Financial UI principles

Preserve precision

Treat token quantities as decimal strings and money as integer minor units or BigInt. The included finance module supports exact calculations. Formatting should happen after calculation, with a clear rounding rule and currency unit.

• Reject invalid precision, negative amounts where unsupported, and exponent notation.
• Keep totals based on the full relevant balance, even when a list is filtered.
• Show whether a fee is deducted from the amount or added to it.

Explain the assumptions

A displayed yield needs a period and calculation basis. Simple annual estimates, APY, and compounding are different models. Put relevant fees, term, quote source, and excluded costs near the result.

Make state explicit

Keep quotes, estimates, drafts, saved plans, and executed actions distinct. Do not turn a successful local save into a “paid”, “invested”, or “filled” message. Connect real services only after defining authentication, permissions, data freshness, and failure handling.

Use the acceptance criteria

Each Skill includes references/acceptance.md. Use it to verify the relevant financial boundaries and interactions after customization. Include very small amounts, excessive fees, missing data, and damaged local records where the product supports those cases.