diff --git a/src/prototypes/morelike-playground/EditAttributionLine.vue b/src/prototypes/morelike-playground/EditAttributionLine.vue
new file mode 100644
index 0000000..96fed26
--- /dev/null
+++ b/src/prototypes/morelike-playground/EditAttributionLine.vue
@@ -0,0 +1,48 @@
+<script setup lang="ts">
+import { computed } from 'vue'
+
+const props = defineProps<{
+  timestamp: string
+  author?: string
+}>()
+
+const when = computed(() => formatRelativeEdit(props.timestamp))
+const who = computed(() => props.author?.trim() ?? '')
+const show = computed(() => Boolean(when.value || who.value))
+
+function capitalizeFirstLetter(text: string): string {
+  if (!text.length) return text
+  return text.charAt(0).toLocaleUpperCase() + text.slice(1)
+}
+
+function formatRelativeEdit(iso: string): string {
+  if (!iso) return ''
+  const date = new Date(iso)
+  if (Number.isNaN(date.getTime())) return ''
+
+  const diffSec = Math.round((date.getTime() - Date.now()) / 1000)
+  const rtf = new Intl.RelativeTimeFormat(undefined, { numeric: 'auto' })
+  const abs = Math.abs(diffSec)
+
+  let relative = ''
+  if (abs < 60) relative = rtf.format(diffSec, 'second')
+  else if (abs < 3600) relative = rtf.format(Math.round(diffSec / 60), 'minute')
+  else if (abs < 86400) relative = rtf.format(Math.round(diffSec / 3600), 'hour')
+  else if (abs < 2592000) relative = rtf.format(Math.round(diffSec / 86400), 'day')
+  else if (abs < 31536000) relative = rtf.format(Math.round(diffSec / 2592000), 'month')
+  else relative = rtf.format(Math.round(diffSec / 31536000), 'year')
+
+  return capitalizeFirstLetter(relative)
+}
+</script>
+
+<template>
+  <span v-if="show" class="morelike-playground__edit-meta">
+    <template v-if="when && who">
+      {{ when }} by <span class="morelike-playground__editor">{{ who }}</span>
+    </template>
+    <template v-else-if="when">{{ when }}</template>
+    <template v-else><span class="morelike-playground__editor">{{ who }}</span></template>
+  </span>
+</template>
+
diff --git a/src/prototypes/morelike-playground/fetchMorelike.ts b/src/prototypes/morelike-playground/fetchMorelike.ts
new file mode 100644
index 0000000..1118936
--- /dev/null
+++ b/src/prototypes/morelike-playground/fetchMorelike.ts
@@ -0,0 +1,458 @@
+import { wikimediaApiFetchHeaders } from '@/config'
+
+import {
+  resolveMltParams,
+  type MorelikeMltCustomSettings,
+  type MorelikeMltPreset,
+  type MorelikeSortOrder,
+} from './morelikeMlt'
+
+const WIKI_HOST = 'en.wikipedia.org'
+const API_URL = `https://${WIKI_HOST}/w/api.php`
+
+export interface MorelikeSearchHit {
+  title: string
+  description: string
+  timestamp: string
+  pageUrl: string
+  revisionAuthor?: string
+  revisionComment?: string
+  revisionContent?: string
+  thumbnail?: {
+    url: string
+    width: number
+    height: number
+  }
+}
+
+interface GeneratorRevision {
+  timestamp?: string
+  user?: string
+  comment?: string
+  slots?: {
+    main?: {
+      content?: string
+    }
+  }
+}
+
+interface GeneratorPage {
+  title: string
+  index?: number
+  description?: string
+  thumbnail?: {
+    source: string
+    width: number
+    height: number
+  }
+  revisions?: GeneratorRevision[]
+}
+
+interface GeneratorSearchResponse {
+  error?: {
+    code?: string
+    info?: string
+  }
+  query?: {
+    pages?: GeneratorPage[]
+  }
+}
+
+export class MorelikeFetchError extends Error {
+  constructor(
+    message: string,
+    public readonly code: 'aborted' | 'http' | 'empty',
+  ) {
+    super(message)
+    this.name = 'MorelikeFetchError'
+  }
+}
+
+/** Split seed input on newlines and commas; trim, dedupe, drop empties. */
+export function parseSeedTitles(raw: string): string[] {
+  const seen = new Set<string>()
+  const titles: string[] = []
+
+  for (const part of raw.split(/[\n,]+/)) {
+    const title = part.trim()
+    if (!title.length || seen.has(title)) continue
+    seen.add(title)
+    titles.push(title)
+  }
+
+  return titles
+}
+
+export function buildSrsearch(seedText: string): string | null {
+  const seeds = parseSeedTitles(seedText)
+  if (!seeds.length) return null
+
+  return `morelike:${seeds.join('|')}`
+}
+
+export function buildSrsearchForSeed(title: string): string {
+  return `morelike:${title}`
+}
+
+/** Wire preview: combined query when off, one line per seed when interleaving. */
+export function buildSrsearchPreview(seedText: string, interleave: boolean): string | null {
+  const seeds = parseSeedTitles(seedText)
+  if (!seeds.length) return null
+
+  if (!interleave) {
+    return buildSrsearch(seedText)
+  }
+
+  return seeds.map(buildSrsearchForSeed).join('\n')
+}
+
+/** Split total result limit across seeds (e.g. 20 / 3 → [7, 7, 6]). */
+export function perSeedLimits(totalLimit: number, seedCount: number): number[] {
+  if (seedCount <= 0) return []
+
+  const base = Math.floor(totalLimit / seedCount)
+  const extra = totalLimit % seedCount
+
+  return Array.from({ length: seedCount }, (_, i) => base + (i < extra ? 1 : 0))
+}
+
+/** Round-robin merge with dedupe; caps at totalLimit. */
+export function interleaveMorelikeHits(
+  lists: MorelikeSearchHit[][],
+  totalLimit: number,
+): MorelikeSearchHit[] {
+  if (!lists.length) return []
+
+  const seen = new Set<string>()
+  const result: MorelikeSearchHit[] = []
+  const maxLen = Math.max(...lists.map((list) => list.length))
+
+  for (let i = 0; i < maxLen && result.length < totalLimit; i++) {
+    for (const list of lists) {
+      if (result.length >= totalLimit) break
+
+      const hit = list[i]
+      if (!hit || seen.has(hit.title)) continue
