{
  "slug": "wrangler-deploy-versions-upload-and-preview-upload-source-maps-by-default-2b5ff9de329b",
  "title": "wrangler deploy, versions upload, and preview upload source maps by default",
  "tools": [
    "wrangler"
  ],
  "tags": [
    "agent"
  ],
  "introduced_at": "2026-10-13T09:35:28.000Z",
  "announced_at": "2026-10-13T09:35:28.000Z",
  "effective_at": null,
  "date_basis": "source-publication",
  "status": "unknown",
  "how": {
    "incantation": "When deploying, uploading a version, or creating a preview and you want stack traces mapped to original source, leave `upload_source_maps` unset for Wrangler’s default map generation and upload. Set it to `true` for strict behavior or `false` to opt out; deploy and version upload also accept `--no-upload-source-maps`.",
    "examples": [
      "npx wrangler deploy",
      "npx wrangler versions upload [PATH]",
      "wrangler preview [<SCRIPT>] [OPTIONS]"
    ],
    "gotchas": [
      "Version: 4.150.0",
      "upload_source_maps: Boolean Wrangler config key. Omit it for default generation and upload on deploy, version upload, and preview; set `true` for strict behavior or `false` to opt out.",
      "--upload-source-maps: Boolean flag to include source maps when uploading a Worker; setting it to `true` retains strict behavior.",
      "--no-upload-source-maps: Opts out of source map uploads for deploy and version upload.",
      "[PATH]: Path to a Worker entry point or a directory of static assets for `versions upload`.",
      "[<SCRIPT>]: Optional script argument for `wrangler preview`.",
      "Prerequisite: For frameworks or custom builds, the build tool must generate source maps; Wrangler uploads maps from an existing build.",
      "Prerequisite: The documented minimum Wrangler version for `versions upload` is 3.40.0.",
      "In the default mode, unresolvable source maps are skipped rather than failing the upload.",
      "`wrangler build --experimental-cf-build-output` includes source maps only when `upload_source_maps = true`.",
      "`--no-upload-source-maps` is available for deploy and versions upload."
    ]
  },
  "why_it_matters": "Deploy, upload a version, or preview a Worker and make logged stack traces point to the original source.",
  "before": "Previously, source map uploads required `upload_source_maps` to be set in config or via `--upload-source-maps`; setting it to `true` kept strict behavior.",
  "sources": [
    "https://github.com/cloudflare/workers-sdk/releases/tag/wrangler%404.150.0",
    "https://developers.cloudflare.com/workers/wrangler/commands/workers/",
    "https://developers.cloudflare.com/workers/observability/source-maps/"
  ],
  "rank": 0.95055,
  "judge": {
    "publish": true,
    "judge_model": "codex-cli/gpt-6-luna+typesafe/jev-1.13.0",
    "prompt_version": "extract-v7+enrich-v2+judge-v2x3+jev-publish-v1"
  },
  "review_state": "approved",
  "provenance": {
    "run_id": "daily-20261013",
    "verdict_id": "daily-20261013:daily-20261013-39b158b73164c212-0:gate",
    "evidence_hash": "5307e7ad48f81011632ae99af8198ad0e20251eac39344c19af500ce87eac04a"
  },
  "review": {
    "draft_hash": "415d1d255c83a2958812a60c6254ebe53d824e76971b679bd4f05cb0d537fd08",
    "reviewer": "publication-gate",
    "reviewed_at": "2026-10-13T09:35:28.000Z",
    "decision": "daily-20261013:gate",
    "reason": "3 of 3 judge runs approved with p_yes >= 0.9 (mean 0.95 >= 0.9; 2 needed) and Jev gave 0.83 (>= 0.6 needed)."
  }
}