treosh/lighthouse-ci-action assertion failed (budget exceeded)

lighthouse-ci-action fails when configured assertions (performance score, resource budgets) are not met. This is a quality gate firing, not an infrastructure error.

What this error means

The Lighthouse step fails with "Assertion failed" or a budget exceeded message and a non-zero exit.

Assertion failed: "categories:performance" failed: expected >=0.9 but got 0.72
1 result(s) did not meet assertions.

Common causes

Real regression

The page regressed below the configured score or budget threshold.

Thresholds too strict

Assertions are tighter than the app realistically meets in CI.

How to fix it

Fix the regression or tune the assertions

1. Inspect the Lighthouse report to find the failing category/budget.
2. Fix the regression, or adjust the assertion config to a realistic threshold.
3. Re-run; assertions now pass.

- uses: treosh/lighthouse-ci-action@v12
  with:
    configPath: ./lighthouserc.json
    uploadArtifacts: true

How to prevent it

• Set assertion thresholds to values CI can consistently meet.
• Treat budget failures as actionable performance regressions.

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