x402 · MCP · USDC on Base
PayStage sits in front of an agent's wallet and answers one question before money moves:
should this payment happen? Preflight checks return pay, review, or do_not_pay.
Early stage. Packages are Available soon — not yet on npm.
Small, focused pieces that compose into a payment safety layer.
An MCP server that evaluates a proposed x402 payment against a local policy file and returns a verdict before the agent signs anything.
npx -y @paystage/preflightNot yet published to npm. Command shown for reference.
Declarative rules for spend limits, allowed payees, and allowed networks.
One policy.json per agent.
Known-good payees pass. Unknown payees route to review instead of silently paying.
Per-call and rolling budget limits so a runaway agent can't drain a wallet.
Every verdict recorded with the inputs that produced it, for later review.
Policy-driven verdicts for x402 payments over MCP. Not yet on npm.
Richer rules: per-asset limits, time windows, per-tool budgets.
Signals beyond the allowlist for deciding when to escalate to review.
Structured logs and summaries of what an agent paid and why.