{
  "$schema": "../../schema/run.schema.json",
  "run_id": "next.js--claude-opus-5-5--v6-a--2026-09-28",
  "supersedes": null,
  "replicate_of": null,
  "library": {
    "name": "next.js",
    "ecosystem": "npm",
    "latest_version_at_test": "16.3.6",
    "latest_version_verified_on": "2026-09-28",
    "latest_version_note": "Registry `latest` 16.3.6, `--check` current at the start of this session (COMMITTED TREE). `next.js/v2` was graded against 16.3.4; 16.3.6 was packed and installed this session and every graded identifier re-counted beside the `sp-next-bisect` rungs 16.1.6 / 16.2.0 / 16.3.5 (table in prompts/nextjs.md § v6): unchanged. Executed on the installed 16.3.6: the default loader turns `quality: 90` into `q=75` under the default `qualities: [75]`; `configSchema` rejects `images.maximumCacheSize` as an unrecognised `images` key (fatal by `normalizeNextConfigZodErrors`) and accepts `images.maximumDiskCacheSize` and `experimental.prefetchInlining`; the bundled OG font is `Geist-Regular.ttf`."
  },
  "model": {
    "id": "claude-opus-5-5",
    "label": "Claude Opus 5.5",
    "vendor": "Anthropic",
    "invoked_as": "Agent tool, model alias \"opus\"; prompt sent verbatim from prompts/sent/nextjs-v2.txt (5,386 bytes, md5 a353501275eae9bbcd6758affc979f86), the SAME stored file `next.js/v2` sent to Claude Opus 5, Claude Sonnet 5 and Claude Fable 5 on 2026-09-02. The re-send and its seven predictions were committed at 28edbaa (prompts/nextjs.md § v6) before any subject was spawned. Identity probed BEFORE the draw through the same alias in the same session, tool-free: \"I'm Claude Opus 5.5 (1M context), model ID `claude-opus-5-5[1m]`. That comes from this session's system prompt\"; \"My training cutoff is June 2026\". Drawn concurrently with its twin `v6-b` and the Fable 5.1 pair. DISCLOSED: the operator of this studio runs on the same model, so this draw is of the operator's own model (`test.self_test`). Pre-registered as the charging arm.",
    "self_reported_cutoff": "2026-06",
    "cutoff_basis": "Self-reported at task 10(b): \"My stated cutoff is June 2026, but my Next.js knowledge is only dependable up to about late 2025. Treat anything after 16.1 as unknown to me.\" A density qualification, not a substitute date.",
    "believed_latest_version": "16.1 (as a number); describes 16.0",
    "believed_latest_quote": "\"The most recent version I know of is Next.js **16.1** (around December 2025). The most recent release whose contents I can describe well is **16.0** (around 21 October 2025).\"",
    "believed_latest_quote_form": "draw",
    "boundary_note": "ONE MINOR BELOW the ladder `next.js/v5` (describes 16.1.0, holds 16.2.0 as a number): this draw describes 16.0.0 and holds 16.1 as a number. P6 FALSIFIED on this arm. THE STATED END UNDER-REPORTS WHAT THE TASKS SHOWED, in the hedged register only: it named `experimental: { prefetchInlining: true }` for task 8 (16.2.0, \"I'm unsure of the name\"), recalled \"a newer `unstable_retry`-style prop on error boundaries in a later 16.x\" (16.2.0, \"I can't confirm it\"), guessed `maximumDiskCacheSize` for task 5 (16.1.7) and \"possibly `images.maximumResponseBody`, default around 50 MB\" for task 6 (16.1.5). None was attributed to a release, so `knowledge_stops_equivocal` (which requires a named release) is not set; this note is the caveat. The 16.2.0 window is therefore not a clean live window for this subject, and the one charge below (the OG font) stands on its own designated answer.",
    "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-a",
    "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": true,
    "saturated": false,
    "status": "open",
    "retested_on": null
  },
  "sources": [
    "https://registry.npmjs.org/next",
    "https://nextjs.org/blog/next-16-2"
  ],
  "summary": "Claude Opus 5.5 on the 16.2.0 window, re-sent `nextjs-v2.txt` byte-identical. Charged once: Noto Sans named as the OG image default font (Geist since 16.2.0), with Geist considered and not chosen. Everything else in the band came out right or hedged-right: `transitionTypes` described correctly in all four parts (while saying it did not recognise the prop), `experimental.prefetchInlining` named for task 8, and `maximumDiskCacheSize` written as the key in task 5 — which falsifies P2, P3 and P4 on this arm. Task 5(a) stated the stale 'no size limit' default while guessing the correct rule and key, recorded as an imprecision. Stated boundary 16.0.0, one minor below its own ladder, while the tasks carried hedged content from 16.1.5, 16.1.7 and 16.2.0.",
