diff --git a/docker-compose.yml b/docker-compose.yml
index c548248..17456bd 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -76,6 +76,7 @@ services:
       SCRAPER_PORT: "8091"
       SCRAPER_TOKEN_FILE: /run/secrets/scraper_token
       SOURCE_PLUGIN_URL: ${SOURCE_PLUGIN_URL:-}
+      MANGADEX_PLUGIN_URL: ${MANGADEX_PLUGIN_URL:-}
     networks: [backend, egress, plugin_backend]
     healthcheck:
       test: [CMD, node, tools/healthcheck.js, scraper]
@@ -126,6 +127,35 @@ services:
     pids_limit: 64
     mem_limit: 256m
     environment:
+      SOURCE_PLUGIN_ID: weebcentral
+      SOURCE_PLUGIN_HOST: 0.0.0.0
+      SOURCE_PLUGIN_PORT: "8094"
+    networks: [plugin_backend]
+    healthcheck:
+      test: [CMD, node, tools/healthcheck-source-plugin.js]
+      interval: 30s
+      timeout: 5s
+      start_period: 15s
+      retries: 3
+
+  source-plugin-mangadex:
+    image: ${APP_IMAGE:-mangacircus:local}
+    build:
+      context: .
+      args:
+        VCS_REF: ${VCS_REF:-development}
+    profiles: [source-plugins]
+    command: [node, scraper/plugins/worker.js]
+    init: true
+    restart: unless-stopped
+    read_only: true
+    tmpfs: [/tmp]
+    security_opt: [no-new-privileges:true]
+    cap_drop: [ALL]
+    pids_limit: 64
+    mem_limit: 256m
+    environment:
+      SOURCE_PLUGIN_ID: mangadex
       SOURCE_PLUGIN_HOST: 0.0.0.0
       SOURCE_PLUGIN_PORT: "8094"
     networks: [plugin_backend]
diff --git a/docs/scraper-service.md b/docs/scraper-service.md
index aa5f84f..756a913 100644
--- a/docs/scraper-service.md
+++ b/docs/scraper-service.md
@@ -7,23 +7,23 @@ proxy commands to its private HTTP API.
 
 ## First-party source parser pilot
 
-The WeebCentral parser is now a reviewed first-party module in
-`scraper/plugins/weebcentral.js`. By default it runs in the scraper process,
-preserving the existing deployment. To test process isolation in Compose, start
-the `source-plugins` profile and set `SOURCE_PLUGIN_URL` for the scraper to
-`http://source-plugin-weebcentral:8094` (for example via the Compose environment).
-Both settings are required; enabling the URL without a healthy worker causes
-WeebCentral discovery to fail closed and retain its checkpoint. Remove the URL
-to roll back. Do not restart a live scraper merely to try this option; use the
-normal checkpoint-safe deployment procedure.
+The WeebCentral and MangaDex parsers have reviewed first-party modules in
+`scraper/plugins/`. By default their existing in-process paths remain in use.
+To test process isolation in Compose, start the `source-plugins` profile and
+set `SOURCE_PLUGIN_URL=http://source-plugin-weebcentral:8094` and/or
+`MANGADEX_PLUGIN_URL=http://source-plugin-mangadex:8094` for the scraper.
+Each URL selects its source independently. A selected worker that is unavailable
+causes that source's discovery to fail closed and retain its checkpoint. Remove
+its URL to roll back. Do not restart a live scraper merely to try this option;
+use the normal checkpoint-safe deployment procedure.
 
-The worker has no published port, egress network, library/data mount, or token.
+Each worker has no published port, egress network, library/data mount, or token.
 Only the existing rate-limited scraper HTTP client fetches remote HTML/images.
 The worker accepts bounded HTML for four parsing steps over its internal-only
 network. It loads only modules listed in the static first-party registry; there
 is no runtime plugin download or execution of Uchiyomi packages. This is a
-parser-isolation pilot, **not yet** a complete generic source-plugin contract,
-or migration of the MangaDex runner. Parsed catalog and image URLs are checked
+parser-isolation pilot, **not yet** a complete generic source-plugin contract
+or migration of either archive runner. Parsed catalog and image URLs are checked
 before use, and parser requests/responses are size-bounded. When the worker is
 enabled, WeebCentral requests use a pinned-DNS HTTPS transport that validates
 each redirect and stops on access errors; the ordinary in-process path is not
diff --git a/scraper/adapters/mangadex.js b/scraper/adapters/mangadex.js
index 9c119ca..2723beb 100644
--- a/scraper/adapters/mangadex.js
+++ b/scraper/adapters/mangadex.js
@@ -2,6 +2,7 @@
 
