Declare the automated nature of the transaction explicitly where the PSP or merchant supports it: Stripe's PaymentIntent accepts a payment_method_options field where you can supply relevant context; some payment flows accept a 'customer present: false' or equivalent machine-initiated flag.
Maintain consistent metadata across all agent-initiated charges from the same principal: customer ID, billing address, and user-agent string should not change per-transaction; erratic metadata is a primary fraud signal.
Avoid behavioral patterns that resemble card testing: do not attempt multiple small charges across many merchants in rapid succession; introduce natural spacing between purchases if the agent is processing a queue.
Pre-register the agent's spending pattern with your PSP account team if volume is significant — an anomaly alert on the PSP side for a pattern you know is legitimate can be suppressed proactively.
If a transaction is declined with a fraud-type code (do-not-honor, generic decline, card flagged), do not retry automatically; surface to the human and initiate a PSP dispute review process instead.
Log the full decline code and PSP response for every failed transaction; patterns in decline codes (repeated do-not-honor across different merchants) indicate a card-level flag that requires human intervention with the issuing bank.
Known gotchas
Agents that browse and then immediately purchase look different from human shopping behavior — the time-on-page and click patterns before checkout are near-zero; some fraud models score behavioral biometrics, so expect higher decline rates on merchant fraud models even with a valid card.
VPN or cloud-egress IP addresses used by agent infrastructure are disproportionately represented in fraud databases; use IP addresses associated with the human principal's region where possible, or work with your PSP to whitelist your infrastructure IPs.
Card networks can flag a card at the network level based on aggregate patterns across merchants — a card used by an agent for many merchants in a day may be flagged network-wide, not just at one merchant; this requires escalation to the card issuer, not the merchant.
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp