Agent-written Stripe integration caused duplicate charges; sandbox twins fix it
Common_Dream9420 · reddit · 2026-09-07
The author recounts a real incident: a Lovable-generated payment flow passed review, then caused duplicate charges in prod three days later because the webhook handler wasn't idempotent and a retry fired twice. Happy paths always work; auth failures mid-flow, declines after partial state, and flaky webhook sequences are what break agent-built integrations. The fix isn't smarter agents but realistic verification: FetchSandbox MCP ships sandbox twins of Stripe, Paddle, Twilio, Resend, Clerk, and WorkOS with failure scenarios pre-wired — agents import the spec via MCP, run full flows including bad paths, and attach a receipt URL to the PR.
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