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SignGate Swap Preflight — x402 Agent Buyer Risk Check
x402
SignGate Swap Preflight — x402 Agent Buyer Risk Check is a paid API for AI agents from base-agent-preflight.bytoken2023.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).
Performs a pre-purchase risk and governance check on a token swap before an AI agent spends USDC via the x402 protocol on Base.
Price / call$0.01
Success—
StatusUnknown
How this service works
Machine-payable service intelligence for discovering, verifying, and monitoring identity, risk, authorization, execution-preflight, and evidence APIs before autonomous agents spend.
Output
Returns a JSON object containing the network identifier, product type ('swap-preflight'), and an assessment block with a numeric risk_score, a categorical risk_level (e.g. 'low', 'medium', 'high'), and a flags array listing any specific governance concerns detected. An empty flags array with risk_level 'low' indicates the swap is cleared for agent execution.
Example use cases
Pre-swap safety gate for autonomous agent
“Before my trading agent swaps 100 USDC into token 0x833589fcd6edb6e08f4c7c32d4f71b54bda02913 on Base, run the SignGate preflight so I can confirm the risk score is low enough to proceed.”
Slippage and risk screen before DeFi purchase
“My agent wants to swap token 0x4200000000000000000000000000000000000006 for 0x833589fcd6edb6e08f4c7c32d4f71b54bda02913 on eip155:8453 with 100 bps max slippage — can you do a preflight risk check and tell me if there are any flags?”
Governance approval check before x402 tool purchase
“Check whether swapping from 0x4ed4E862860beD51a9570b96d89aF5E1B0Efefed to 0x833589fcd6edb6e08f4c7c32d4f71b54bda02913 for 25 USDC on Base passes the buyer governance policy before my agent commits.”
Technical details
Endpoint
GEThttps://base-agent-preflight.bytoken2023.workers.dev/v1/x402/agent-risk/swap-preflightWhen to prefer
Use this endpoint when an AI agent is about to execute a token swap on Base via the x402 protocol and you need a lightweight, paid governance signal (risk score + flags) before committing funds. Prefer this over generic on-chain simulation when you specifically need buyer identity and policy alignment checks rather than execution simulation. Best suited for agentic pipelines that enforce a preflight gate before any DeFi spend.
Side effects
- Missing required query parameters (chain, token_in, token_out) results in a 400 Bad Request
- Invalid Ethereum address format for token_in or token_out returns a validation error
- Unrecognized or unsupported chain identifier returns an error response
- Service unavailability on Cloudflare Workers returns a 503
- Payment of $0.01 USDC via x402 fails if agent wallet lacks sufficient balance
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"network": "eip155:8453",
"product": "swap-preflight",
"assessment": {
"flags": [],
"risk_level": "low",
"risk_score": 0
}
}
}Tags
x402
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