 const API = 'https://api.mangadex.org';
 const { specialKey } = require('../../chapter-identity');
+const { parseSource } = require('../plugins/client');
 
 function mangaDexInfo(value) {
   let url;
@@ -94,6 +95,10 @@ async function discoverMangaDexCatalog(seriesUrl, http) {
   if (!info) throw new Error('Invalid MangaDex title URL');
   const manga = (await jsonGet(http, `${API}/manga/${info.id}`)).data;
   if (!manga || manga.type !== 'manga') throw new Error('MangaDex title was not found');
+  const isolated = !!process.env.MANGADEX_PLUGIN_URL;
+  const pluginMetadata = isolated
+    ? await parseSource('mangadex', 'metadata', { html: JSON.stringify(manga), url: `${API}/manga/${info.id}` })
+    : null;
 
   const releases = [];
   let offset = 0;
@@ -103,28 +108,37 @@ async function discoverMangaDexCatalog(seriesUrl, http) {
     params.append('includes[]', 'scanlation_group');
     params.append('order[chapter]', 'asc');
     const page = await jsonGet(http, `${API}/manga/${info.id}/feed?${params}`);
-    releases.push(...(page.data || []));
+    if (isolated) {
+      const parsed = await parseSource('mangadex', 'feed', { html: JSON.stringify(page.data || []), url: `${API}/manga/${info.id}/feed` });
+      releases.push(...parsed.releases);
+    } else releases.push(...(page.data || []));
     offset += page.data?.length || 0;
     if (!page.data?.length || offset >= Number(page.total || 0)) break;
   }
 
-  const title = localizedTitle(manga.attributes);
-  const specialLabel = /pre.serialization|pilot/i.test(title) ? 'Pilot'
+  const title = isolated ? pluginMetadata.title : localizedTitle(manga.attributes);
+  const specialLabel = isolated ? pluginMetadata.specialLabel : /pre.serialization|pilot/i.test(title) ? 'Pilot'
     : (manga.attributes?.tags || []).some(tag => tag.attributes?.name?.en === 'Oneshot') ? 'One-shot' : 'Special';
-  const chapters = selectChapterReleases(releases, specialLabel);
+  const pluginCatalog = async externalReleases => parseSource('mangadex', 'catalog', {
+    html: JSON.stringify({ attributes: pluginMetadata.availabilityAttributes, releases, specialLabel, externalReleases }),
+    url: `${API}/manga/${info.id}`,
+  });
+  let parsed = isolated ? await pluginCatalog(null) : null;
+  const chapters = isolated ? parsed.chapters : selectChapterReleases(releases, specialLabel);
   // External-only is a separate feed mode, not a combined hosted+external catalog.
   let externalReleases = null;
   if (!chapters.length) {
     const params = new URLSearchParams({ limit: '1', includeFutureUpdates: '0', includeExternalUrl: '1' });
     params.append('translatedLanguage[]', 'en');
     externalReleases = Number((await jsonGet(http, `${API}/manga/${info.id}/feed?${params}`)).total || 0);
+    if (isolated) parsed = await pluginCatalog(externalReleases);
   }
   return {
     id: info.id,
     title,
-    originalLanguage: manga.attributes?.originalLanguage || null,
-    links: manga.attributes?.links || {},
-    availability: availabilitySummary(manga.attributes || {}, releases, chapters, externalReleases),
+    originalLanguage: isolated ? pluginMetadata.originalLanguage : manga.attributes?.originalLanguage || null,
+    links: isolated ? pluginMetadata.links : manga.attributes?.links || {},
+    availability: isolated ? parsed.availability : availabilitySummary(manga.attributes || {}, releases, chapters, externalReleases),
     chapters,
   };
 }
@@ -147,11 +161,14 @@ function pageUrls(atHome, chapterUrl, expectedPages) {
 async function discoverMangaDexChapter(ref, http) {
   const atHome = await jsonGet(http, `${API}/at-home/server/${ref.id}?forcePort443=true`);
   const groupName = ref.group?.name ? ` · ${ref.group.name}` : '';
+  const parsed = process.env.MANGADEX_PLUGIN_URL
+    ? await parseSource('mangadex', 'atHome', { html: JSON.stringify({ response: atHome, chapterUrl: ref.url, expectedPages: ref.pages }), url: `${API}/at-home/server/${ref.id}` })
+    : null;
   return {
     number: ref.number, title: ref.title || '', added: ref.added,
     ...(ref.special ? { special: true, label: ref.label, sourceId: ref.id, sourceNumber: ref.sourceNumber ?? null } : {}),
     source: { name: `MangaDex${groupName}`, url: ref.url },
-    pages: pageUrls(atHome, ref.url, ref.pages),
+    pages: parsed ? parsed.pages : pageUrls(atHome, ref.url, ref.pages),
   };
 }
 
