{
  "slug": "heroku-config-get-json-distinguishes-unset-and-empty-config-vars-32d3356843b3",
  "title": "heroku config:get --json distinguishes unset and empty config vars",
  "tools": [
    "heroku"
  ],
  "tags": [
    "agent"
  ],
  "introduced_at": "2026-02-10T19:50:31.000Z",
  "announced_at": "2026-02-10T19:50:31.000Z",
  "effective_at": null,
  "date_basis": "source-publication",
  "status": "unknown",
  "how": {
    "incantation": "When checking whether an app config var is unset or set to an empty string, run `heroku config:get <KEY> --app <APP> --json`. The JSON output distinguishes unset (`null`) from empty string (`\"\"`).",
    "examples": [
      "heroku config:get <KEY> --app <APP> --json"
    ],
    "gotchas": [
      "Version: v10.17.0",
      "KEY (required): Name of the config var key.",
      "--app=<value> (required): App to run the command against.",
      "--json: Output in JSON format; unset is `null` and an empty string is `\"\"`."
    ]
  },
  "why_it_matters": "When checking whether a Heroku app config var is unset or set to an empty string, request structured output.",
  "before": "Previously, `heroku config:get KEY` returned empty output for both unset and empty-string config vars, so they could not be distinguished.",
  "sources": [
    "https://github.com/heroku/cli/releases/tag/v10.17.0",
    "https://github.com/heroku/cli/pull/3464",
    "https://devcenter.heroku.com/articles/heroku-cli-commands"
  ],
  "rank": 0.97028,
  "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": "wave2a-20261017",
    "verdict_id": "wave2a-20261017:wave2a-20261017-2df7642fdfafb0c1-1:gate",
    "evidence_hash": "865e15f24c83a65e1393ba9cb837692a7ce2d80e014806ef5c09baffb2616f3f"
  },
  "review": {
    "draft_hash": "d66a067dea24c260afc3a951857546f901d7f6e36bd4dcd2e5ce4e357986bcd7",
    "reviewer": "publication-gate",
    "reviewed_at": "2026-10-07T00:00:00.000Z",
    "decision": "wave2a-20261017:gate",
    "reason": "3 of 3 judge runs approved with p_yes >= 0.9 (mean 0.97 >= 0.9; 2 needed) and Jev gave 0.79 (>= 0.6 needed)."
  }
}