{ "$schema": "../../schema/run.schema.json", "run_id": "tailwindcss--claude-opus-5-5--v5-a--2026-09-27", "supersedes": null, "replicate_of": null, "library": { "name": "tailwindcss", "ecosystem": "npm", "latest_version_at_test": "4.3.3", "latest_version_verified_on": "2026-09-27", "latest_version_note": "The registry document read 2026-09-27 gives dist-tag `latest` 4.3.3 (2026-07-16) and no 4.4, so \"the current stable release\" the prompt names is the same release `tailwindcss/v3` was graded against on 2026-09-06. Every workaround this draw offered that v3's arms had not was compiled this session with the real Tailwind engine against installed 4.2.0, 4.3.0 and 4.3.3: `[zoom:0.5]`, `scale-50`, `[&::-webkit-scrollbar-corner]:bg-slate-100`, the `@utility scrollbar-slim` block, and the task 4 stylesheet (nested `@variant hover { @variant focus {…} }` plus three single-variant blocks). All compile at all three. `scrollbar-gutter-stable`, `zoom-50`, `tab-4` and `@container-size` emit nothing at 4.2.0 and the expected declaration at 4.3.0 and 4.3.3; `@variant hover:focus` throws `Cannot use @variant with unknown variant: hover:focus` at 4.2.0 and compiles at 4.3.0." }, "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/tailwindcss-v3.txt (3,739 bytes, md5 f44aeae2d3a5b4998eec53b3b3aa93d3) — the SAME stored file `tailwindcss/v3` sent to Claude Fable 5.1, Claude Opus 5 and Claude Sonnet 5 on 2026-09-06. The re-send and its predictions were committed and pushed at 6c4b785 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). This comes from my system prompt\", \"`claude-opus-5-5[1m]`. This also comes from my system prompt\", \"June 2026. This comes from my system prompt ... not from my own knowledge\". Nominated in the spec as the CHARGING arm of the Opus 5.5 pair, and it charges. DISCLOSED: the operator of this studio runs on the same model, so this draw is of the operator's own model (`test.self_test`).", "self_reported_cutoff": "2026-06", "cutoff_basis": "Self-reported and AFFIRMING, qualifying only the density of recall: \"My training cutoff is listed as June 2026, but my detailed knowledge of Tailwind thins out around v4.1.x (mid-to-late 2025).\" and at direct (b): \"My training cutoff is stated as June 2026. My reliable knowledge of Tailwind releases ends around the second half of 2025.\" Under HARNESS.md § *A density self-assessment is not a stated cutoff* the qualification does not disqualify the arm. 4.3.0 shipped 2026-05-08, roughly a month below the stated cutoff — the same gap as Fable 5.1's `v3-a`.", "believed_latest_version": "4.1.x", "believed_latest_quote": "\"The latest version I know of is v4.1.x (a patch release of 4.1, perhaps 4.1.1x). I have a faint sense that a v4.2 exists, but I can't describe it. The most recent release whose contents I can actually describe is v4.1, from about April 2025.\" … \"The first release I know only as a version number is **v4.2**. I believe it exists, but I can't describe what's in it.\"", "believed_latest_quote_form": "draw", "knowledge_stops_at_version": "4.1.0", "knowledge_stops_on": "2025-04-01", "knowledge_stops_provenance": "stated", "knowledge_gap_starts_at_version": "4.2.0", "knowledge_gap_starts_on": "2026-02-18", "knowledge_gap_provenance": "stated", "boundary_note": "Identical to this subject's own ladder `tailwindcss/v4`, drawn about six hours earlier the same day on a different instrument (4.1.0 described, 4.2.0 held as a number only), and to its blind twin `v5-b`. Its 4.1 description (text-shadow-*, mask-*, coloured drop-shadow, wrap-break-word/wrap-anywhere, safe alignment, pointer-* variants, noscript, user-valid/user-invalid, inverted-colors, details-content, `@source