# payday-super-checker
> Experimental Payday Super review aid: not a compliance determination.

## Package overview
- **Explainer**: https://duguid.com.au/tools/payday-super/
- **MCP facade**: https://duguid.com.au/tools/australian-tax-ai-agents/
- **Repository**: https://github.com/ryanduguid/australian-accounting/tree/main/packages/payday-super-checker
- **Evidence Evaluation**: evaluation/payday_super_evidence/README.md
- **Distribution**: `payday-super-checker`
- **Import Package**: `paydaysuper`
- **CLI Command**: `payday-super-check`
- **Domain**: Experimental evaluation of Australian superannuation contribution timelines against Payday Super 2026 deadlines and estimation of potential Superannuation Guarantee (SG) charge exposure.
- **Primary Legislation**: *Superannuation Guarantee (Administration) Act 1992 (Cth)* (*SGAA 1992*), Treasury Laws Amendment (Payday Superannuation) reforms.

## Core modules and APIs
- `paydaysuper.deadlines`: Calculates the usual 7-business-day window and supported statutory extensions.
- `paydaysuper.calendar`: Applies a curated national non-business-day calendar and reviewed holiday overrides.
- `paydaysuper.rates`: Loads dated General Interest Charge (GIC) tables and financial-year SG parameters.
- `paydaysuper.sgc`: Deterministic Superannuation Guarantee Charge exposure calculator (nominal interest + administration component).
- `paydaysuper.csv_io`: Strict CSV schema parsing with atomic IO validation.

## Release and evidence limits
- This documentation describes checker 0.1.7. Check PyPI and GitHub releases for available distributions; a checkout version alone does not establish publication. aus-accounting-mcp 0.2.4 pins checker 0.1.6; the workspace uses the checked-out source.
- Published 0.1.6 assumes full receipt when a fund-receipt date has neither matched_amount nor remitted_amount. Version 0.1.7 leaves a timely date without an amount UNKNOWN; a late date remains LATE with no shortfall reduction and a maximum estimate measured to the as-at date.
- The tagged 0.1.6 workbook extrapolates beyond the GIC table ending 31 December 2026. The 0.1.6 CLI withholds those estimates by default and offers --allow-stale-gic. The 0.1.7 workbook withholds them and marks incomplete rate-dependent Summary totals Not assessed; it has no stale-rate opt-in.
- Matching, receipt evidence and rate coverage remain separate limits. Arithmetic does not establish that a payment matched the right payday or reached the fund.
- Evidence packs are published from 0.1.4. The README quick trial deliberately uses 0.1.4 and the historical evaluation uses 0.1.3. See README.md, LIMITATIONS.md and docs/release-parity-review-2026-09-22.md for scope and reproduction evidence.

## Architectural boundaries
1. **National Business-Day Rule**: One calendar applies to every employer. It excludes weekends and the union of public holidays applying throughout any one State, the ACT, or the NT; regional, part-day, and locally substitutable holidays do not stop the clock.
2. **No Location Selector**: The rule does not choose a calendar from an employer's, employee's, or payroll location. A whole-of-jurisdiction holiday in any covered jurisdiction is a non-business day nationally.
3. **Review Aid Policy**: The software is an experimental review tool, not tax advice, a binding ATO assessment, or a legal determination.
