Prototype coverage
Current coverage targets trusted Playwright Test 1.64.1 / trace schema 10 artifacts, tested against a small synthetic Chromium corpus. Production diagnostic accuracy and general DOM comparison are not established.
IN DEVELOPMENT
Follow the difference.
Three synthetic examples. Explore what changed, and what the evidence can’t tell you.
Comparison scenarios
Same request. Different response.
Investigation leadHTTP response
Failed attempt
503 · unavailableRetry
200 · OKInvestigate the changed response.
Root cause: unknown
Inspect the evidence
A controlled service failure on the first attempt becomes a successful response on retry.
| Observed signal | Failed attempt | Retry |
|---|---|---|
| HTTP response | 503 · unavailable | 200 · OK |
| Console error | Recorded | Not observed |
| Aligned assertion | Failed | No recorded error |
The response changed alongside the assertion outcome. That is a lead to investigate, not proof that the response caused the failure.
A locator with more than one match.
Investigation leadLocator operation
Failed attempt
Strict-mode violationRetry
No recorded errorInvestigate multiple matching elements.
Root cause: unknown
Inspect the evidence
The controlled fixture renders two identically named Save buttons on the first attempt and one on retry.
| Observed signal | Failed attempt | Retry |
|---|---|---|
| Locator operation | Strict-mode violation | No recorded error |
| Action inputs | Same locator | Same locator |
| Aligned action | Failed | No recorded error |
The recorded strict-mode error supports a locator-ambiguity lead. The fixture’s button count is known setup, not a general DOM comparison capability.
A passing retry is not an explanation.
UnknownAligned assertion
Failed attempt
FailedRetry
No recorded errorNot enough evidence for a cause.
Root cause: unknown
Inspect the evidence
The controlled fixture changes from Pending to Ready, but the captured evidence does not explain the backend decision.
| Observed signal | Failed attempt | Retry |
|---|---|---|
| HTTP response | 200 · OK | 200 · OK |
| Console error | Not observed | Not observed |
| Aligned assertion | Failed | No recorded error |
Different server-side mechanisms could produce the same visible behavior. The prototype leaves the result unknown instead of guessing.
Illustrative data. No traces are uploaded or analyzed on this page.
Technical notesTechnical notes and privacy
Technical notes & privacy
Evidence has limits
A recorded difference is an investigation lead, not proof of a cause. Missing capture, repeated requests, or changed action inputs can leave the result unknown. “Not observed” does not mean “never happened.”
Local does not mean redacted
Traces and reports can contain sensitive application data. Treat both with the same care. The examples on this page are handwritten summaries of controlled fixtures; this website does not process traces.