Composo

Composo builds AI evaluation systems that help teams find and control failures in production applications. Its platform connects to application traces, discovers recurring failure patterns and evaluates outputs against domain-specific criteria. Teams can use the results to block failing outputs, monitor quality and route uncertain cases to experts. The evaluation API returns a score between 0 and 1, an explanation and supporting sources.

Composo’s co-founders are Seb Fox, CEO, a medical doctor who previously led AI engagements at McKinsey’s QuantumBlack, and Luke Markham, CTO, whose machine-learning engineering experience includes Graphcore and Tessella. The evaluation engine assembles a fresh rubric from customer standards, documents and past expert corrections, using an ensemble of judge models sized to task complexity. Its clinical evaluation research examines why judges miss omitted information: checking a note against facts extracted from the underlying consultation helps recover errors that ordinary judging overlooks.

Composo serves healthcare, financial-services, legal and enterprise AI workflows. In 2026, the company reported more than one million production outputs evaluated and use by over 30 AI teams. Customers can use separate EU and US endpoints or self-host in their own cloud. They retain ownership of evaluation criteria, failure taxonomies, guardrail rules and expert correction data; ongoing platform maintenance and tuning are optional.