+
+      seen.add(hit.title)
+      result.push(hit)
+    }
+  }
+
+  return result
+}
+
+function articleUrl(title: string): string {
+  return `https://${WIKI_HOST}/wiki/${encodeURIComponent(title.replace(/ /g, '_'))}`
+}
+
+function buildMorelikeSearchParams(
+  gsrsearch: string,
+  limit: number,
+  mltParams: Record<string, string>,
+  classicNoboostlinks: boolean,
+): URLSearchParams {
+  const params = new URLSearchParams({
+    action: 'query',
+    generator: 'search',
+    gsrsearch,
+    gsrnamespace: '0',
+    gsrlimit: String(limit),
+    prop: 'pageimages|description|revisions',
+    piprop: 'thumbnail',
+    pithumbsize: '160',
+    rvprop: 'timestamp|user|comment|content',
+    rvslots: 'main',
+    format: 'json',
+    formatversion: '2',
+    origin: '*',
+  })
+
+  if (classicNoboostlinks) {
+    params.set('gsrqiprofile', 'classic_noboostlinks')
+  }
+
+  for (const [key, value] of Object.entries(mltParams)) {
+    params.set(key, value)
+  }
+
+  return params
+}
+
+function buildMorelikeApiRequestUrlFromGsrsearch(
+  gsrsearch: string,
+  limit: number,
+  mltPreset: MorelikeMltPreset,
+  mltCustom: MorelikeMltCustomSettings,
+  classicNoboostlinks: boolean,
+): string {
+  const params = buildMorelikeSearchParams(
+    gsrsearch,
+    limit,
+    resolveMltParams(mltPreset, mltCustom),
+    classicNoboostlinks,
+  )
+  return `${API_URL}?${params.toString()}`
+}
+
+/** Exact URL(s) sent to the Action API (shared by fetch + UI). */
+export function buildMorelikeApiRequestUrls(
+  seedText: string,
+  totalLimit: number,
+  mltPreset: MorelikeMltPreset,
+  mltCustom: MorelikeMltCustomSettings,
+  classicNoboostlinks = true,
+  interleave = false,
+): string[] {
+  const seeds = parseSeedTitles(seedText)
+  if (!seeds.length) return []
+
+  if (!interleave) {
+    const gsrsearch = buildSrsearch(seedText)
+    if (!gsrsearch) return []
+
+    return [
+      buildMorelikeApiRequestUrlFromGsrsearch(
+        gsrsearch,
+        totalLimit,
+        mltPreset,
+        mltCustom,
+        classicNoboostlinks,
+      ),
+    ]
+  }
+
+  const limits = perSeedLimits(totalLimit, seeds.length)
+  const urls: string[] = []
+
+  for (let i = 0; i < seeds.length; i++) {
+    if (limits[i] <= 0) continue
+
+    urls.push(
+      buildMorelikeApiRequestUrlFromGsrsearch(
+        buildSrsearchForSeed(seeds[i]),
+        limits[i],
+        mltPreset,
+        mltCustom,
+        classicNoboostlinks,
+      ),
+    )
+  }
+
+  return urls
+}
+
+/** Exact URL sent to the Action API (shared by fetch + UI). */
+export function buildMorelikeApiRequestUrl(
+  seedText: string,
+  limit: number,
+  mltPreset: MorelikeMltPreset,
+  mltCustom: MorelikeMltCustomSettings,
+  classicNoboostlinks = true,
+  interleave = false,
+): string | null {
+  const urls = buildMorelikeApiRequestUrls(
+    seedText,
+    limit,
+    mltPreset,
+    mltCustom,
+    classicNoboostlinks,
+    interleave,
+  )
+
+  if (!urls.length) return null
+
+  return urls.join('\n')
+}
+
+async function fetchMorelikeHits(
+  requestUrl: string,
+  signal?: AbortSignal,
+): Promise<GeneratorPage[]> {
+  const response = await fetch(requestUrl, {
+    signal,
+    headers: wikimediaApiFetchHeaders('morelike-search'),
+  })
+
+  if (!response.ok) {
+    throw new MorelikeFetchError(`Search failed (HTTP ${response.status})`, 'http')
+  }
+
+  const data = (await response.json()) as GeneratorSearchResponse
+
+  if (data.error) {
+    throw new MorelikeFetchError(data.error.info ?? data.error.code ?? 'Search failed', 'http')
+  }
+
+  const pages = data.query?.pages ?? []
+
+  return [...pages].sort((a, b) => (a.index ?? 0) - (b.index ?? 0))
+}
+
+function mapRevisionFields(revision: GeneratorRevision | undefined): {
+  timestamp: string
+  author?: string
+  comment?: string
+  content?: string
+} {
+  return {
+    timestamp: revision?.timestamp ?? '',
+    author: revision?.user,
+    comment: revision?.comment,
+    content: revision?.slots?.main?.content,
+  }
+}
+
+function mapPageToHit(page: GeneratorPage): MorelikeSearchHit {
+  const latest = mapRevisionFields(page.revisions?.[0])
+
+  return {
+    title: page.title,
+    description: page.description?.trim() ?? '',
+    timestamp: latest.timestamp,
+    pageUrl: articleUrl(page.title),
+    revisionAuthor: latest.author,
+    revisionComment: latest.comment,
+    revisionContent: latest.content,
+    thumbnail: page.thumbnail
+      ? {
+          url: page.thumbnail.source,
+          width: page.thumbnail.width,
+          height: page.thumbnail.height,
+        }
+      : undefined,
+  }
+}
+
+function sortByNewestEditFirst(hits: MorelikeSearchHit[]): MorelikeSearchHit[] {
+  return [...hits].sort((a, b) => {
+    const aTime = a.timestamp ? Date.parse(a.timestamp) : Number.NaN
+    const bTime = b.timestamp ? Date.parse(b.timestamp) : Number.NaN
+
+    if (Number.isNaN(aTime) && Number.isNaN(bTime)) return 0
+    if (Number.isNaN(aTime)) return 1
+    if (Number.isNaN(bTime)) return -1
+
+    return bTime - aTime
+  })
+}
+
+/** Client-side sort — API results always stay in relevance order. */
+export function sortMorelikeHits(
+  hits: MorelikeSearchHit[],
+  sortOrder: MorelikeSortOrder,
+): MorelikeSearchHit[] {
+  if (sortOrder === 'lastEdit') {
+    return sortByNewestEditFirst(hits)
+  }
+
+  return hits
+}
+
+async function fetchMorelikeResultsCombined(
+  seedText: string,
+  options: {
+    limit: number
+    mltPreset: MorelikeMltPreset
+    mltCustom: MorelikeMltCustomSettings
+    classicNoboostlinks: boolean