not`, `@source inline()`) is the same list the ladder gave and the ladder verified in 4.1.0's shipped bytes. No 4.2.0 or 4.3.0 content appears anywhere in the reply, so the stated end is not equivocal.", "cutoff_lag_months": 14 }, "test": { "date": "2026-09-27", "battery": "tailwindcss/v5-a", "battery_spec": "prompts/tailwindcss.md", "prompt_file": "prompts/sent/tailwindcss-v3.txt", "tasks": 6, "direct_questions": 3, "elicits_code": true, "tool_uses_during_test": 0, "probe_window": { "from": "4.3.0", "to": "4.3.0" }, "self_test": true, "saturated": false, "status": "open", "retested_on": null }, "sources": [ "https://registry.npmjs.org/tailwindcss", "https://github.com/tailwindlabs/tailwindcss/releases/tag/v4.3.0", "https://registry.npmjs.org/tailwindcss/-/tailwindcss-4.3.0.tgz", "https://registry.npmjs.org/tailwindcss/-/tailwindcss-4.2.0.tgz", "https://registry.npmjs.org/tailwindcss/-/tailwindcss-4.3.3.tgz" ], "findings": [ { "id": "F1", "severity": "S2", "severity_label": "silently-wrong", "title": "Denies Tailwind ships scrollbar utilities, says the class names belong to a plugin, and rejects working markup that uses them", "api": "scrollbar-auto / scrollbar-thin / scrollbar-none / scrollbar-thumb-* / scrollbar-track-* / scrollbar-gutter-*", "change_kind": "added", "introduced_in": "4.3.0", "introduced_on": "2026-05-08", "chargeable": true, "chargeable_note": "4.3.0 shipped 2026-05-08; this draw states a June 2026 cutoff, so the release precedes it by about a month.", "model_belief": "Task 1(a), one word: \"No\". Then: \"As far as I know, Tailwind core has never shipped `scrollbar-width`, `scrollbar-color` or `scrollbar-gutter` utilities. Names like `scrollbar-thin` and `scrollbar-thumb-*` come from the community `tailwind-scrollbar` plugin.\" On task 3, reviewing markup that uses them: \"`scrollbar-thin`, `scrollbar-thumb-slate-500`, `scrollbar-track-slate-100`, `scrollbar-gutter-stable`: I don't think these are core. They'd only work with the plugin. Replace them with the arbitrary properties from Task 1, or an `@utility`.\"", "wrong_code": "\n
", "correct_code": "
", "impact": "The charge is the REVIEW direction, as on Fable 5.1's `v3-a` F1. The arbitrary-property markup and the `@utility scrollbar-slim` block this draw shipped in task 1 both compile at 4.2.0, 4.3.0 and 4.3.3 and emit the same three declarations, so a reader who takes only task 1 loses brevity and nothing else — S3 under the workaround rule. What lifts it to S2 is task 3: shown working markup, the draw tells its author that four classes only work with a plugin the project does not have and should be replaced. All four compile at 4.3.0 and 4.3.3. A reviewer acting on that deletes correct code.", "citations": [ { "url": "https://github.com/tailwindlabs/tailwindcss/releases/tag/v4.3.0", "title": "tailwindcss v4.3.0 release notes — Added", "published_on": "2026-05-08", "quote": "Add `scrollbar-{auto,thin,none}` utilities for `scrollbar-width`, and `scrollbar-thumb-*` / `scrollbar-track-*` color utilities for `scrollbar-color`" }, { "url": "https://github.com/tailwindlabs/tailwindcss/releases/tag/v4.3.0", "title": "tailwindcss v4.3.0 release notes — Added", "published_on": "2026-05-08", "quote": "Add `scrollbar-gutter-*` utilities" }, { "url": "https://registry.npmjs.org/tailwindcss/-/tailwindcss-4.3.3.tgz", "title": "tailwindcss 4.3.3, shipped package (the current release) — `scrollbar-gutter-stable` compiles to `scrollbar-gutter: stable`; the scrollbar family compiles as recorded on LF31." }, { "url": "https://registry.npmjs.org/tailwindcss/-/tailwindcss-4.2.0.tgz", "title": "tailwindcss 