{
  "$schema": "../../schema/run.schema.json",
  "run_id": "better-auth--claude-opus-5--v4-c--2026-09-03",
  "supersedes": null,
  "replicate_of": null,
  "library": {
    "name": "better-auth",
    "ecosystem": "npm",
    "latest_version_at_test": "1.7.2",
    "latest_version_verified_on": "2026-09-03",
    "latest_version_note": "Re-confirmed this session against https://registry.npmjs.org/better-auth (`npm view better-auth version` -> 1.7.2). The probe window is a single release, 1.3.0 (2025-07-19); nothing this battery reads depends on the current release."
  },
  "model": {
    "id": "claude-opus-5",
    "label": "Claude Opus 5",
    "vendor": "Anthropic",
    "invoked_as": "Agent tool, model override 'opus', no tools available to the subject",
    "self_reported_cutoff": "2026-05",
    "cutoff_basis": "Stated with an explicit caveat about self-report: \"I am told my cutoff is May 2026. I should be straightforward that models are unreliable narrators about their own cutoffs.\" Matches the value this subject has stated on every prior better-auth battery and on the boundary rollup.",
    "believed_latest_version": "1.3.x",
    "believed_latest_quote": "\"Latest version I have any impression of: the 1.3.x line, which I associate with roughly mid-2025. I do not have a confident belief about whether 1.4 or 2.0 exists.\"",
    "knowledge_stops_at_version": "1.2.0",
    "knowledge_stops_on": "2025-03-01",
    "knowledge_gap_starts_at_version": "1.3.0",
    "knowledge_gap_starts_on": "2025-07-19",
    "cutoff_lag_months": 22
  },
  "test": {
    "date": "2026-09-03",
    "battery": "better-auth/v4-c",
    "battery_spec": "prompts/better-auth.md",
    "prompt_file": "prompts/sent/better-auth-v4.txt",
    "tasks": 3,
    "direct_questions": 4,
    "tool_uses_during_test": 0,
    "probe_window": {
      "from": "1.3.0",
      "to": "1.3.0"
    },
    "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-1.2.7.tgz",
    "https://registry.npmjs.org/better-auth/-/better-auth-1.2.12.tgz",
    "https://registry.npmjs.org/better-auth/-/better-auth-1.3.0.tgz",
    "https://registry.npmjs.org/better-auth/-/better-auth-1.5.0.tgz",
    "https://registry.npmjs.org/better-auth/-/better-auth-1.7.2.tgz",
    "https://github.com/better-auth/better-auth/releases/tag/v1.3.0"
  ],
  "findings": [],
  "non_findings": [
    {
      "kind": "miss",
      "summary": "Task 1, the same-scheme sibling control, and the first time in three uses of this instrument that a draw has INVENTED the sibling. Asked verdict-first whether the phone-number plugin takes a storage option, it answered \"Yes. I believe the phone-number plugin takes a `storeOTP` option that controls how the code is persisted, with `\"hashed\"` among its values\" at \"~70%\" confidence, and then shipped it inside a `phoneNumber({ ... })` config as \"the security-review fix\". `phoneNumber({ storeOTP })` exists at no release: it is a TS2353 error under `tsc --strict` at 1.3.0, 1.5.0 and 1.7.2, in the same file where the four real options type-check clean. `PhoneNumberOptions` at 1.7.2 contains no storage or hashing field of any name. The draw did tell the reader to check the installed types first, which is the mitigation, but the verdict-first answer was yes and the shipped code does not compile.",
      "api": "phoneNumber storeOTP (does not exist)",
      "introduced_in": null,
      "chargeable_miss": true,
      "miss_class": "probe_class",
      "charged_on": null,
      "why_not_a_finding": "The battery's pre-registration, committed before any subject was spawned, declares task 1 a control from which no finding may be charged in either direction. Reading the results and then promoting the control to a scoring probe because it produced something chargeable is selecting on outcome — the error JOURNAL/044 named for arms, applying here to a task. Counted in the method page's undercount total, and the battery that would charge it is queued in BACKLOG.md."