+    signal?: AbortSignal
+  },
+): Promise<MorelikeSearchHit[]> {
+  const requestUrl = buildMorelikeApiRequestUrl(
+    seedText,
+    options.limit,
+    options.mltPreset,
+    options.mltCustom,
+    options.classicNoboostlinks,
+    false,
+  )
+
+  if (!requestUrl) {
+    throw new MorelikeFetchError('Add at least one seed page title', 'empty')
+  }
+
+  const seedTitles = new Set(parseSeedTitles(seedText))
+  const pages = await fetchMorelikeHits(requestUrl, options.signal)
+
+  return pages
+    .filter((page) => !seedTitles.has(page.title))
+    .map(mapPageToHit)
+}
+
+async function fetchMorelikeResultsInterleaved(
+  seedText: string,
+  options: {
+    limit: number
+    mltPreset: MorelikeMltPreset
+    mltCustom: MorelikeMltCustomSettings
+    classicNoboostlinks: boolean
+    signal?: AbortSignal
+  },
+): Promise<MorelikeSearchHit[]> {
+  const seeds = parseSeedTitles(seedText)
+  if (!seeds.length) {
+    throw new MorelikeFetchError('Add at least one seed page title', 'empty')
+  }
+
+  const seedTitles = new Set(seeds)
+  const limits = perSeedLimits(options.limit, seeds.length)
+  const lists: MorelikeSearchHit[][] = []
+
+  for (let i = 0; i < seeds.length; i++) {
+    if (options.signal?.aborted) {
+      throw new MorelikeFetchError('Request aborted', 'aborted')
+    }
+
+    const limit = limits[i]
+    if (limit <= 0) continue
+
+    const requestUrl = buildMorelikeApiRequestUrlFromGsrsearch(
+      buildSrsearchForSeed(seeds[i]),
+      limit,
+      options.mltPreset,
+      options.mltCustom,
+      options.classicNoboostlinks,
+    )
+
+    const pages = await fetchMorelikeHits(requestUrl, options.signal)
+
+    lists.push(
+      pages
+        .filter((page) => !seedTitles.has(page.title))
+        .map(mapPageToHit),
+    )
+  }
+
+  return interleaveMorelikeHits(lists, options.limit)
+}
+
+export async function fetchMorelikeResults(
+  seedText: string,
+  options: {
+    limit: number
+    mltPreset: MorelikeMltPreset
+    mltCustom: MorelikeMltCustomSettings
+    classicNoboostlinks?: boolean
+    interleave?: boolean
+    signal?: AbortSignal
+  },
+): Promise<MorelikeSearchHit[]> {
+  if (options.signal?.aborted) {
+    throw new MorelikeFetchError('Request aborted', 'aborted')
+  }
+
+  const fetchOptions = {
+    limit: options.limit,
+    mltPreset: options.mltPreset,
+    mltCustom: options.mltCustom,
+    classicNoboostlinks: options.classicNoboostlinks ?? true,
+    signal: options.signal,
+  }
+
+  if (options.interleave) {
+    return fetchMorelikeResultsInterleaved(seedText, fetchOptions)
+  }
+
+  return fetchMorelikeResultsCombined(seedText, fetchOptions)
+}
diff --git a/src/prototypes/morelike-playground/formatEditComment.ts b/src/prototypes/morelike-playground/formatEditComment.ts
new file mode 100644
index 0000000..5b5827f
--- /dev/null
+++ b/src/prototypes/morelike-playground/formatEditComment.ts
@@ -0,0 +1,129 @@
+export type EditCommentPart =
+  | { type: 'text'; value: string }
+  | { type: 'section'; value: string }
+  | { type: 'link'; value: string }
+
+function collapseWhitespace(text: string): string {
+  return text.replace(/\s+/g, ' ').trim()
+}
+
+function stripWikiMarkup(text: string): string {
+  let stripped = text
+
+  stripped = stripped.replace(/<[^>]+>/g, '')
+  stripped = stripped.replace(/\{\|[\s\S]*?\|\}/g, '')
+
+  let previous = ''
+  while (previous !== stripped) {
+    previous = stripped
+    stripped = stripped.replace(/\{\{[^{}]*(?:\{[^{}]*\}[^{}]*)*\}\}/g, '')
+  }
+
+  stripped = stripped.replace(/'''''(.+?)'''''/g, '$1')
+  stripped = stripped.replace(/'''(.+?)'''/g, '$1')
+  stripped = stripped.replace(/''(.+?)''/g, '$1')
+  stripped = stripped.replace(/''/g, '')
+  stripped = stripped.replace(/^=+\s*(.*?)\s*=+$/gm, '$1')
+  stripped = stripped.replace(/^[*#:;]+/gm, '')
+
+  return stripped
+}
+
+function removeNonLinkWiki(text: string): string {
+  let cleaned = text
+
+  cleaned = cleaned.replace(/\[\[(?:File|Image|Media|Category):[^\]]*]]/gi, '')
+  cleaned = cleaned.replace(/\[(?:https?:\/\/[^\s\]]+)(?:\s+([^\]]+))?\]/gi, '$1')
+
+  return cleaned
+}
+
+function appendTextPart(parts: EditCommentPart[], value: string): void {
+  const text = collapseWhitespace(stripWikiMarkup(value))
+  if (!text.length) return
+
+  const last = parts[parts.length - 1]
+  if (last?.type === 'text') {
+    last.value = collapseWhitespace(`${last.value}${text}`)
+    return
+  }
+
+  parts.push({ type: 'text', value: text })
+}
+
+function wikiSummaryToParts(wiki: string): EditCommentPart[] {
+  const parts: EditCommentPart[] = []
+  const text = removeNonLinkWiki(wiki)
+  const linkPattern = /\[\[([^|\]]+)\|([^\]]+)]]|\[\[([^\]]+)]]/g
+
+  let lastIndex = 0
+  let match: RegExpExecArray | null
+
+  while ((match = linkPattern.exec(text)) !== null) {
+    appendTextPart(parts, text.slice(lastIndex, match.index))
+
+    const display = collapseWhitespace(stripWikiMarkup((match[2] ?? match[3]).trim()))
+    if (display.length) {
+      parts.push({ type: 'link', value: display })
+    }
+
+    lastIndex = match.index + match[0].length
+  }
+
+  appendTextPart(parts, text.slice(lastIndex))
+  return parts
+}
+
+function hasSummaryContent(parts: EditCommentPart[]): boolean {
+  return parts.some((part) => part.value.trim().length > 0)
+}
+
+function quoteSummaryParts(parts: EditCommentPart[]): EditCommentPart[] {
+  if (!hasSummaryContent(parts)) return []
+
+  if (parts[0]?.type === 'text') {
+    parts[0].value = parts[0].value.trimStart()
+  }
+
+  return [{ type: 'text', value: '"' }, ...parts, { type: 'text', value: '"' }]
