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Insights
Notes from production.
Payments, AI agents, and marketplace engineering — written from live systems, not tutorials.
Idempotent Stripe webhooks: the bugs that cost real money
Duplicate events, out-of-order delivery, and retries after timeout — the three webhook behaviors that break payment systems in production, and the patterns that survive them.
Read the note →Letting an AI agent near your orders: the guardrail spec
Scoped permissions, idempotent tools, human gates on money — how we let agents do real work without trusting them.
In progressBuilding an MCP server for a commerce backend
What Model Context Protocol changes for SaaS products, and a walkthrough of a production-shaped server.
In progressThese notes come from systems we run.
If your platform has the same problems, the fastest fix starts with the fixed-price audit.