Fix an incorrect result
Use this guide when a TaxKit result appears to disagree with an official source, a published example or a known scenario.
Before you start
- Reproduce the calculation with the public SDK or HTTP API.
- Capture the input facts, calculator ID, jurisdiction, tax year and report.
- Find the owning package with What are you changing?.
Do not patch an HTTP response or SDK helper to mask a tax result. Incorrect tax behaviour belongs in the owning fact, rule, parameter, calculator or catalogue boundary.
Diagnosis
Work from evidence:
- Compare the result with an official source or known scenario.
- Inspect trace output and source references.
- Identify the first incorrect fact, parameter, rule or ledger component.
- Add a failing golden test or regression test before the fix.
- Fix the owning package.
- Re-run compatibility tests if public API or SDK output changes.
Tests
Your evidence should include:
- the failing scenario before the fix
- a golden test or regression test that would fail without the fix
- trace or ledger evidence when rule order or component values changed
- type tests when public input types changed
- API compatibility tests when HTTP output or errors changed
- SDK compatibility tests when SDK output or errors changed
Pull request evidence
Your PR must include source citations, the failing and passing test evidence, compatibility notes and release-impact notes. Use PR evidence checklist.