+}
+
+/** Structured edit comment for card display (arrow, section label, quoted summary). */
+export function parseEditComment(raw: string): EditCommentPart[] {
+  const trimmed = raw.trim()
+  if (!trimmed.length) return []
+
+  const sectionMatch = trimmed.match(/^\/\*\s*(.*?)\s*\*\/\s*(.*)$/s)
+  if (sectionMatch) {
+    const section = collapseWhitespace(sectionMatch[1])
+    const restParts = quoteSummaryParts(wikiSummaryToParts(sectionMatch[2]))
+
+    if (!section.length && !restParts.length) {
+      return []
+    }
+
+    if (!section.length) {
+      return restParts
+    }
+
+    const parts: EditCommentPart[] = [
+      { type: 'text', value: '→' },
+      { type: 'section', value: section },
+    ]
+
+    if (restParts.length) {
+      parts.push({ type: 'text', value: ':' }, { type: 'text', value: ' ' }, ...restParts)
+    }
+
+    return parts
+  }
+
+  return quoteSummaryParts(wikiSummaryToParts(trimmed))
+}
+
+/** Plain-text join (e.g. empty checks). */
+export function formatEditComment(raw: string): string {
+  return parseEditComment(raw)
+    .map((part) => part.value)
+    .join('')
+}
diff --git a/src/prototypes/morelike-playground/index.vue b/src/prototypes/morelike-playground/index.vue
new file mode 100644
index 0000000..987a556
--- /dev/null
+++ b/src/prototypes/morelike-playground/index.vue
@@ -0,0 +1,564 @@
+<script setup lang="ts">
+import { computed, onMounted, ref, watch } from 'vue'
+import {
+  CdxButton,
+  CdxCard,
+  CdxField,
+  CdxMessage,
+  CdxSelect,
+  CdxTextArea,
+  CdxToggleSwitch,
+} from '@wikimedia/codex'
+
+import ChromeWrapper from '@/components/chrome/ChromeWrapper.vue'
+import SpecialPageWrapper from '@/components/SpecialPageWrapper.vue'
+
+import {
+  buildMorelikeApiRequestUrl,
+  buildSrsearchPreview,
+  fetchMorelikeResults,
+  MorelikeFetchError,
+  parseSeedTitles,
+  sortMorelikeHits,
+  type MorelikeSearchHit,
+} from './fetchMorelike'
+import {
+  CIRRUS_MLT_EXTENSION_DEFAULTS,
+  DEFAULT_MLT_CUSTOM,
+  MLT_PRESET_LABELS,
+  SORT_ORDER_LABELS,
+  type MorelikeMltCustomSettings,
+  type MorelikeMltPreset,
+  type MorelikeSortOrder,
+} from './morelikeMlt'
+import {
+  DEFAULT_MORELIKE_PLAYGROUND_STATE,
+  loadMorelikePlaygroundState,
+  persistMorelikePlaygroundState,
+} from './morelikeStorage'
+import EditAttributionLine from './EditAttributionLine.vue'
+import { formatEditComment, parseEditComment } from './formatEditComment'
+
+definePage({
+  meta: {
+    title: 'Morelike playground',
+    description: 'Try CirrusSearch morelike with many seed pages.',
+  },
+})
+
+const seedText = ref('')
+const resultLimit = ref(20)
+const sortOrder = ref<MorelikeSortOrder>('relevance')
+const mltPreset = ref<MorelikeMltPreset>('default')
+const mltCustom = ref<MorelikeMltCustomSettings>({
+  ...DEFAULT_MORELIKE_PLAYGROUND_STATE.mltCustom,
+})
+const classicNoboostlinks = ref(DEFAULT_MORELIKE_PLAYGROUND_STATE.classicNoboostlinks)
+const interleave = ref(DEFAULT_MORELIKE_PLAYGROUND_STATE.interleave)
+
+const results = ref<MorelikeSearchHit[]>([])
+const sortedResults = computed(() => sortMorelikeHits(results.value, sortOrder.value))
+const isSearching = ref(false)
+const errorMessage = ref('')
+const hasSearched = ref(false)
+
+let abortController: AbortController | null = null
+let persistDebounce: ReturnType<typeof setTimeout> | null = null
+
+const seedTitles = computed(() => parseSeedTitles(seedText.value))
+
+const canSearch = computed(() => seedTitles.value.length > 0 && !isSearching.value)
+
+const sortOrderMenuItems = computed(() =>
+  (Object.keys(SORT_ORDER_LABELS) as MorelikeSortOrder[]).map((value) => ({
+    value,
+    label: SORT_ORDER_LABELS[value],
+  })),
+)
+
+const mltPresetMenuItems = computed(() =>
+  (Object.keys(MLT_PRESET_LABELS) as MorelikeMltPreset[]).map((value) => ({
+    value,
+    label: MLT_PRESET_LABELS[value],
+  })),
+)
+
+const mltFieldsMenuItems = [
+  { value: 'text', label: 'text (default)' },
+  { value: 'title', label: 'title' },
+  { value: 'opening_text', label: 'opening_text' },
+]
+
+const gsrsearch = computed(() => buildSrsearchPreview(seedText.value, interleave.value) ?? '')
+
+const showMultipleRequestUrls = computed(
+  () => interleave.value && seedTitles.value.length > 1,
+)
+
+const requestUrl = computed(
+  () =>
+    buildMorelikeApiRequestUrl(
+      seedText.value,
+      resultLimit.value,
+      mltPreset.value,
+      mltCustom.value,
+      classicNoboostlinks.value,
+      interleave.value,
+    ) ?? '',
+)
+
+const showCustomMlt = computed(() => mltPreset.value === 'custom')
+
+function formatRevisionCommentLine(hit: MorelikeSearchHit): string {
+  if (!hit.revisionComment?.trim()) return ''
+  return formatEditComment(hit.revisionComment)
+}
+
+function schedulePersist(immediate = false): void {
+  if (persistDebounce) {
+    clearTimeout(persistDebounce)
+    persistDebounce = null
+  }
+
+  const persist = () => {
+    persistMorelikePlaygroundState({
+      seedText: seedText.value,
+      resultLimit: resultLimit.value,
+      sortOrder: sortOrder.value,
+      mltPreset: mltPreset.value,
+      mltCustom: mltCustom.value,
+      classicNoboostlinks: classicNoboostlinks.value,
+      interleave: interleave.value,
+    })
+  }
+
+  if (immediate) {
+    persist()
+    return
+  }
+
+  persistDebounce = setTimeout(persist, 300)
+}
+
+async function onSearch(): Promise<void> {
+  if (!canSearch.value) return
+
+  abortController?.abort()
+  abortController = new AbortController()
+
+  isSearching.value = true
+  errorMessage.value = ''