diff --git a/scraper/plugins/client.js b/scraper/plugins/client.js
index a8c0aee..ddf83cc 100644
--- a/scraper/plugins/client.js
+++ b/scraper/plugins/client.js
@@ -16,7 +16,7 @@ async function boundedJson(response) {
 }
 
 async function parseSource(plugin, operation, input) {
-  const endpoint = process.env.SOURCE_PLUGIN_URL;
+  const endpoint = plugin === 'mangadex' ? process.env.MANGADEX_PLUGIN_URL : process.env.SOURCE_PLUGIN_URL;
   if (!endpoint) return validate(plugin, operation, parse(plugin, operation, input));
   const url = new URL('/v1/parse', endpoint);
   if (!['http:', 'https:'].includes(url.protocol)) throw new Error('Invalid source plugin endpoint');
diff --git a/scraper/plugins/mangadex.js b/scraper/plugins/mangadex.js
new file mode 100644
index 0000000..00ddd37
--- /dev/null
+++ b/scraper/plugins/mangadex.js
@@ -0,0 +1,132 @@
+'use strict';
+
+const { specialKey } = require('../../chapter-identity');
+
+function localizedTitle(attributes = {}) {
+  const titles = attributes.title || {};
+  return titles.en || titles['ja-ro'] || titles.ja || Object.values(titles).find(Boolean) || 'Untitled';
+}
+
+function chapterNumber(value) {
+  const raw = String(value ?? '').trim();
+  if (!/^\d+(?:\.\d+)?$/.test(raw)) return null;
+  const [whole, decimal = ''] = raw.split('.');
+  const normalizedWhole = whole.replace(/^0+(?=\d)/, '') || '0';
+  const normalizedDecimal = decimal.replace(/0+$/, '');
+  return normalizedDecimal ? `${normalizedWhole}.${normalizedDecimal}` : normalizedWhole;
+}
+
+function groupFor(resource) {
+  const relation = (resource.relationships || []).find(item => item.type === 'scanlation_group');
+  return relation ? { id: relation.id, name: relation.attributes?.name || 'Unknown group' } : null;
+}
+
+function releaseRank(resource) {
+  const group = groupFor(resource)?.name || '';
+  const credited = /official|license/i.test(group) ? 0 : group ? 1 : 2;
+  const date = Date.parse(resource.attributes?.publishAt || resource.attributes?.readableAt || resource.attributes?.createdAt || '') || Number.MAX_SAFE_INTEGER;
+  return [credited, date, resource.id];
+}
+
+function compareRank(left, right) {
+  const a = releaseRank(left), b = releaseRank(right);
+  return a[0] - b[0] || a[1] - b[1] || String(a[2]).localeCompare(String(b[2]));
+}
+
+function selectChapterReleases(resources = [], specialLabel = 'Special') {
+  const selected = new Map();
+  for (const resource of resources) {
+    if (resource.attributes?.externalUrl || Number(resource.attributes?.pages || 0) < 1) continue;
+    const number = chapterNumber(resource.attributes?.chapter) || specialKey(resource.id);
+    const prior = selected.get(number);
+    if (!prior || compareRank(resource, prior) < 0) selected.set(number, resource);
+  }
+  return [...selected.entries()].map(([number, resource]) => {
+    const group = groupFor(resource);
+    return {
+      id: resource.id, number, title: resource.attributes?.title || '',
+      ...(!chapterNumber(resource.attributes?.chapter) ? { special: true, label: specialLabel, sourceId: resource.id, sourceNumber: resource.attributes?.chapter ?? null } : {}),
+      ...(resource.attributes?.volume ? { volume: chapterNumber(resource.attributes.volume) || String(resource.attributes.volume) } : {}),
+      pages: Number(resource.attributes?.pages || 0),
+      added: resource.attributes?.publishAt || resource.attributes?.readableAt || resource.attributes?.createdAt,
+      group,
+      url: `https://mangadex.org/chapter/${resource.id}`,
+    };
+  }).sort((a, b) => Number(!!a.special) - Number(!!b.special) || (a.special ? a.number.localeCompare(b.number) : Number(a.number) - Number(b.number) || a.number.localeCompare(b.number)));
+}
+
+function availabilitySummary(attributes, releases, chapters, externalReleases = null) {
+  const numbered = chapters.filter(ref => !ref.special);
+  const expected = chapterNumber(attributes.lastChapter);
+  const maximum = numbered.length ? Math.max(...numbered.map(ref => Number(ref.number))) : null;
+  const expectedCount = expected && /^\d+$/.test(expected) ? Number(expected) : null;
+  const sparse = expectedCount && numbered.length < expectedCount;
+  const reason = chapters.length ? null : externalReleases > 0 ? 'external-only'
