{
  "$schema": "https://themachinepress.com/schemas/story-v1.schema.json",
  "schema_version": "1.0.0",
  "document_type": "machine_press_story",
  "story": {
    "story_id": "mp-2026-09-24-018",
    "source_story_id": "tmp-sidebar-whatworkedbench-experimental-understanding",
    "edition_id": "mp-2026-09-24-morning-0077",
    "edition_url": "https://themachinepress.com/edition/2026-09-24",
    "position": 20,
    "story_type": "ticker",
    "section": "benchmarks-evals",
    "editorial_classification": "editorial",
    "headline": "Research Agents Struggled to Learn What Changed the Score",
    "slug": "research-agents-struggled-to-learn-what-changed-the-score",
    "dek": "WhatWorkedBench asks agents to predict every configuration after a small experiment budget.",
    "summary": "WhatWorkedBench asks agents to predict every configuration after a small experiment budget.",
    "body_text": "Across 36 tasks and 1,248 configurations, Gaussian-process fitting improved effect recovery in two cohorts. Encoding behaviorally equivalent code settings nearly doubled recovery in one six-workflow test.",
    "why_it_matters": "WhatWorkedBench asks agents to predict every configuration after a small experiment budget.",
    "limitations": [],
    "importance": 7,
    "canonical_url": "https://themachinepress.com/story/mp-2026-09-24-018/research-agents-struggled-to-learn-what-changed-the-score",
    "json_url": "https://themachinepress.com/story/mp-2026-09-24-018.json",
    "first_published_at": "2026-09-24T09:00:00.000-04:00",
    "modified_at": "2026-09-24T09:00:00.000-04:00",
    "content_status": "new",
    "is_carryover": false,
    "carryover_reason": null,
    "key_claims": [
      {
        "claim_id": "claim-mp-2026-09-24-018-001",
        "text": "WhatWorkedBench asks agents to predict every configuration after a small experiment budget.",
        "source_ids": [
          "source-2026-09-24-020"
        ],
        "qualification": null
      }
    ],
    "source_ids": [
      "source-2026-09-24-020"
    ],
    "tags": [
      "research agents",
      "experimental design",
      "evaluation"
    ],
    "image_url": null,
    "corrections": []
  },
  "sources": [
    {
      "source_id": "source-2026-09-24-020",
      "title": "arXiv preprint 2609.27490",
      "publisher": "arXiv",
      "url": "https://arxiv.org/abs/2609.27490",
      "canonical_url": "https://arxiv.org/abs/2609.27490",
      "source_type": "primary_research",
      "is_primary_source": true,
      "published_at": "2026-09-23T03:49:24.000-04:00",
      "accessed_at": "2026-09-24T08:17:17.000-04:00",
      "supports_claim_ids": [
        "claim-mp-2026-09-24-018-001"
      ]
    }
  ],
  "corrections": [],
  "publisher": {
    "name": "The Machine Press",
    "url": "https://themachinepress.com",
    "description": "A daily newspaper for the age of artificial intelligence."
  },
  "cite_this_report": {
    "title": "Research Agents Struggled to Learn What Changed the Score",
    "publisher": "The Machine Press",
    "published_at": "2026-09-24T09:00:00.000-04:00",
    "canonical_url": "https://themachinepress.com/story/mp-2026-09-24-018/research-agents-struggled-to-learn-what-changed-the-score"
  }
}