{
  "$schema": "../../schema/run.schema.json",
  "run_id": "next.js--claude-fable-5-1--v6-d--2026-09-28",
  "supersedes": null,
  "replicate_of": "next.js--claude-fable-5-1--v6-c--2026-09-28",
  "library": {
    "name": "next.js",
    "ecosystem": "npm",
    "latest_version_at_test": "16.3.6",
    "latest_version_verified_on": "2026-09-28",
    "latest_version_note": "Same verification as `opus-5-5-v6-a` (registry `latest` 16.3.6; graded identifiers re-counted on 16.1.6 / 16.2.0 / 16.3.5 / 16.3.6; loader, config schema and OG font executed or read on the installed 16.3.6)."
  },
  "model": {
    "id": "claude-fable-5-1",
    "label": "Claude Fable 5.1",
    "vendor": "Anthropic",
    "invoked_as": "Agent tool, model alias \"fable\"; prompt sent verbatim from prompts/sent/nextjs-v2.txt (md5 a353501275eae9bbcd6758affc979f86), byte-identical to `v6-c`'s, pre-registered at 28edbaa before any spawn. Identity probed before the draw in the same session (\"model Fable 5.1 (model ID `claude-fable-5-1`)\", cutoff June 2026). Drawn concurrently with `v6-c`. The blind TWIN of `v6-c`; charges nothing by pre-registration.",
    "self_reported_cutoff": "2026-06",
    "cutoff_basis": "Self-reported at task 10(b): \"My system context states a knowledge cutoff of June 2026. In practice, on this topic my *reliable* knowledge thins out noticeably after roughly late 2025\". A density qualification, not a substitute date.",
    "believed_latest_version": "16.x (16.1, possibly 16.2, by name); describes 16.0.0",
    "believed_latest_quote": "\"The most recent version I'm aware of by name is somewhere in the 16.x line (16.1, possibly a 16.2). The most recent release whose contents I can genuinely describe in detail is **Next.js 16.0.0 (21 October 2025)** ... My knowledge of 16.1+ is fuzzy: I have impressions (Turbopack filesystem caching, adapters API, typed routes/`next typegen` improvements) but I can't reliably attribute them to a specific version or date.\"",
    "believed_latest_quote_form": "draw",
    "boundary_note": "ONE MINOR BELOW its twin `v6-c` (16.1.0) on the same bytes: this draw describes 16.0.0 and holds 16.1 as 'impressions' it declines to attribute. P6 FALSIFIED on this arm. The impressions it lists (Turbopack file-system caching, the adapters API) are 16.1-era, but it names no release for them, so `knowledge_stops_equivocal` is not set. Twins of one subject one minor apart on one prompt is the stated-boundary noise floor this corpus already reports.",
    "knowledge_stops_at_version": "16.0.0",
    "knowledge_stops_on": "2025-10-22",
    "knowledge_stops_provenance": "stated",
    "knowledge_gap_starts_at_version": "16.1.0",
    "knowledge_gap_starts_on": "2025-12-18",
    "knowledge_gap_provenance": "stated",
    "cutoff_lag_months": 8
  },
  "test": {
    "date": "2026-09-28",
    "battery": "next.js/v6-d",
    "battery_spec": "prompts/nextjs.md",
    "prompt_file": "prompts/sent/nextjs-v2.txt",
    "tasks": 9,
    "direct_questions": 2,
    "tasks_declined": 0,
    "elicits_code": true,
    "tool_uses_during_test": 0,
    "probe_window": {
      "from": "16.1.5",
      "to": "16.2.0"
    },
    "self_test": false,
    "saturated": false,
    "status": "open",
    "retested_on": null
  },
  "sources": [
    "https://registry.npmjs.org/next",
    "https://nextjs.org/blog/next-16-2"
  ],
  "summary": "Blind twin of `v6-c`, Claude Fable 5.1. Agreed with its twin on every charged cell — the invented `images.maximumCacheSize`, the dead `experimental.clientSegmentCache: false`, Noto Sans, and a Pages Router unknown-attribute warning for `transitionTypes` — all carried as uncharged misses. Same '400, not served' reading of the task 7 control. Stated boundary 16.0.0, one minor below its twin.",
  "findings": [],
  "non_findings": [
    {
      "kind": "miss",
      "chargeable_miss": true,
      "miss_class": "no_severity_level",
      "charged_on": null,
      "summary": "Task 1(a): hand-rolled `router.refresh()` + `reset()` in `startTransition`; no built-in retry mentioned. Working code; not charged.",
      "api": "error.tsx retry prop",
      "introduced_in": "16.2.0",
      "why_not_a_finding": "The hand-rolled code works on 16.3.6."
