Bill Drift Auditor

Inspiration

Recurring bills on a NAS (electricity, telecom, suppliers) go up, and nobody can tell whether the unit price changed or usage did. Document chat summarises; it does not close the arithmetic.

What it does

Bill Drift Auditor is a Markdown-only Skill for UGREEN AI NAS. For one company's bills in a folder it removes byte-identical copies, verifies each bill by arithmetic and a second read, and splits every change into a price effect and a usage effect with a re-addable sum line. It also lists new or dropped charges, possible duplicates and missing periods. Unverified bills are excluded and named. A winter usage rise is not reported as drift. Read-only; tags and saved reports need approval.

How it is built

SKILL.md plus four references (drift rules, report format, worked example, disclosure). It delegates to file-agent and document-agent and, after approval, knowledge-agent. A Python reference of the rules (not shipped; Skills may not contain scripts) has 24 passing offline tests. The Skill passes the official static checker (0 errors, 0 warnings).

Status and limits

Static checks and offline tests only. NAS runtime is untested (device access is finalist-only), the extract output format is unknown, and whether the NAS model follows the written rules is the finalist-day test. Tiered tariffs are not decomposed. No demand claim: the only public evidence found concerns invoice transcription. Synthetic data only; no third-party components.

Built With

• markdown
• python-(offline-reference-tests)
• ugreen-uliya-skill-kit