The problem
Site audits are usually a report someone runs by hand, once, after the damage. The useful version runs on every pull request and tells you which of the 128 pages just lost its canonical tag.
What it does
Parallel crawler
Multi-threaded fetch with a politeness budget, so a full audit of a mid-sized site finishes in the time a CI step is allowed to take.
Structured-data validation
Schema.org parsed and checked rather than merely detected — an invalid JSON-LD block is worse than none, and only validation tells them apart.
Link graph and PageRank
Internal links resolved into a graph, so orphaned pages and rank sinks are visible as structure rather than inferred from a list of URLs.
Core Web Vitals
Field-shaped metrics collected per template, not per page, because templates are what you actually fix.
AI-crawler readiness
Checks what the newer generation of crawlers is permitted to read, which is now a robots.txt question with real consequences.
Snapshot diffs for CI
Every run is a snapshot; the interesting output is the difference from the last one. That is what turns an audit into a regression test.