+  hasSearched.value = true
+
+  try {
+    results.value = await fetchMorelikeResults(seedText.value, {
+      limit: resultLimit.value,
+      mltPreset: mltPreset.value,
+      mltCustom: mltCustom.value,
+      classicNoboostlinks: classicNoboostlinks.value,
+      interleave: interleave.value,
+      signal: abortController.signal,
+    })
+
+    console.log(
+      '[morelike] revision fields',
+      results.value.map((hit) => ({
+        title: hit.title,
+        author: hit.revisionAuthor,
+        comment: hit.revisionComment,
+        content: hit.revisionContent,
+        timestamp: hit.timestamp,
+      })),
+    )
+  } catch (error) {
+    if (error instanceof MorelikeFetchError && error.code === 'aborted') {
+      return
+    }
+
+    results.value = []
+    errorMessage.value =
+      error instanceof MorelikeFetchError
+        ? error.message
+        : error instanceof Error
+          ? error.message
+          : 'Search failed'
+  } finally {
+    isSearching.value = false
+  }
+}
+
+onMounted(() => {
+  const stored = loadMorelikePlaygroundState()
+  seedText.value = stored.seedText
+  resultLimit.value = stored.resultLimit
+  sortOrder.value = stored.sortOrder
+  mltPreset.value = stored.mltPreset
+  mltCustom.value = { ...stored.mltCustom }
+  classicNoboostlinks.value = stored.classicNoboostlinks
+  interleave.value = stored.interleave
+})
+
+watch(seedText, () => schedulePersist(false))
+watch(
+  [resultLimit, sortOrder, mltPreset, mltCustom, classicNoboostlinks, interleave],
+  () => schedulePersist(true),
+  { deep: true },
+)
+</script>
+
+<template>
+  <ChromeWrapper :last-edited-notice="false">
+    <SpecialPageWrapper title="Morelike playground">
+      <section class="morelike-playground__controls">
+        <CdxField>
+          <template #label>Seed pages</template>
+          <template #description>One Wikipedia article title per line (commas also work)</template>
+          <CdxTextArea
+            v-model="seedText"
+            :rows="8"
+            placeholder="Gorillaz&#10;Wet Leg"
+          />
+        </CdxField>
+
+        <CdxField>
+          <template #label>Result limit: {{ resultLimit }}</template>
+          <template #description>Number of morelike results to return (1–100)</template>
+          <input
+            v-model.number="resultLimit"
+            class="morelike-playground__range"
+            type="range"
+            min="1"
+            max="100"
+            step="1"
+          />
+        </CdxField>
+
+        <CdxField>
+          <template #label>Multiple requests</template>
+          <template #description>
+            One morelike query per seed, then round-robin merge (~N total, same as the limit
+            slider). Off uses a single combined `morelike:A|B|…` query.
+          </template>
+          <CdxToggleSwitch v-model="interleave" />
+        </CdxField>
+
+        <CdxField>
+          <template #label>MLT tuning</template>
+          <template #description>
+            “No overrides” sends no cirrusMlt* params (wiki default). Custom only sends params
+            that differ from extension defaults.
+          </template>
+          <CdxSelect
+            v-model:selected="mltPreset"
+            :menu-items="mltPresetMenuItems"
+            default-label="No overrides (wiki default)"
+          />
+        </CdxField>
+
+        <div v-if="showCustomMlt" class="morelike-playground__custom-mlt">
+          <CdxField>
+            <template #label>Max query terms: {{ mltCustom.maxQueryTerms }}</template>
+            <template #description>
+              Terms extracted from seed articles to build the query (max 100). Extension
+              default: {{ CIRRUS_MLT_EXTENSION_DEFAULTS.maxQueryTerms }} (omitted when unchanged).
+            </template>
+            <input
+              v-model.number="mltCustom.maxQueryTerms"
+              class="morelike-playground__range"
+              type="range"
+              min="1"
+              max="100"
+              step="1"
+            />
+          </CdxField>
+
+          <CdxField>
+            <template #label>Min term frequency: {{ mltCustom.minTermFreq }}</template>
+            <template #description>
+              How often a term must appear in seed text to be used. Extension default:
+              {{ CIRRUS_MLT_EXTENSION_DEFAULTS.minTermFreq }}.
+            </template>
+            <input
+              v-model.number="mltCustom.minTermFreq"
+              class="morelike-playground__range"
+              type="range"
+              min="1"
+              max="10"
+              step="1"
+            />
+          </CdxField>
+
+          <CdxField>
+            <template #label>Min doc frequency: {{ mltCustom.minDocFreq }}</template>
+            <template #description>
+              Minimum shard document frequency for a term. Extension default:
+              {{ CIRRUS_MLT_EXTENSION_DEFAULTS.minDocFreq }}.
+            </template>
+            <input
+              v-model.number="mltCustom.minDocFreq"
+              class="morelike-playground__range"
+              type="range"
+              min="1"
+              max="10"
+              step="1"
+            />
+          </CdxField>
+
+          <CdxField>
+            <template #label>Terms to match: {{ mltCustom.minimumShouldMatchPercent }}%</template>
+            <template #description>
+              Percentage of query terms a result must match. Extension default:
+              {{ CIRRUS_MLT_EXTENSION_DEFAULTS.minimumShouldMatchPercent }}%.