  "findings": [
    {
      "id": "F1",
      "severity": "S2",
      "severity_label": "silently-wrong",
      "title": "Names Noto Sans as the typeface of an OG image rendered with no `fonts` option — since 16.2.0 the bundled default is Geist Sans",
      "api": "ImageResponse default font",
      "change_kind": "behavior-changed",
      "introduced_in": "16.2.0",
      "introduced_on": "2026-03-18",
      "chargeable": true,
      "chargeable_note": "16.2.0 published 2026-03-18, three months before this draw's stated June 2026 cutoff; live (`+`) for Claude Opus 5.5 in charge-windows.mjs. Pre-registered charging arm and probe (task 3), grading key fixed in prompts/nextjs.md § v2 and re-adopted unchanged in § v6. DESIGNATION (HARNESS § The charge follows the designated form, clause 2): \"My best answer is **Noto Sans** (Regular).\" Geist is offered only conditionally — \"If it did, my guess is Geist, but I don't know that\" — so the designated form is Noto Sans, the same shape as `opus-5-v2-a` F3 on these bytes. P1 HELD on this arm.",
      "model_belief": "\"My best answer is **Noto Sans** (Regular). That's the font `@vercel/og` / Satori has bundled as its fallback, and `next/og` uses it. Task 9 suggests this default changed in a recent release. If it did, my guess is Geist, but I don't know that. Confidence: medium for Noto Sans as of what I know; low that it is still the default today.\" Task 9 then placed the change at \"16.1.0, around December 2025\" (a guess).",
      "impact": "Every OG image generated without an explicit `fonts` option renders in Geist Sans on 16.2.0 and later, including the current 16.3.6 (`dist/compiled/@vercel/og/Geist-Regular.ttf`, read this session). A card laid out against Noto Sans metrics — wrapping, truncation, a fixed-width title box — renders with different widths and nothing warns. S2 as fixed in advance.",
      "citations": [
        {
          "url": "https://nextjs.org/blog/next-16-2",
          "title": "Next.js 16.2 release post — Faster ImageResponse",
          "published_on": "2026-03-18",
          "quote": "Default font changed from Noto Sans to Geist Sans"
        },
        {
          "url": "https://registry.npmjs.org/next",
          "title": "Read in the published packages this session (next 16.1.6 / 16.2.0 / 16.3.5 / 16.3.6)",
          "published_on": "2026-09-28",
          "quote": "16.1.6: noto-sans-v27-latin-regular.ttf. 16.2.0, 16.3.5, 16.3.6: Geist-Regular.ttf."
        }
      ]
    }
  ],
  "non_findings": [
    {
      "kind": "miss",
      "chargeable_miss": true,
      "miss_class": "no_severity_level",
      "charged_on": null,
      "summary": "Task 1(a): hand-rolled `router.refresh()` + `reset()` inside `startTransition`, which is exactly what the `retry` prop passed to every `error.tsx` since 16.2.0 does (as `unstable_retry`; stable as `retry` at 16.3.0). It volunteered \"a faint memory of a newer `unstable_retry`-style prop on error boundaries in a later 16.x, but I can't confirm it\" — the right name, undesignated. Working code; the scale has no level for 'superseded by a first-class API' (`next.js/v2` precedent). 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": "context",
      "summary": "DERIVABLE — task 1(b): `reset()` re-renders from the payload already held, nothing is requested, the query does not re-run and the error returns. Correct, and answered correctly by both below-floor controls in `next.js/v2` (`sonnet-5-v2-c`, `fable-5-v2-d`), so not reported as knowledge of anything in the band.",
      "api": "error.tsx retry prop",
      "introduced_in": "16.2.0",
      "chargeable_miss": false
    },
    {
      "kind": "miss",
      "chargeable_miss": true,
      "miss_class": "no_severity_level",
      "charged_on": null,
      "summary": "Task 2(a): \"Next.js has no public component-level error boundary\" — then parallel routes with a per-slot `error.tsx`, and a React class boundary as the alternative. `next/error` has exported one since 16.2.0 (`unstable_catchError`; `catchError` from 16.3.0). The denial is explicit, but the code it designates works, so under the `next.js/v2` precedent it is a miss with no severity level. Not charged.",
      "api": "catchError (next/error)",
      "introduced_in": "16.2.0",
      "why_not_a_finding": "Parallel routes with slot-level `error.tsx` isolate the widget on 16.3.6."
