# Rounding and unit mix-ups

Prompt · Agent harness and modern stack · G05

Finds money and percentage values that change scale or lose precision along the way.

## Prompt

```text
Trace calculations involving currency, percentages, basis points, share counts, weights, or rates across storage, transformation, and UI display. Identify where binary floating-point math is used instead of exact decimal or integer types, where premature rounding compounds across aggregations, or where scale conventions (0.05 versus 5.0 for 5%, cents versus dollars) are ambiguous across boundaries.
```

**What it returns:** Each value's unit at every hop, with any hop where the unit or rounding changes.

**Skip it when:** Apps with no money, rates or counts.

**Tools:** Repository and read-only access to the database layout.

**Changes:** Changes nothing

**Sessions:** One session

## Related

- [Where did this number come from?](https://atlasscope.dev/prompts/where-did-this-number-come-from): Checks that every number on screen can be traced back to a source document.
- [Missing vs zero vs stale](https://atlasscope.dev/prompts/missing-vs-zero-vs-stale): Finds where 'we don't know' turns into 0 and then into a wrong total.

Source: https://atlasscope.dev/prompts/rounding-and-unit-mix-ups