from the codebase, the options we prototyped, and what we would tell a friend who was about to make the same call.
How cheap can an autonomous builder be?
We run a small overnight fleet of coding agents on ClaroCal. One night it burned a whole weekly plan allowance in about an hour. This note is the harness we built to find the cheapest model that still ships mergeable code, the first results, and the six ways the harness lied to us before it told the truth. It is written to be updated: new models get rows, the same models get re-run, and the case set stays frozen.
A regression suite for coding models: seven frozen fixes, hidden tests, a blind judge, and cost in plan percent.