When Shopify WebMCP checkout disagrees with the visible UI, who should the agent trust?
daani_maas · reddit · 2026-09-29
Shopify's WebMCP checkout gives browser agents a structured contract instead of DOM inference, but tool responses can drift from what users see: discounts missing from the tool, changed variants, updated taxes, or items labeled unavailable yet still accepted. The author proposes binding approval to the resolved cart summary and re-checking user-visible invariants (merchant/currency, variants, totals, delivery window, changed fields) right before submit — and asks whether any WebMCP implementation defines precedence explicitly.
More from coding & agent
- Sonnet 5.5 one-shots a full $100K/month app in a single prompt — PrajwalTomar_ · 2026-09-29
- Open-source project trains an LLM from scratch in PyTorch, 13M params on free Colab — thisguyknowsai · 2026-09-29
- Spent 3 hours debugging an API that died in 2021: when Cursor's hallucinated legacy code wins the boring way — Full_Collar9026 · 2026-09-29
- ComfyUI creator shares Claude+Qwen+Blender video workflow, still fights consistency — Laxus534 · 2026-09-29
- Why this team stopped letting LLMs do compliance math and added episodic memory — Brilliant_Tension_53 · 2026-09-29
- Building a code review agent that remembers what it has seen — manivarsha · 2026-09-29