4.2.0, shipped package — `scrollbar-gutter-stable` compiles to nothing, compiled this session." } ], "scope_note": "The denial was hedged (\"I'm fairly but not fully sure this still holds for the newest v4 releases\"; \"I don't think these are core\"). Under HARNESS.md § *A hedge is a self-placement, not a grade on the content* the hedge is recorded and does not soften a verdict-first \"No\" or a review that tells the author to replace the classes. The draw did NOT tell the reader to install the plugin, so the plugin-substitute route to S2 does not apply; S2 rests on the review alone. PARTIAL DERIVABILITY: the names were produced from below the floor by Sonnet 5 (`v3-d`, the three colour/width names) and now by Claude Haiku 4.5 (`v5-c`, all four including `scrollbar-gutter-stable`), so no pass on these names anywhere is read as recall; a derivable outcome kills a pass, not a failure (JOURNAL/031). The draw's Chromium 121 claim (that setting `scrollbar-width`/`scrollbar-color` makes Chromium ignore `::-webkit-scrollbar*`) was NOT verified and nothing here rests on it." }, { "id": "F2", "severity": "S2", "severity_label": "silently-wrong", "title": "Rejects `zoom-50` and `tab-4` as not core, in a review of markup where both compile", "api": "zoom-* / tab-*", "change_kind": "added", "introduced_in": "4.3.0", "introduced_on": "2026-05-08", "chargeable": true, "chargeable_note": "4.3.0 (2026-05-08) precedes this draw's stated 2026-06 cutoff.", "model_belief": "Task 3: \"`tab-4`: I don't think this is core. Use `[tab-size:4]`.\" and \"`zoom-50`: I don't think this is core. Use `[zoom:0.5]`, or `scale-50` if a transform is acceptable (it doesn't affect layout the way `zoom` does).\"", "wrong_code": "
…
\n
…
", "correct_code": "
…
\n
…
", "impact": "Two working classes called out as inert in review. Both replacements compile at 4.2.0, 4.3.0 and 4.3.3 (`[tab-size:4]` -> `tab-size: 4`, `[zoom:0.5]` -> `zoom: 0.5`, the same computed value as `zoom-50`'s `zoom: 50%`), so the page keeps working; the cost is deleted correct code and a reviewer's stated confidence about two utilities that exist. This draw, unlike Fable 5.1's `v3-a`, flags that `scale-50` is not a drop-in for `zoom` itself, so the non-equivalence risk `v3-a` F3 recorded is mitigated in the reply. Across the four live-subject draws on these bytes (Fable 5.1 `v3-a`/`v3-b`, Opus 5.5 `v5-a`/`v5-b`), three rejected `tab-4` and one — Fable 5.1's charging arm — accepted it.", "citations": [ { "url": "https://github.com/tailwindlabs/tailwindcss/releases/tag/v4.3.0", "title": "tailwindcss v4.3.0 release notes — Added", "published_on": "2026-05-08", "quote": "Add `zoom-*` utilities" }, { "url": "https://github.com/tailwindlabs/tailwindcss/releases/tag/v4.3.0", "title": "tailwindcss v4.3.0 release notes — Added", "published_on": "2026-05-08", "quote": "Add `tab-*` utilities" }, { "url": "https://registry.npmjs.org/tailwindcss/-/tailwindcss-4.3.3.tgz", "title": "tailwindcss 4.3.3, shipped package — `zoom-50` compiles to `zoom: 50%` and `tab-4` to `tab-size: 4`, compiled this session." }, { "url": "https://registry.npmjs.org/tailwindcss/-/tailwindcss-4.2.0.tgz", "title": "tailwindcss 4.2.0, shipped package — `zoom-50` and `tab-4` compile to nothing, compiled this session." } ], "scope_note": "One finding for both classes because one fact (LF32) covers both and the verdict on each is the same sentence. The hedge (\"I don't think\") is recorded and does not soften the review verdict. `tab-*` is DERIVABLE (Sonnet 5 `v3-d` gave the scale from sixteen months below); `zoom-*` is not — no control in either battery has produced