+            </template>
+            <input
+              v-model.number="mltCustom.minimumShouldMatchPercent"
+              class="morelike-playground__range"
+              type="range"
+              min="1"
+              max="100"
+              step="1"
+            />
+          </CdxField>
+
+          <CdxField>
+            <template #label>Min word length: {{ mltCustom.minWordLength }}</template>
+            <template #description>
+              Minimum character length for a term. Extension default:
+              {{ CIRRUS_MLT_EXTENSION_DEFAULTS.minWordLength }}.
+            </template>
+            <input
+              v-model.number="mltCustom.minWordLength"
+              class="morelike-playground__range"
+              type="range"
+              min="0"
+              max="10"
+              step="1"
+            />
+          </CdxField>
+
+          <CdxField>
+            <template #label>MLT fields</template>
+            <template #description>
+              Field(s) to extract terms from. Extension default: {{ CIRRUS_MLT_EXTENSION_DEFAULTS.fields }}
+              (omitted when unchanged).
+            </template>
+            <CdxSelect
+              v-model:selected="mltCustom.fields"
+              :menu-items="mltFieldsMenuItems"
+              default-label="text"
+            />
+          </CdxField>
+
+          <CdxField>
+            <template #label>Use fields only</template>
+            <template #description>
+              When on, only the selected field is used (not full article text extraction).
+              Extension default: {{ CIRRUS_MLT_EXTENSION_DEFAULTS.useFieldsOnly ? 'on' : 'off' }}.
+            </template>
+            <CdxToggleSwitch v-model="mltCustom.useFieldsOnly">
+              cirrusMltUseFields
+            </CdxToggleSwitch>
+          </CdxField>
+        </div>
+
+        <CdxField>
+          <template #label>Disable link boosting</template>
+          <template #description>
+            When on, adds `gsrqiprofile=classic_noboostlinks` — ranks by text similarity without
+            incoming-link rescore. When off, wiki default applies.
+          </template>
+          <CdxToggleSwitch v-model="classicNoboostlinks" />
+        </CdxField>
+
+        <CdxField>
+          <template #label>Search query</template>
+          <template #description>
+            How seed pages are encoded for morelike — one combined query, or one per seed when
+            multiple requests is on.
+          </template>
+          <CdxTextArea
+            class="morelike-playground__wire-value"
+            :model-value="gsrsearch"
+            disabled
+            :rows="interleave && seedTitles.length > 1 ? Math.min(seedTitles.length, 6) : 1"
+          />
+        </CdxField>
+
+        <CdxField>
+          <template #label>{{ showMultipleRequestUrls ? 'Request URLs' : 'Request URL' }}</template>
+          <template #description>
+            Exact GET on Search. Sort order is applied after the response, not in this URL.
+          </template>
+          <CdxTextArea
+            class="morelike-playground__wire-value"
+            :model-value="requestUrl"
+            disabled
+            :rows="showMultipleRequestUrls ? Math.min(seedTitles.length * 2, 12) : 4"
+          />
+        </CdxField>
+
+        <div class="morelike-playground__actions">
+          <CdxButton action="progressive" :disabled="!canSearch" @click="onSearch">
+            {{ isSearching ? 'Searching…' : 'Search' }}
+          </CdxButton>
+          <p v-if="isSearching" class="morelike-playground__status">Fetching results…</p>
+        </div>
+
+        <CdxField>
+          <template #label>Sort results by</template>
+          <CdxSelect
+            v-model:selected="sortOrder"
+            :menu-items="sortOrderMenuItems"
+            default-label="Most relevant"
+          />
+        </CdxField>
+      </section>
+
+      <section class="morelike-playground__results">
+        <CdxMessage v-if="errorMessage" type="error" :allow-user-dismiss="false">
+          {{ errorMessage }}
+        </CdxMessage>
+
+        <CdxMessage
+          v-else-if="hasSearched && !isSearching && results.length === 0"
+          type="warning"
+          :allow-user-dismiss="false"
+        >
+          No results — try different seed pages or MLT tuning.
+        </CdxMessage>
+
+        <ul v-if="results.length" class="morelike-playground__list">
+          <li v-for="hit in sortedResults" :key="hit.title" class="morelike-playground__list-item">
+            <CdxCard
+              :url="hit.pageUrl"
+              :thumbnail="hit.thumbnail"
+              force-thumbnail
+              class="morelike-playground__card"
+            >
+              <template #title>{{ hit.title }}</template>
+              <template
+                v-if="hit.description || hit.timestamp || hit.revisionAuthor || formatRevisionCommentLine(hit)"
+                #description
+              >
+                <span v-if="hit.description" class="morelike-playground__description">
+                  {{ hit.description }}
+                </span>
+                <span
+                  v-if="hit.timestamp || hit.revisionAuthor || formatRevisionCommentLine(hit)"
+                  class="morelike-playground__edit-block"
+                >
+                  <span v-if="formatRevisionCommentLine(hit)" class="morelike-playground__edit-meta">
+                    <template
+                      v-for="(part, partIndex) in parseEditComment(hit.revisionComment ?? '')"
+                      :key="partIndex"
+                    >{{ part.value }}</template>
+                  </span>
+                  <EditAttributionLine :timestamp="hit.timestamp" :author="hit.revisionAuthor" />
