TraceLens v0.4.0

Release-aware performance budgets, native GitHub reporting, and a searchable documentation site.

Highlights

• Define global INP, LCP, CLS, and long-frames-per-session budgets in tracelens.yml.
• Add route-level interaction p75 thresholds and minimum sample requirements that fail closed when telemetry is missing.
• Run budgets from the CLI with human-readable or stable JSON output, selecting an explicit release or the newest captured release.
• Use leracherry/tracelens@v0.4.0 as a self-contained Node 24 GitHub Action.
• Publish results to the job summary, a downloadable JSON artifact, a dedicated GitHub Check, and one deduplicated pull-request comment.
• Run the Action in reporting-only mode while establishing baselines, with fork permission failures reduced to warnings.
• Browse a VitePress documentation site with local search, structured navigation, detailed browser and React setup, an interaction-debugging tutorial, and a system architecture guide.

Performance budget quick start

Create tracelens.yml:

minimumSamples: 20

performance:
  inp:
    p75: 200
  lcp:
    p75: 2500
  cls:
    p75: 0.1
  longFramesPerSession:
    max: 1

routes:
  /checkout:
    inp:
      p75: 150

Run it locally:

npx @leracherry/tracelens-cli@0.4.0 budget check \
  --config tracelens.yml \
  --file trace.json \
  --release 2.14.0 \
  --app billing-dashboard \
  --environment production

Or in GitHub Actions:

permissions:
  contents: read
  checks: write
  pull-requests: write

steps:
  - uses: actions/checkout@v5
  - uses: leracherry/tracelens@v0.4.0
    with:
      trace-file: artifacts/tracelens-events.json
      github-token: ${{ secrets.GITHUB_TOKEN }}

Documentation

The new documentation portal is published at https://leracherry.github.io/tracelens/. Start with browser instrumentation, React integration, or the slow-interaction walkthrough.

Compatibility and limits

Upgrade all TraceLens npm packages together to 0.4.0. The event protocol remains version 1. The GitHub Action is distributed with the repository release rather than as a separate npm package.

Budget results describe the supplied telemetry sample and do not establish statistical significance. Route budgets currently support interaction p75. The Action requires a JSON event artifact from an earlier workflow step; it does not collect browser telemetry itself.

Studio remains a local development tool with no authentication. Production React timing still requires a profiling-enabled React build, and browser API support varies.