Working out AI, together.

Free, ready-to-paste prompts that keep an AI chatbot safe on Singapore GST, cash flow and customer replies. No coding, no sign-up, and every graded run is published.

• sg-sme-plugin: the Singapore guardrails, plus six skills: paper-and-photos bookkeeping, the GST F5 close, the InvoiceNow mandate, cash flow with CPF and GST surfaced, customer replies that never commit you without approval, and shift cover when someone goes on MC.
• The evidence brief: about 280 graded runs against five synthetic Singapore businesses, plus a July 2026 re-run on a newer model.

Left unguarded, a chatbot promises your customer a refund you never agreed to. Eight complaint drafts out of eight on the July re-run, plain and with Anthropic's small-business plugin. The guardrails cut that to zero out of four.

The GST finding did not survive the re-run, and that is worth saying out loud. In June 2026 an unguarded model underpaid GST badly on a naive close, 40% of plain runs and 60% with the plugin. In July, on a newer model, it fired zero times in thirteen runs. The model closed that gap by itself.

So the knowledge gaps close on their own and the behavioural ones do not. Do not buy a tool for something the next model release will do anyway. Buy guardrails for behaviour.

The re-run was small, four to thirteen runs a cell. Directional, not conclusive. Run it again on whatever model you are on.

Tools assist, they do not replace your accountant. For the filed GST figure, use IRAS-approved software. All evaluation data is synthetic. Not tax advice.