it, Haiku 4.5 `v5-c` included." }, { "id": "F3", "severity": "S3", "severity_label": "deprecated", "title": "Denies `@variant` accepts a stacked or comma-separated variant, nests the AND and writes the OR block out three times", "api": "@variant (stacked and compound variants)", "change_kind": "added", "introduced_in": "4.3.0", "introduced_on": "2026-05-08", "chargeable": true, "chargeable_note": "4.3.0 (2026-05-08) precedes this draw's stated 2026-06 cutoff.", "model_belief": "Task 4(a), one word: \"No\". Then: \"I believe `@variant` takes one variant name per use. You get \\\"and\\\" by nesting. For \\\"or\\\" you repeat the block or write plain selectors. I'm not certain that the stacked form `@variant hover:focus` is unsupported.\"", "wrong_code": ".btn {\n @variant hover {\n @variant focus {\n outline: 2px solid var(--color-slate-500);\n }\n }\n\n @variant hover { background: var(--color-slate-100); }\n @variant focus { background: var(--color-slate-100); }\n @variant active { background: var(--color-slate-100); }\n}", "correct_code": ".btn {\n @variant hover:focus {\n outline: 2px solid var(--color-slate-500);\n }\n\n @variant hover, focus, active {\n background: var(--color-slate-100);\n }\n}", "impact": "S3, for LF34's stated reason. The draw's whole stylesheet was compiled at 4.2.0, 4.3.0 and 4.3.3 and compiles at all three: the nested AND produces what the stacked form produces, and the OR is working CSS written three times. Nothing breaks; the reader is told a capability of the current release does not exist and writes more to get the same output. The draw's own reason for preferring `@variant hover` over `&:hover` — that the variant wraps the rule in `@media (hover: hover)` — is correct, verified in the compiled output.", "citations": [ { "url": "https://github.com/tailwindlabs/tailwindcss/releases/tag/v4.3.0", "title": "tailwindcss v4.3.0 release notes — Added", "published_on": "2026-05-08", "quote": "Allow using `@variant` with stacked variants (e.g. `@variant hover:focus { … }`)" }, { "url": "https://github.com/tailwindlabs/tailwindcss/releases/tag/v4.3.0", "title": "tailwindcss v4.3.0 release notes — Added", "published_on": "2026-05-08", "quote": "Allow using `@variant` with compound variants (e.g. `@variant hover, focus { … }`)" }, { "url": "https://registry.npmjs.org/tailwindcss/-/tailwindcss-4.3.3.tgz", "title": "tailwindcss 4.3.3, shipped package — `@variant hover:focus { … }` compiles, compiled this session." }, { "url": "https://registry.npmjs.org/tailwindcss/-/tailwindcss-4.2.0.tgz", "title": "tailwindcss 4.2.0, shipped package — `@variant hover:focus { … }` throws `Cannot use @variant with unknown variant: hover:focus`; this draw's nested and single-variant blocks compile, compiled this session." } ], "scope_note": "THIS PROBE IS DERIVABLE: Claude Sonnet 5 answered \"Yes\" and wrote both forms from sixteen months below (`v3-d`). A derivable outcome kills a pass, not a failure (JOURNAL/031), so the charge stands. P3 of the v5 spec predicted exactly this answer and it held; the hedge (\"I'm not certain that the stacked form ... is unsupported\") is recorded and does not soften the verdict-first \"No\"." } ], "non_findings": [ { "kind": "context", "summary": "TASK 3, `@container-size`: NOT CHARGED, and the line between this and Fable 5.1's `v3-a` F2 is drawn here on purpose. This draw did not reject the class: \"I'm unsure. v4 has `@container` (inline-size) and `@container-normal`. I have a vague memory that a size variant was added, but I can't confirm it. If it's wrong, use `[container-type:size]`.