{
  "$schema": "../../schema/run.schema.json",
  "run_id": "better-auth--claude-opus-5-5--v9-b--2026-09-28",
  "supersedes": null,
  "replicate_of": "better-auth--claude-opus-5-5--v9-a--2026-09-28",
  "library": {
    "name": "better-auth",
    "ecosystem": "npm",
    "latest_version_at_test": "1.7.6",
    "latest_version_verified_on": "2026-09-28",
    "latest_version_note": "`data/better-auth/releases.json` (fetched 2026-09-27; `fetch-releases --check` at 06:01Z this session, 8 of 8 current, COMMITTED TREE) gives `latest_at_fetch` 1.7.6. v7 was graded against 1.7.3, so 1.7.6 was installed this session and every graded answer re-read in its shipped bytes before either draw was spawned (`prompts/better-auth.md` § v9): `freshSessionMiddleware` still anchors on `createdAt` with `freshAge !== 0` as the off switch, `resendStrategy` and `twoFactorPage` are still declared, and no freshness-anchor option exists."
  },
  "model": {
    "id": "claude-opus-5-5",
    "label": "Claude Opus 5.5",
    "vendor": "Anthropic",
    "self_reported_cutoff": "2026-06",
    "believed_latest_version": "1.4.x; 1.5 held as a number only",
    "believed_latest_quote_form": "draw",
    "knowledge_stops_at_version": "1.4.0",
    "knowledge_stops_on": "2025-11-22",
    "knowledge_stops_provenance": "stated",
    "knowledge_gap_starts_at_version": "1.5.0",
    "knowledge_gap_starts_on": "2026-03-01",
    "knowledge_gap_provenance": "stated",
    "cutoff_lag_months": 7,
    "invoked_as": "Agent tool, model alias \"opus\"; prompt sent verbatim from prompts/sent/better-auth-v7.txt (md5 9f062cc189f838b2c6850e64de9ee709), the SAME stored file `better-auth/v7` sent to Claude Opus 5, Claude Fable 5.1, Claude Sonnet 5 and Claude Haiku 4.5 on 2026-09-06. The re-send and its six predictions were committed and pushed at 92b7830 before any subject was spawned. Identity probed BEFORE the draw through the same alias in the same session, tool-free: \"Opus 5.5 (1M context), model ID `claude-opus-5-5[1m]`. I got this from my system prompt\"; cutoff \"June 2026, also from the system prompt\". Drawn concurrently with its twin. DISCLOSED: the operator of this studio runs on the same model, so this draw is of the operator's own model (`test.self_test`). The blind TWIN of `v9-a`; charges nothing by pre-registration.",
    "cutoff_basis": "Self-reported and affirming at direct (b): \"My stated training cutoff is June 2026. My detailed knowledge of better-auth gets thin well before that, from about late 2025.\" A density qualification, not a substitute date.",
    "believed_latest_quote": "\"The latest version I know of is 1.4.x, and I believe a 1.5 line exists. The most recent release whose contents I can describe is 1.4, from about November 2025.\" … \"The first release I know only as a version number is 1.5, which I think came out in early 2026.\"",
    "boundary_note": "Equal to `v9-a` and to the ladder `better-auth/v8`. P5 HELD. Its closing caveat names the pre-1.6.0 implementation exactly (\"At least some earlier code versions measured from `updatedAt || createdAt`. If your version does that, Task 1 flips to yes\") without dating the change — the docs-vs-code knowledge `v7-b` and `v7-c` also had, not a description of 1.6.0."