+                </span>
+              </template>
+            </CdxCard>
+          </li>
+        </ul>
+      </section>
+    </SpecialPageWrapper>
+  </ChromeWrapper>
+</template>
+
+<style scoped>
+.morelike-playground__controls {
+  display: flex;
+  flex-direction: column;
+  gap: var(--spacing-100);
+  margin-bottom: var(--spacing-200);
+}
+
+.morelike-playground__custom-mlt {
+  display: flex;
+  flex-direction: column;
+  gap: var(--spacing-100);
+  padding: var(--spacing-100);
+  border: var(--border-width-base) solid var(--border-color-subtle);
+  border-radius: var(--border-radius-base);
+}
+
+.morelike-playground__range {
+  width: 100%;
+  margin: 0;
+  accent-color: var(--color-progressive);
+}
+
+.morelike-playground__wire-value :deep(textarea) {
+  font-family: var(--font-family-monospace, monospace);
+  font-size: var(--font-size-small);
+  line-height: var(--line-height-small);
+  overflow-wrap: anywhere;
+  word-break: break-all;
+}
+
+.morelike-playground__actions {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: var(--spacing-100);
+}
+
+.morelike-playground__status {
+  margin: 0;
+  font-size: var(--font-size-medium);
+  color: var(--color-subtle);
+}
+
+.morelike-playground__results {
+  display: flex;
+  flex-direction: column;
+  gap: var(--spacing-100);
+}
+
+.morelike-playground__list {
+  display: flex;
+  flex-direction: column;
+  gap: var(--spacing-50);
+  max-width: 45rem;
+  margin: 0;
+  padding: 0;
+  list-style: none;
+}
+
+.morelike-playground__list-item {
+  min-width: 0;
+}
+
+.morelike-playground__card {
+  width: 100%;
+}
+
+@media (hover: hover) and (pointer: fine) {
+  .morelike-playground__card.cdx-card--is-link:hover {
+    background-color: var(--background-color-interactive-subtle, #f8f9fa);
+  }
+}
+
+.morelike-playground__card :deep(.morelike-playground__editor) {
+  font-weight: var(--font-weight-bold);
+  color: var(--color-base);
+}
+
+.morelike-playground__description {
+  display: block;
+  margin: 0;
+}
+
+.morelike-playground__edit-block {
+  display: block;
+  margin-top: var(--spacing-50);
+}
+
+.morelike-playground__card :deep(.morelike-playground__edit-meta) {
+  display: block;
+  margin: 0;
+  font-size: var(--font-size-small);
+  color: var(--color-subtle);
+  line-height: var(--line-height-small);
+}
+
+</style>
diff --git a/src/prototypes/morelike-playground/morelikeMlt.ts b/src/prototypes/morelike-playground/morelikeMlt.ts
new file mode 100644
index 0000000..7312a79
--- /dev/null
+++ b/src/prototypes/morelike-playground/morelikeMlt.ts
@@ -0,0 +1,151 @@
+export type MorelikeMltPreset = 'default' | 'custom'
+
+export type MorelikeSortOrder = 'relevance' | 'lastEdit'
+
+/** CirrusSearch more_like_this URL params (see Help:CirrusSearch#Morelike). */
+export interface MorelikeMltCustomSettings {
+  maxQueryTerms: number
+  minTermFreq: number
+  minDocFreq: number
+  maxDocFreq: number | null
+  minWordLength: number
+  maxWordLength: number | null
+  minimumShouldMatchPercent: number
+  fields: 'text' | 'title' | 'opening_text'
+  useFieldsOnly: boolean
+}
+
+/**
+ * Extension defaults from CirrusSearch $wgCirrusSearchMoreLikeThisConfig
+ * (docs/settings.txt). The “Default” preset omits all cirrusMlt* params so the
+ * wiki uses these server-side — Custom only sends params that differ from this.
+ */
+export const CIRRUS_MLT_EXTENSION_DEFAULTS: MorelikeMltCustomSettings = {
+  maxQueryTerms: 25,
+  minTermFreq: 2,
+  minDocFreq: 2,
+  maxDocFreq: null,
+  minWordLength: 0,
+  maxWordLength: null,
+  minimumShouldMatchPercent: 30,
+  fields: 'text',
+  useFieldsOnly: false,
+}
+
+/** Starting values for the Custom sliders (matches extension defaults). */
+export const DEFAULT_MLT_CUSTOM: MorelikeMltCustomSettings = {
+  ...CIRRUS_MLT_EXTENSION_DEFAULTS,
+}
+
+export const MLT_PRESET_LABELS: Record<MorelikeMltPreset, string> = {
+  default: 'No overrides (wiki default)',
+  custom: 'Custom',
+}
+
+export const SORT_ORDER_LABELS: Record<MorelikeSortOrder, string> = {
+  relevance: 'Most relevant',
+  lastEdit: 'Most recent edit',
+}
+
+function clampInt(value: number, min: number, max: number): number {
+  return Math.min(max, Math.max(min, Math.round(value)))
+}
+
+export function normalizeMltCustom(input: unknown): MorelikeMltCustomSettings {
+  if (typeof input !== 'object' || input === null) {
+    return { ...DEFAULT_MLT_CUSTOM }
+  }
+
+  const record = input as Record<string, unknown>
+  const fields =
+    record.fields === 'title' || record.fields === 'opening_text' || record.fields === 'text'
+      ? record.fields
+      : DEFAULT_MLT_CUSTOM.fields
+
+  return {
+    maxQueryTerms:
+      typeof record.maxQueryTerms === 'number'
+        ? clampInt(record.maxQueryTerms, 1, 100)
+        : DEFAULT_MLT_CUSTOM.maxQueryTerms,
+    minTermFreq:
+      typeof record.minTermFreq === 'number'
+        ? clampInt(record.minTermFreq, 1, 20)
+        : DEFAULT_MLT_CUSTOM.minTermFreq,
+    minDocFreq:
+      typeof record.minDocFreq === 'number'
+        ? clampInt(record.minDocFreq, 1, 20)
+        : DEFAULT_MLT_CUSTOM.minDocFreq,
+    maxDocFreq:
+      typeof record.maxDocFreq === 'number'
+        ? clampInt(record.maxDocFreq, 1, 1_000_000)
+        : null,
+    minWordLength:
+      typeof record.minWordLength === 'number'
+        ? clampInt(record.minWordLength, 0, 20)
+        : DEFAULT_MLT_CUSTOM.minWordLength,
+    maxWordLength:
+      typeof record.maxWordLength === 'number' ? clampInt(record.maxWordLength, 1, 100) : null,
+    minimumShouldMatchPercent:
+      typeof record.minimumShouldMatchPercent === 'number'
+        ? clampInt(record.minimumShouldMatchPercent, 1, 100)
+        : DEFAULT_MLT_CUSTOM.minimumShouldMatchPercent,
+    fields,
+    useFieldsOnly:
+      typeof record.useFieldsOnly === 'boolean'
