Retries are ambiguous. Duplicate side effects aren't. SafeAgent durably claims a logical action and keeps uncertain outcomes blocked until they are reconciled. Payments, webhooks, and agent tool calls still require provider evidence for end-to-end outcome certainty.
The gap between an action firing and your code confirming it fired is where duplicates come from. These are the categories where that gap has a direct dollar or trust cost.
This is the actual failure mode — mash the button and watch one side fire a duplicate order on every click while the other side blocks every repeat after the first. Full interactive demo, live below.
Not a simulation. Six confirmed SKIP events from a live trading session on the full stack: DashClaw, SafeAgent, Mycelium Trails, Base/Arbitrum, broker Alpaca.
MIT-licensed claim-before-execute guard. About 10 lines to add to any agent, workflow, or webhook handler.