Spend limits before x402 payments: sipi.bot as an agent-first guardrail
x402 is the protocol for autonomous agent-to-agent payments in USDC. But it doesn't decide whether the agent *should* spend at all — that's sipi.bot's job. One call before the x402 transaction approves, blocks, or flags the spend against your policy.
The gap in agent-commerce infrastructure
The agent economy is building payment rails fast: x402 (Coinbase), AP2 (Google), and agent wallets are all solving the *how* of agent spending. But nobody is solving the *whether* — should this specific agent, at this specific time, pay this specific merchant, this specific amount?
sipi.bot fills that gap. Your agent calls sipi.bot before it signs an x402 payment, and the firewall evaluates the transaction against your rules: per-tx caps, daily totals, velocity, merchant allow/block, category limits, time windows, and an approval threshold that flags big spends for a human.
How they compose
Agent → sipi.bot (/v1/transactions/evaluate) → APPROVED → Agent signs x402 USDC payment on Base mainnet → Payment settles on-chain Agent → sipi.bot → BLOCKED (merchant not on allowlist) → Agent stops, explains to user, no payment made
The architecture is additive: sipi.bot is the guardrail upstream of the payment rail. x402 is the money movement; sipi.bot is the spending policy. Both are open-source infrastructure for the agent economy.
Frequently asked
Does sipi.bot replace x402?
No. x402 is a payment protocol for USDC transfers between agents. sipi.bot is a spend firewall that decides whether a transaction should proceed — it sits upstream of x402 and approves the spend before the payment is signed.
Can sipi.bot and x402 be used together?
Yes. The agent calls sipi.bot first, and if the decision is APPROVED, it then signs the x402 payment. If BLOCKED or FLAGGED, no payment occurs. The two are complementary infrastructure.
Does sipi.bot handle the x402 payment itself?
No. sipi.bot is a policy engine, not a payment processor. It evaluates the transaction and returns a decision; your agent or payment stack executes the actual transfer.