Cora

Cora is the email assistant and AI chief of staff that Every ships as one of its five products, alongside Spiral, Sparkle, Monologue and Proof. Kieran Klaassen runs it, and the four source notes keep returning to Cora for the same reason: it is the concrete case study behind «Compound Engineering», the place where an abstract claim about AI-native development gets tested against Gmail rate limits.

The email bankruptcy feature is the recurring episode. Klaassen assumed archiving 53,000 emails in bulk was a two-file job. Twenty minutes of agent research surfaced Gmail rate limits that break around 2,000 messages, system timeouts, and a long user wait; the feature became a three-day architectural problem. Later, 19 users were stuck on it, and an agent reading AppSignal logs found rate-limit errors being swallowed silently. That fix did not stay a fix: it became a permanent line in the @kieran-rails-reviewer checklist.

Cora is also where the tooling constraints are visible. It runs on the «Gmail API» with its strict quotas, and on «RubyLLM», a fast-moving gem poorly enough documented that Klaassen's agent had to read the test suite to discover undocumented v1.9 streaming support.

Every claims each of its five products is built and maintained mostly by a single person, serving thousands of daily users. Cora carries the weight of that claim. What the notes do not settle is how much of the result comes from the method and how much from Klaassen himself.