    },
    {
      "kind": "correct",
      "summary": "Task 2, the target probe: named both options with their correct value unions, including the asymmetry between them. `emailOTP` was given as `storeOTP: { hash: async (otp) => ... }` and `magicLink` as `storeToken: { type: \"custom-hasher\", hash }` — and that is exactly right: the shipped magic-link form carries a `type: \"custom-hasher\"` discriminant and the shipped email-OTP form does not. It also recalled the encrypted mode and why it exists (\"encryption exists because some flows need to read the code back, which hashing forecloses\"); `storeOTP` does accept `\"encrypted\"` and an `{ encrypt, decrypt }` pair, and `storeToken` does not.",
      "api": "magicLink storeToken / emailOTP storeOTP",
      "introduced_in": "1.3.0",
      "chargeable_miss": false
    },
    {
      "kind": "correct",
      "summary": "Recalled the library's internal verification-row identifier format unprompted: \"the row is found by an identifier derived from the email address (something like `sign-in-otp-user@example.com`; the exact prefix is version-specific)\". Executed against an installed 1.3.0, the row written by `sendVerificationOTP` for a sign-in has identifier `sign-in-otp-a@example.com`. The format is exact, including the hyphenation and the position of the address.",
      "api": "email-OTP verification identifier format",
      "introduced_in": null
    },
    {
      "kind": "context",
      "summary": "The invention on task 1 and the precision on task 2 have to be reported together, because they cut against each other and the battery pre-registered how to read only one of them. The stated reading was that an invention marks the arm as running the naming scheme, which makes its target pass buy nothing (JOURNAL/035). That reading is strained here: a draw running a scheme would not also get the asymmetric discriminant right — `{ type: 'custom-hasher' }` on magic-link, bare `{ hash }` on email-OTP — nor reproduce an internal identifier string. What this draw looks like is a subject with real recall of the 1.3.0 option family that over-generalised it by one plugin. The sibling control was built to separate recall from derivation; on this arm it has instead found a third thing, and that is a result about the instrument.",
      "api": null,
      "introduced_in": null
    },
    {
      "kind": "miss",
      "summary": "Version attribution, direct question (d)(i)/(ii): placed the per-plugin hashing options in the 1.2.x line — \"Best estimate, marked as an estimate: somewhere in the 1.2.x line, plausibly around 1.2.9/1.2.10, mid-2025\" for email-OTP, and the same 1.2.x window for magic-link. They shipped in **1.3.0** (2025-07-19). `storeOTP` and `storeToken` appear nowhere in the published `dist` of `better-auth@1.2.7` or `better-auth@1.2.12` — 1.2.12 being the last stable 1.2.x — and appear in five files of 1.3.0's. The subject demonstrated it holds the capability and then dated it one minor low, which is the case HARNESS.md's attribution rule says is readable. This draw's attribution boundary (1.2.0 / 1.3.0) is identical to the same subject's reading on `better-auth/v3-a` and `v3-b`, so the misdating is not this battery moving the boundary.",
      "api": "magicLink storeToken / emailOTP storeOTP",
      "introduced_in": "1.3.0",
      "chargeable_miss": false
    },
    {
      "kind": "miss",
      "summary": "Direct question (d)(iii), the two-factor OTP option: declined rather than denied — \"Cannot place. I do not have a clear memory of a hashing option on the two-factor plugin's OTP path... Check the `twoFactor({ otpOptions: { ... } })` type directly — that is where it would live if it exists.\" The option does exist there, at 1.3.0. Recorded as a miss but NOT as a chargeable miss: the draw declined to place it and pointed at the exact type path, which is the behaviour the \"cannot place\" instruction asks for, and is materially different from the outright denials three other draws gave on the same question.",
      "api": "twoFactor otpOptions.storeOTP",
      "introduced_in": "1.3.0",
      "chargeable_miss": false
    },
    {
      "kind": "correct",
      "summary": "Floor probe (task 3) passed: named the `customSession` plugin, spread `user` and `session` back out of the callback, and added the companion `customSessionClient` on the client for type inference. The run is readable.",
      "api": "customSession",
      "introduced_in": "1.0.0"
    }
  ],
  "open_questions": [
    {
      "question": "Both Opus 5 draws claim that `session.cookieCache` and the `customSession` plugin do not compose cleanly — that a cached read can return a response missing the custom field or a stale one, and that the behaviour has moved across versions. Neither draw would state which versions. Not verified against any installed release this session.",
      "status": "open"
    }
  ],
  "summary": "The charging Opus 5 arm passed the target probe and failed the control. It named `storeOTP` and `storeToken` with their correct value unions — including the asymmetry that only magic-link's custom form carries a `type: \"custom-hasher\"` discriminant — and reproduced better-auth's internal verification identifier format (`sign-in-otp-<email>`) from memory. Then, on the sibling control, it answered yes to an option that exists at no release and shipped `phoneNumber({ storeOTP: ... })` as the fix. That invention is the first break of the same-scheme-sibling control in three uses, and it is not charged: the pre-registration made task 1 a control, and a task cannot be re-designated after its results are read. It dated the real options to 1.2.9/1.2.10; they shipped in 1.3.0."
}