Engineering and research deep-dives from the team building Viktor.
Our co-founder gave four AI agents four separate jobs on a Friday evening. An hour later they had names, a shared plan and a release owner. Nobody had told them about each other.
Most agent harness code works around model weaknesses, and workarounds expire with every release. The test behind every Viktor harness decision: will this still be useful for Fable 10?
We ran OpenAI's new Sol, Terra, and Luna against Claude Opus 4.8, Sonnet 5, and Fable 5 on real agent work. The frontier moved — and it has a personality.
How Viktor's thread engine is designed around prompt caching: SDK instead of tool loading, append-only threads, in-cache compaction, and an 80% cost cut.
