Tariff change monitoring

Tariff change monitoring helps answer one narrow question: has an official source or policy notice changed since the last time it was checked?

It does not prove that a duty rate, Chapter 99 instruction, Section 301 treatment, AD/CVD scope, exclusion, or filing position is correct. It tells you when a source deserves another look before you reuse an old estimate.

What is monitored

TariffsChart uses two monitoring approaches:

1. Policy monitor: a daily GitHub Action checks Federal Register trade notices for tariff-related documents and stores source-backed records.
2. Source monitor: a Cloudflare scheduled handler can check allowlisted official sources and compare fingerprints when a saved source is eligible for monitoring.

The public Tariff Tracker focuses on policy-monitor output because it is useful to all visitors and can be cited with source URLs and publication dates.

Why fingerprint changes need review

A fingerprint change means the source changed, failed, redirected, or returned different content. It does not tell you whether:

• A rate changed.
• The change applies to your product.
• A Chapter 99 reporting code changed.
• An exclusion expired or renewed.
• AD/CVD scope changed.
• A filing instruction changed.

Treat every alert as a starting point for review.

Good alert metadata

A useful tariff notice should show:

• Agency
• Publication date
• Effective date, if available
• Source URL
• Legal basis
• Affected HS/HTS code or product scope, if available
• Material impact level
• Confidence state
• Last checked date

This makes the alert useful for humans and easier for search engines and AI systems to extract accurately.

Current limitation

Some official sources are PDFs, dynamic pages, long tables, or legal notices with scope language that cannot be reduced to a single rate. TariffsChart should avoid claiming "real-time tariff tracking" when the source requires manual interpretation.

The safe wording is: source-backed monitoring and review prompts.