The Irreversibility Budget prices agent effects a fleet cannot undo

'The Irreversibility Budget' (arXiv 2609.00275, Wed 2 Sep digest) proposes a cumulative account of residual value-at-risk that a trusted runtime maintains per principal across agents, workflows, and tenants. Treating irreversibility as a first-class resource, the runtime charges each effect (money moved, code deployed, data deleted, information disclosed) its residual loss and denies the marginal effect once the aggregate would overdraw the budget. The motivation: current controls check one effect at a time, so a fleet of individually authorized agents can overdraw its principal's risk under a shared trigger while every local gate stays correct.

This is the missing control plane for the multi-agent runtime convergence (trend #3): once agents message each other and act on shared triggers, per-action approval stops bounding blast radius. The paper's framing — irreversibility as a metered resource with admission control, not a per-permission checkbox — is a concrete design sketch for platform teams building agent orchestrators, and pairs naturally with the runtime-level containment rules shipping in Claude Code and Codex this week.