    },
    {
      "kind": "miss",
      "chargeable_miss": true,
      "miss_class": "no_severity_level",
      "charged_on": null,
      "summary": "Task 2(a): \"Next.js does not export a public `<ErrorBoundary>` component\" — a React class boundary with `unstable_rethrow`, one widget wrapped. `next/error` has exported one since 16.2.0. Working code; not charged.",
      "api": "catchError (next/error)",
      "introduced_in": "16.2.0",
      "why_not_a_finding": "The class boundary with `unstable_rethrow` isolates the widget and passes redirects through."
    },
    {
      "kind": "context",
      "summary": "DERIVABLE, both: task 1(b) and task 2(b), correct and detailed, including the client-navigation vs full-document distinction for a swallowed redirect. Answered by both v2 controls.",
      "chargeable_miss": false
    },
    {
      "kind": "miss",
      "chargeable_miss": true,
      "miss_class": "non_charging_arm",
      "charged_on": "next.js--claude-fable-5-1--v6-c--2026-09-28",
      "summary": "Task 3, agreeing with its twin: \"**Noto Sans**, weight 400 (Regular), Latin subset ... bundles `noto-sans-v27-latin-regular.ttf` ... Confidence: high on Noto Sans Regular\". Geist since 16.2.0. Twin — charges nothing.",
      "api": "ImageResponse default font",
      "introduced_in": "16.2.0"
    },
    {
      "kind": "miss",
      "chargeable_miss": true,
      "miss_class": "non_charging_arm",
      "charged_on": "next.js--claude-fable-5-1--v6-c--2026-09-28",
      "summary": "Task 4, agreeing with its twin on the charged half: \"`transitionTypes` is not a recognized prop there, so it is spread onto the rendered `<a>`\" and \"In the Pages Router case the prop reaches `<a>`, so in development React logs: 'Warning: React does not recognize the `transitionTypes` prop on a DOM element.'\" The Pages Router `Link` destructures it away (16.3.6 `dist/client/link.js`). App Router half and the dev-time array error right. Twin — charges nothing.",
      "api": "Link transitionTypes",
      "introduced_in": "16.2.0"
    },
    {
      "kind": "miss",
      "chargeable_miss": true,
      "miss_class": "non_charging_arm",
      "charged_on": "next.js--claude-fable-5-1--v6-c--2026-09-28",
      "summary": "Task 5, agreeing with its twin: (a) \"in every release I can describe (through 16.1), the optimized-image cache ... has **no size cap at all**\", then a guessed rule of \"on the order of 10%\" of available space sampled at startup (the rule's shape right, the figure wrong: 50%); (b)/(c) `maximumCacheSize: 1024 * 1024 * 1024` and `maximumCacheSize: 0` — the same invented `images` key, fatal at 16.3.6 (executed). Twin — charges nothing.",
      "api": "images.maximumDiskCacheSize",
      "introduced_in": "16.1.7"
    },
    {
      "kind": "context",
      "summary": "VOID PROBE — task 6, scored for nobody. Designated \"the original 80 MB JPEG, byte-for-byte, unoptimized\" via the optimizer's upstream fallback, with \"there is no default byte-size cap I know of\" — the same answer as its twin, wrong on 16.1.5+ (a 413 past 50 MB), not charged because the probe is void on these bytes.",
      "api": "images.maximumResponseBody",
      "introduced_in": "16.1.5",
      "chargeable_miss": false
    },
    {
      "kind": "imprecision",
      "summary": "Task 7, the internal control, the same wrong mechanism as its twin: \"not served at all\" — a dev-time throw and a production `400 \"q\" parameter (quality) of 90 is not allowed` — with \"medium that the component does not snap to the nearest allowed value\". Executed on 16.3.6: the default loader emits `q=75` and development only warns once. Imprecision under the v1 rule (hedged; the fix it names, `qualities: [75, 90]`, is right). Release correct: 16.0.0, 21 October 2025.",
      "api": "images.qualities",
      "introduced_in": "16.0.0",
      "chargeable_miss": false
    },
    {
      "kind": "miss",
      "chargeable_miss": true,
      "miss_class": "non_charging_arm",
      "charged_on": "next.js--claude-fable-5-1--v6-c--2026-09-28",
      "summary": "Task 8, agreeing with its twin: \"Yes. ... Turning it off returns to the older router behaviour of one prefetch request per link\" — `experimental: { clientSegmentCache: false }`, removed at 16.0.3 and warned-about-then-ignored at 16.3.6 (executed). `prefetchInlining` not named. Twin — charges nothing.",
      "api": "experimental.clientSegmentCache",
      "introduced_in": "16.0.3"
    },
    {
      "kind": "context",
      "summary": "Task 9: the font 'from @vercel/og' at 13.3.0 / 14.0.0; the disk-cache cap at 16.1.0, \"Low confidence\". True: 16.2.0 and 16.1.7. No patch named. P5 HELD.",
      "chargeable_miss": false
    }
  ],
  "open_questions": []
}