Production Agent Systems: Harnesses, Context, and Scalable Environments

Agent reliability is increasingly determined by runtime harnesses, persistent context, verification, and secure environments. Graphectory, Terminal-Universe, and Environment Evolution show measurable gains from diagnostics, rollback, reusable environments, and adaptive difficulty; recent sandbox networking work adds dynamic egress and DNS policy enforcement. HarnessDev remains a counterweight, showing that agents do not yet reliably design or evolve infrastructure at human quality.