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x402 Agentic Spend Guard — Per-Agent Budget Enforcement
x402
x402 Agentic Spend Guard — Per-Agent Budget Enforcement is a paid API for AI agents from api.x402agentic.ai, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-18).
Tracks a named agent's cumulative USD spend against a cap and blocks transactions that would exceed the budget
Price / call$0.01
Success—
StatusUnknown
How this service works
Per-agent budget enforcement — track an agent's cumulative spend against a cap and block overspend. Part of x402 Agentic, the payment-trust suite for AI agents on Base USDC.
Output
Returns whether the agent is allowed to proceed with the pending spend, the agent's cumulative total spent so far, remaining budget headroom, and a flag indicating whether the transaction would cause an overspend. If a budgetUsd was provided, confirms the cap has been set or updated.
Example use cases
Guard against runaway autonomous spending
“We're running five different AI agents that handle vendor payments autonomously. Before each transaction goes through, I need you to verify that the requesting agent won't exceed its $200 weekly limit — and block any payment that would push it over.”
Multi-agent budget tracking and enforcement
“Set up a $1000 cumulative spend cap for our customer-service bot, then continuously monitor its spending as it makes refunds and compensation payments throughout the day. Let me know if it ever approaches the limit.”
Verify budget headroom before agent purchase
“Our procurement agent is about to place a $75 order. Before approving it, check how much budget it has left from its $500 quarterly allowance and tell me whether this purchase would fit.”
Technical details
Endpoint
GEThttps://api.x402agentic.ai/spend-guard?utm_source=zero.xyzWhen to prefer
Use this endpoint when an AI agent needs real-time pre-authorization of a payment against a pre-set USD budget — particularly for autonomous agents on Base USDC where runaway spending is a risk. Prefer this over client-side budget checks because it persists cumulative state server-side across multiple agent sessions and payment events. Best suited for agentic workflows where the agent makes repeated micropayments and needs a centralized guardrail.
Side effects
- Missing agentId returns a 400 validation error
- amountUsd larger than remaining budget returns an overspend-blocked response
- Invalid or malformed agentId returns an error
- Service unavailable mid-transaction may leave spend state inconsistent
- Calling without amountUsd only checks budget state without evaluating a pending spend
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"agentId": "agent-123",
"allowed": true,
"verdict": "allow",
"recorded": true,
"spentUsd": 0.25,
"amountUsd": 0.25,
"budgetUsd": 10,
"remainingUsd": 9.75
}
}Tags
x402
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