+        ? record.useFieldsOnly
+        : DEFAULT_MLT_CUSTOM.useFieldsOnly,
+  }
+}
+
+function buildCustomMltParams(custom: MorelikeMltCustomSettings): Record<string, string> {
+  const normalized = normalizeMltCustom(custom)
+  const defaults = CIRRUS_MLT_EXTENSION_DEFAULTS
+  const params: Record<string, string> = {}
+
+  if (normalized.maxQueryTerms !== defaults.maxQueryTerms) {
+    params.cirrusMltMaxQueryTerms = String(normalized.maxQueryTerms)
+  }
+
+  if (normalized.minTermFreq !== defaults.minTermFreq) {
+    params.cirrusMltMinTermFreq = String(normalized.minTermFreq)
+  }
+
+  if (normalized.minDocFreq !== defaults.minDocFreq) {
+    params.cirrusMltMinDocFreq = String(normalized.minDocFreq)
+  }
+
+  if (normalized.minWordLength !== defaults.minWordLength) {
+    params.cirrusMltMinWordLength = String(normalized.minWordLength)
+  }
+
+  if (normalized.minimumShouldMatchPercent !== defaults.minimumShouldMatchPercent) {
+    params.cirrusMltMinimumShouldMatch = `${normalized.minimumShouldMatchPercent}%`
+  }
+
+  if (normalized.maxDocFreq !== null) {
+    params.cirrusMltMaxDocFreq = String(normalized.maxDocFreq)
+  }
+
+  if (normalized.maxWordLength !== null) {
+    params.cirrusMltMaxWordLength = String(normalized.maxWordLength)
+  }
+
+  if (normalized.useFieldsOnly) {
+    params.cirrusMltUseFields = 'true'
+  }
+
+  if (normalized.useFieldsOnly || normalized.fields !== defaults.fields) {
+    params.cirrusMltFields = normalized.fields
+  }
+
+  return params
+}
+
+export function resolveMltParams(
+  preset: MorelikeMltPreset,
+  custom: MorelikeMltCustomSettings,
+): Record<string, string> {
+  if (preset === 'default') return {}
+
+  return buildCustomMltParams(custom)
+}
diff --git a/src/prototypes/morelike-playground/morelikeStorage.ts b/src/prototypes/morelike-playground/morelikeStorage.ts
new file mode 100644
index 0000000..61378af
--- /dev/null
+++ b/src/prototypes/morelike-playground/morelikeStorage.ts
@@ -0,0 +1,118 @@
+import {
+  DEFAULT_MLT_CUSTOM,
+  normalizeMltCustom,
+  type MorelikeMltCustomSettings,
+  type MorelikeMltPreset,
+  type MorelikeSortOrder,
+} from './morelikeMlt'
+
+export interface MorelikePlaygroundState {
+  seedText: string
+  resultLimit: number
+  sortOrder: MorelikeSortOrder
+  mltPreset: MorelikeMltPreset
+  mltCustom: MorelikeMltCustomSettings
+  classicNoboostlinks: boolean
+  interleave: boolean
+}
+
+const STORAGE_KEY = 'protowiki-morelike-playground-v1'
+
+export const DEFAULT_MORELIKE_PLAYGROUND_STATE: MorelikePlaygroundState = {
+  seedText: '',
+  resultLimit: 20,
+  sortOrder: 'relevance',
+  mltPreset: 'default',
+  mltCustom: { ...DEFAULT_MLT_CUSTOM },
+  classicNoboostlinks: true,
+  interleave: false,
+}
+
+function clampResultLimit(value: number): number {
+  return Math.min(100, Math.max(1, Math.round(value)))
+}
+
+function isSortOrder(value: unknown): value is MorelikeSortOrder {
+  return value === 'relevance' || value === 'lastEdit'
+}
+
+function isMltPreset(value: unknown): value is MorelikeMltPreset {
+  return value === 'default' || value === 'custom'
+}
+
+function normalizeMltPreset(value: unknown): MorelikeMltPreset {
+  if (isMltPreset(value)) return value
+  // Removed presets fall back to wiki default.
+  if (value === 'balancedTitles' || value === 'fewerTerms') return 'default'
+  return DEFAULT_MORELIKE_PLAYGROUND_STATE.mltPreset
+}
+
+function normalizeState(input: unknown): MorelikePlaygroundState {
+  if (typeof input !== 'object' || input === null) {
+    return { ...DEFAULT_MORELIKE_PLAYGROUND_STATE, mltCustom: { ...DEFAULT_MLT_CUSTOM } }
+  }
+
+  const record = input as Record<string, unknown>
+
+  return {
+    seedText: typeof record.seedText === 'string' ? record.seedText : DEFAULT_MORELIKE_PLAYGROUND_STATE.seedText,
+    resultLimit:
+      typeof record.resultLimit === 'number'
+        ? clampResultLimit(record.resultLimit)
+        : DEFAULT_MORELIKE_PLAYGROUND_STATE.resultLimit,
+    sortOrder: isSortOrder(record.sortOrder)
+      ? record.sortOrder
+      : DEFAULT_MORELIKE_PLAYGROUND_STATE.sortOrder,
+    mltPreset: normalizeMltPreset(record.mltPreset),
+    mltCustom: normalizeMltCustom(record.mltCustom),
+    classicNoboostlinks:
+      typeof record.classicNoboostlinks === 'boolean'
+        ? record.classicNoboostlinks
+        : DEFAULT_MORELIKE_PLAYGROUND_STATE.classicNoboostlinks,
+    interleave:
+      typeof record.interleave === 'boolean'
+        ? record.interleave
+        : DEFAULT_MORELIKE_PLAYGROUND_STATE.interleave,
+  }
+}
+
+function clearStoredState(): void {
+  if (typeof window === 'undefined') return
+
+  try {
+    window.localStorage.removeItem(STORAGE_KEY)
+  } catch {
+    // Private mode or blocked storage — ignore.
+  }
+}
+
+export function loadMorelikePlaygroundState(): MorelikePlaygroundState {
+  if (typeof window === 'undefined') {
+    return { ...DEFAULT_MORELIKE_PLAYGROUND_STATE, mltCustom: { ...DEFAULT_MLT_CUSTOM } }
+  }
+
+  try {
+    const stored = window.localStorage.getItem(STORAGE_KEY)
+    if (!stored) return { ...DEFAULT_MORELIKE_PLAYGROUND_STATE, mltCustom: { ...DEFAULT_MLT_CUSTOM } }
+
+    const parsed: unknown = JSON.parse(stored)
+    const normalized = normalizeState(parsed)
+    persistMorelikePlaygroundState(normalized)
+    return normalized
+  } catch {
+    clearStoredState()
+    return { ...DEFAULT_MORELIKE_PLAYGROUND_STATE, mltCustom: { ...DEFAULT_MLT_CUSTOM } }
+  }
+}
+
+export function persistMorelikePlaygroundState(state: MorelikePlaygroundState): void {
+  if (typeof window === 'undefined') return
+
+  const normalized = normalizeState(state)
+
+  try {
+    window.localStorage.setItem(STORAGE_KEY, JSON.stringify(normalized))
+  } catch {
+    // Quota or private-mode failures — ignore.
+  }
+}