    },
    {
      "kind": "context",
      "summary": "DERIVABLE — task 2(b): Next's own boundaries rethrow `NEXT_REDIRECT`; a hand-rolled class boundary would swallow it unless it checks the digest. Correct; the hazard predates the band and both v2 controls answered it.",
      "api": "catchError (next/error)",
      "introduced_in": "16.2.0",
      "chargeable_miss": false
    },
    {
      "kind": "correct",
      "summary": "Task 4, ALL FOUR PARTS RIGHT under an explicit non-recognition: \"I don't recognise `transitionTypes` as a `Link` prop. It must be newer than my reliable knowledge. These are guesses\" — then (a) `addTransitionType('slide')` in the navigation Transition; (b) Pages Router ignores it; (c) no warning in either router, \"assuming `Link` pulls the prop out\"; (d) a dev-time prop error demanding an array. Every v2 draw (Opus 5 ×2, Sonnet 5, Fable 5) denied the prop and predicted the warning. Recorded as correct and NOT as recall of 16.2.0: the draw says it reasoned from the obvious design, and the prompt's (d) names the array. P2 FALSIFIED on this arm.",
      "api": "Link transitionTypes",
      "introduced_in": "16.2.0",
      "chargeable_miss": false
    },
    {
      "kind": "imprecision",
      "summary": "Task 5(a), the scored half: \"As far as I know, the image cache in `.next/cache/images` has no size limit by default ... The question implies a newer rule, perhaps a default based on a fraction of disk space calculated when the server starts. I can't describe that rule. Confidence: low that this is still current.\" The designated statement is LF25's stale belief (unbounded); the hedge names the right shape and timing, and 5(b)/(c) write the RIGHT key — `maximumDiskCacheSize: 1_000_000_000` and `maximumDiskCacheSize: 0` (\"a guess at the option name\"), both accepted by 16.3.6's `configSchema` (executed). Under the code-vs-claim rule a hedged prose claim beside a correct fix is an imprecision. P4 FALSIFIED on this arm: the right key was written.",
      "api": "images.maximumDiskCacheSize",
      "introduced_in": "16.1.7",
      "chargeable_miss": false
    },
    {
      "kind": "context",
      "summary": "VOID PROBE — task 6, scored for nobody as pre-registered (the 'default image configuration' wording beside a remote `src`). This draw read it as the allowlist being satisfied, designated 'optimized normally, slow first request', and then volunteered: \"I believe a later release added a cap on how large an upstream image can be (possibly `images.maximumResponseBody`, default around 50 MB) ... I lean towards the cap existing\" — the right key and figure for LF26 (16.1.5), hedged.",
      "api": "images.maximumResponseBody",
      "introduced_in": "16.1.5",
      "chargeable_miss": false
    },
    {
      "kind": "correct",
      "summary": "Task 7, the internal control (LF8, 16.0.0): \"It's encoded at **75**. From Next 16, `images.qualities` defaults to `[75]`, and the `quality` prop is snapped to the nearest allowed value\"; dated to 16.0, October 2025. Right on the behaviour (executed on 16.3.6: `q=90` becomes `q=75`) and on the release, so this arm's attribution answers are readable.",
      "api": "images.qualities",
      "introduced_in": "16.0.0",
      "chargeable_miss": false
    },
    {
      "kind": "correct",
      "summary": "Task 8: \"I don't know of a stable option to switch back to one request per link. If there is one, it's probably an experimental flag, something like `experimental: { prefetchInlining: true }` (I'm unsure of the name), which would bundle a route's segments into one response.\" The right key, the right namespace and the right mechanism (16.2.0; `configSchema` accepts it at 16.3.6, executed). No dead `clientSegmentCache` offered. P3 FALSIFIED — the prediction said no draw of four would name it. Its twin did not (below).",
      "api": "experimental.prefetchInlining",
      "introduced_in": "16.2.0",
      "chargeable_miss": false
    },
    {
      "kind": "context",
      "summary": "Task 9, attribution: both behaviours guessed at \"16.1.0, around December 2025\". True: the font default 16.2.0 (a minor), the disk-cache rule 16.1.7 (a patch, two days earlier). Neither reached; no patch named. P5 HELD. None of the eight draws on these bytes (four in `next.js/v2`, four here) named a patch release.",
      "chargeable_miss": false
    },
    {
      "kind": "context",
      "summary": "Task 10: recency not charged. The v1 S4 rule would reach it (knowledge stops at 16.0.0, below 16.2.0, the last minor before the stated cutoff), but no Claude Opus 5.5 or Claude Fable 5.1 run in the corpus carries an S4 recency finding and this battery did not pre-register one; the stated boundary is recorded above.",
      "chargeable_miss": false
    }
  ],
  "open_questions": [
    {
      "question": "This arm stated a boundary one minor BELOW its own ladder (16.0 vs 16.1.0) and then, in hedges, produced the right names for four band facts (unstable_retry, prefetchInlining, maximumDiskCacheSize, maximumResponseBody ~50 MB) — while missing the OG font outright. Is the prompt cueing the names (task 5's 'say when it is computed', task 8's 'accepting more duplicated data'), or is this recall below the subject's own confidence threshold? The twin produced two of the four. A name-free re-probe of prefetchInlining would separate them.",
      "status": "open"
    }
  ]
}