Cool Company Raises · YC F26 · www.runmirrors.com

Mirrors launches at YC (Fall 2026)

Mirrors builds runnable staging environments for AI agents. It captures production traces from an agent's real sessions, reconstructs a working twin of the internal tools and APIs that agent calls, then replays those sessions against every prompt, model or tool change before it ships — so regressions surface in staging rather than in production. The gap it fills is that agents call bespoke internal services no standard test suite can reproduce, which matters most where a mistake is irreversible: issuing refunds, updating records, sending outbound messages. Founded in 2026 in San Francisco by Aryan Singhal (ML research at UT Austin and UCSB; six AI/ML papers published while in high school, three at NeurIPS). Y Combinator Fall 2026.