{
  "slug": "chrome-devtools-mcp-performance-summaries-include-crux-field-data-df8467bc1091",
  "title": "chrome-devtools-mcp performance summaries include CrUX field data",
  "tools": [
    "chrome-devtools-mcp"
  ],
  "tags": [
    "agent"
  ],
  "introduced_at": "2026-02-10T08:32:41.000Z",
  "announced_at": "2026-02-10T08:32:41.000Z",
  "effective_at": null,
  "date_basis": "source-publication",
  "status": "unknown",
  "how": {
    "incantation": "When reviewing a repository page’s performance, record a trace and inspect the stopped trace summary for CrUX field metrics alongside lab data. Set `--performance-crux=false` (or use `--no-performance-crux`) at server startup to disable sending trace URLs to the CrUX API.",
    "examples": [
      "navigate_page({\"type\":\"url\",\"url\":\"<repository-page-url>\"})",
      "performance_start_trace({\"autoStop\":false,\"reload\":false})",
      "performance_stop_trace({})"
    ],
    "gotchas": [
      "Version: 0.17.0",
      "autoStop (required): Whether to stop the trace automatically.",
      "reload (required): Whether to reload the selected page after tracing starts.",
      "--performanceCrux / --performance-crux: Boolean; defaults to true. Set false to disable sending URLs from performance traces to the CrUX API for field data.",
      "--no-performance-crux: Disable sending trace URLs to the CrUX API.",
      "filePath: For start/stop trace tools, path to save raw trace data; may be absolute or relative to the working directory.",
      "Prerequisite: Node.js v20.19 or newer maintenance LTS, Chrome current stable or newer, and npm.",
      "Prerequisite: Navigate to the desired URL before starting a trace if `reload` or `autoStop` is true.",
      "The server extracts primary navigation URLs from the trace, determined by insightSets.",
      "It fetches field metrics for each unique URL or origin.",
      "The `--performanceCrux`/`--performance-crux` boolean defaults to `true`.",
      "Performance tools may send trace URLs to the Google CrUX API."
    ]
  },
  "why_it_matters": "Review a performance trace for a repository page and compare lab metrics with real-user field metrics.",
  "sources": [
    "https://github.com/ChromeDevTools/chrome-devtools-mcp/releases/tag/chrome-devtools-mcp-v0.17.0",
    "https://github.com/ChromeDevTools/chrome-devtools-mcp/pull/733",
    "https://github.com/ChromeDevTools/chrome-devtools-mcp/blob/chrome-devtools-mcp-v0.17.0/docs/tool-reference.md",
    "https://github.com/ChromeDevTools/chrome-devtools-mcp/blob/chrome-devtools-mcp-v0.17.0/README.md"
  ],
  "rank": 0.98042,
  "judge": {
    "publish": true,
    "judge_model": "codex-cli/gpt-6-luna+typesafe/jev-1.13.0",
    "prompt_version": "extract-v7+enrich-v1+judge-v2x3+jev-publish-v1"
  },
  "review_state": "approved",
  "provenance": {
    "run_id": "ghtools-20261008",
    "verdict_id": "ghtools-20261008:ghtools-20261008-d675fd2fb076370b-1:gate",
    "evidence_hash": "00972f2002b9a73bbd5f0286c8e54f3ba27ae15d6cbeba384e098c0d2a9605b9"
  },
  "review": {
    "draft_hash": "6a44edb5585dd9296efa99ad64aedacab79a6b0410079f00c4fdf8bc47024950",
    "reviewer": "publication-gate",
    "reviewed_at": "2026-10-07T00:00:00.000Z",
    "decision": "ghtools-20261008:gate",
    "reason": "3 of 3 judge runs approved with p_yes >= 0.9 (mean 0.98 >= 0.9; 2 needed) and Jev gave 0.68 (>= 0.6 needed)."
  }
}