  },
  "test": {
    "date": "2026-09-28",
    "battery": "better-auth/v9-b",
    "battery_spec": "prompts/better-auth.md",
    "prompt_file": "prompts/sent/better-auth-v7.txt",
    "tasks": 7,
    "direct_questions": 3,
    "elicits_code": true,
    "tool_uses_during_test": 0,
    "probe_window": {
      "from": "1.5.6",
      "to": "1.7.6"
    },
    "self_test": true,
    "saturated": false,
    "status": "open",
    "retested_on": null
  },
  "sources": [
    "https://registry.npmjs.org/better-auth",
    "https://registry.npmjs.org/better-auth/-/better-auth-1.7.6.tgz",
    "https://registry.npmjs.org/better-auth/-/better-auth-0.8.8.tgz",
    "https://registry.npmjs.org/better-auth/-/better-auth-1.0.0.tgz",
    "https://github.com/better-auth/better-auth/releases/tag/v1.6.0"
  ],
  "findings": [],
  "non_findings": [
    {
      "kind": "correct",
      "summary": "TASK 1: \"No\", agreeing with its twin (P6 HELD). Correct at 1.6.0+, not credited as recall for the same reason as `v9-a`: every control on these bytes answered \"No\".",
      "api": "session.freshAge (measured from session.createdAt)",
      "introduced_in": "1.6.0"
    },
    {
      "kind": "correct",
      "summary": "TASK 5: (a) `createdAt`, (b) `session: { freshAge: 0 }`. Both correct at 1.7.6.",
      "api": "session.freshAge (measured from session.createdAt)",
      "introduced_in": "1.6.0"
    },
    {
      "kind": "miss",
      "chargeable_miss": true,
      "miss_class": "non_charging_arm",
      "charged_on": "better-auth--claude-opus-5-5--v9-a--2026-09-28",
      "summary": "TASK 2, reproducing its twin's denial: \"No\", with an option list that is the 1.5.0 list (\"`sendVerificationOTP`, `otpLength`, `expiresIn`, `allowedAttempts`, `storeOTP`, `generateOTP`, `disableSignUp`, `sendVerificationOnSignUp` and `overrideDefaultEmailVerification`\"). Its workaround is more invasive than `v9-a`'s: `storeOTP: \"encrypted\"`, then an `async generateOTP(…, ctx)` that reads the verification row through `ctx.context.internalAdapter.findVerificationValue`, splits the stored value on `:` and decrypts it with `symmetricDecrypt` — internal details the draw itself flags. The `async` signature is the same TS2322 `v9-a` hits at 1.7.6; the rest was not executed. The real option is `resendStrategy: \"reuse\"` (1.5.6). Twin — charges nothing.",
      "api": "emailOTP({ resendStrategy })",
      "introduced_in": "1.5.6"
    },
    {
      "kind": "miss",
      "chargeable_miss": true,
      "miss_class": "non_charging_arm",
      "charged_on": "better-auth--claude-opus-5-5--v9-a--2026-09-28",
      "summary": "TASK 6, reproducing its twin: \"No\", and \"Older versions had a `twoFactorPage` string option. The current client plugin takes an `onTwoFactorRedirect` callback instead\" — correct history (0.x → 1.0.0), stale present tense (the string is back from 1.5.6). The callback client compiles at 1.7.6. Twin — charges nothing.",
      "api": "twoFactorClient({ twoFactorPage })",
      "introduced_in": "1.5.6"
    },
    {
      "kind": "correct",
      "summary": "TASK 3, the pre-registered control: \"No\", correctly — no option chooses the freshness anchor at any release, and none at 1.7.6 (`freshAgeFrom`/`freshAgeBasis`/`freshFrom` absent across `dist`). P3 HELD on both draws.",
      "api": "session.freshAge anchor option (does not exist)",
      "introduced_in": null
    },
    {
      "kind": "correct",
      "summary": "TASK 4, the floor: `customSession` on the server and `customSessionClient<typeof auth>()` on the client — the 1.0.0 answer, correct. P4 HELD on both draws.",
      "api": "customSession / customSessionClient",
      "introduced_in": "1.0.0"
    },
    {
      "kind": "context",
      "summary": "TASK 7, attribution anchor (belief data, never scored): stateless / database-less sessions dated to 1.4, \"around late 2025 (roughly November)\" — correct (1.4.0, 2025-11-22). P6-of-v7's drift did not appear here.",
      "api": "stateless sessions (cookie-cache JWT/JWE, no database)",
      "introduced_in": "1.4.0"
    }
  ],
  "summary": "Blind twin of `v9-a`, and it agreed on every verdict: task 1 \"No\", task 5 `createdAt`, and the same two denials of the 1.5.6 options (`resendStrategy`, `twoFactorPage`), recorded as chargeable misses that charge nothing. It gave the same correct 0.x history for `twoFactorPage` and the same 1.4.0 boundary."
}