\" That is an abstention leaning toward the right answer, not a verdict; `v3-a` was charged for \"not a core utility as far as I know\", which is one. A reviewer acting on this reply keeps the class and checks it. `@container-normal` exists at 4.2.0 and 4.3.x as stated. The probe is DERIVABLE in any case (Opus 5, `v3-c`), so nothing here could have been read as recall.", "api": "@container-size", "introduced_in": "4.3.0" }, { "kind": "correct", "summary": "TASK 2, the internal guessing control: no invention of `scrollbar-corner-*`. \"The framework doesn't cover this. There are no corner utilities, and I don't think there's a standard CSS property for it either. The only hook is `::-webkit-scrollbar-corner`\", shipped as the arbitrary variant `[&::-webkit-scrollbar-corner]:bg-slate-100`, which compiles at 4.2.0, 4.3.0 and 4.3.3. Its Chromium 121 precedence caveat is the same one every v3 arm gave; not verified in a browser.", "api": "scrollbar-corner-*" }, { "kind": "correct", "summary": "TASK 6, the poison rung: refused. \"I don't know. I'm not aware of any release that added `overflow-anchor` utilities. If one exists, it's after my knowledge ends.\" No `overflow-anchor` utility exists at any release through 4.3.3.", "api": "overflow-anchor" }, { "kind": "context", "summary": "TASK 5, attribution: \"I don't know of any change. As far as I know, core has never covered scrollbar styling.\" Not read as a boundary datum — the arm does not hold the capability, and an attribution question about a behaviour the subject does not hold measures nothing independent (JOURNAL/030)." }, { "kind": "context", "summary": "THE PAIR AGREED ON EVERY PROBE. Both Opus 5.5 draws answered \"No\" to 1(a) and 4(a), rejected the same five task 3 classes (four scrollbar, `tab-4`, `zoom-50`), abstained on `@container-size`, invented nothing on task 2, refused the poison rung and placed the boundary at 4.1.0 / 4.2. Fable 5.1's pair on the same bytes split on `tab-4`. Two live subjects, four draws, one shape: denial in the offer direction and rejection in the review direction on every 4.3.0 class but the one each Opus 5.5 draw said it half-remembered." }, { "kind": "context", "summary": "BOUNDARY, three placements on one day and two instruments: 4.1.0 described, 4.2 held as a number only, stated cutoff 2026-06, fourteen-month lag — identical to this subject's ladder `tailwindcss/v4` and to its twin `v5-b`, and identical to both Fable 5.1 draws of `v3`. P6 held. A different battery is not a different boundary (JOURNAL/030); this is a replication of the ladder's reading on a code battery, not a new measurement to re-charge." } ], "open_questions": [], "summary": "Claude Opus 5.5's first code-battery findings on tailwindcss, from a byte-identical re-send of the prompt Fable 5.1 was charged on three weeks ago. tailwindcss 4.3.0 shipped about a month below this subject's stated June 2026 cutoff. Three charges: two S2 in the review direction — the scrollbar family, and `zoom-50` plus `tab-4`, each called not-core in a pull request where every class compiles — and one S3 denial that `@variant` takes a stacked or comma-separated variant. Every workaround the draw offered was compiled against installed 4.2.0, 4.3.0 and 4.3.3 and every one works, so the charges rest on the denials and the rejections, never on the code. One 4.3.0 class was not charged: on `@container-size` the draw said it had a vague memory the utility was added and could not confirm it, which is an abstention and not the rejection Fable 5.1 was charged for. Guessing control clean, poison rung refused, and its blind twin agreed on every probe. Boundary 4.1.0, the same as this subject's own ladder drawn earlier the same day." }