+    : Array.isArray(attributes.availableTranslatedLanguages) && !attributes.availableTranslatedLanguages.includes('en') ? 'no-english' : 'no-hosted-pages';
+  const message = reason === 'external-only' ? `MangaDex lists ${externalReleases} English external-link releases, but no hosted English pages. External links are not downloaded.`
+    : reason === 'no-english' ? 'This MangaDex edition has no English releases listed.'
+      : reason ? 'This MangaDex edition has no hosted English releases with pages.' : null;
+  return { language: 'en', hostedReleases: releases.filter(r => !r.attributes?.externalUrl && Number(r.attributes?.pages) > 0).length,
+    selectedChapters: chapters.length, numberedChapters: numbered.length, specialReleases: chapters.length - numbered.length,
+    externalReleases, expectedLastChapter: expected, highestHostedChapter: maximum,
+    coverage: expected && (maximum === null || maximum < Number(expected) || sparse) ? 'partial' : 'unknown', reason, message };
+}
+
+function pageUrls(atHome, chapterUrl, expectedPages) {
+  const base = new URL(atHome.baseUrl);
+  if (base.protocol !== 'https:' || !(base.hostname === 'uploads.mangadex.org' || base.hostname.endsWith('.mangadex.network'))) {
+    throw new Error(`Unexpected MangaDex@Home host: ${base.hostname}`);
+  }
+  const hash = String(atHome.chapter?.hash || '');
+  const files = atHome.chapter?.data;
+  if (!hash || !Array.isArray(files) || !files.length) throw new Error('MangaDex@Home returned no pages');
+  if (expectedPages && files.length !== expectedPages) throw new Error(`MangaDex page count changed: expected ${expectedPages}, received ${files.length}`);
+  return files.map(file => ({
+    url: new URL(`/data/${encodeURIComponent(hash)}/${encodeURIComponent(file)}`, base).href,
+    headers: { referer: chapterUrl },
+  }));
+}
+
+function metadata({ html }) {
+  const manga = JSON.parse(html);
+  if (!manga || manga.type !== 'manga') throw new Error('MangaDex title was not found');
+  const attributes = manga.attributes || {};
+  const title = localizedTitle(attributes);
+  const specialLabel = /pre.serialization|pilot/i.test(title) ? 'Pilot'
+    : (attributes.tags || []).some(tag => tag.attributes?.name?.en === 'Oneshot') ? 'One-shot' : 'Special';
+  return { title, originalLanguage: attributes.originalLanguage || null, links: attributes.links || {},
+    specialLabel, availabilityAttributes: {
+      lastChapter: attributes.lastChapter ?? null,
+      availableTranslatedLanguages: attributes.availableTranslatedLanguages ?? null,
+    } };
+}
+
+function feed({ html }) {
+  const releases = JSON.parse(html);
+  if (!Array.isArray(releases)) throw new Error('Invalid MangaDex feed');
+  return { releases: releases.map(resource => ({
+    id: resource.id,
+    attributes: {
+      chapter: resource.attributes?.chapter, volume: resource.attributes?.volume,
+      title: resource.attributes?.title, pages: resource.attributes?.pages,
+      publishAt: resource.attributes?.publishAt, readableAt: resource.attributes?.readableAt,
+      createdAt: resource.attributes?.createdAt, externalUrl: resource.attributes?.externalUrl,
+    },
+    relationships: (resource.relationships || []).filter(relation => relation.type === 'scanlation_group'),
+  })) };
+}
+
+function catalog({ html }) {
+  const { attributes, releases, specialLabel, externalReleases } = JSON.parse(html);
+  if (!attributes || !Array.isArray(releases)) throw new Error('Invalid MangaDex catalog input');
+  const chapters = selectChapterReleases(releases, specialLabel);
+  return { chapters, availability: availabilitySummary(attributes, releases, chapters, externalReleases) };
+}
+
+function atHome({ html }) {
+  const { response, chapterUrl, expectedPages } = JSON.parse(html);
+  return { pages: pageUrls(response, chapterUrl, expectedPages) };
+}
+
+module.exports = { localizedTitle, chapterNumber, selectChapterReleases, availabilitySummary,
+  pageUrls, metadata, feed, catalog, atHome };
diff --git a/scraper/plugins/manifest.js b/scraper/plugins/manifest.js
index e547079..524acf3 100644
--- a/scraper/plugins/manifest.js
+++ b/scraper/plugins/manifest.js
@@ -10,6 +10,13 @@ const manifests = Object.freeze({
     provenance: 'MangaCircus existing WeebCentral adapter; no Uchiyomi code copied',
     operations: Object.freeze(['series', 'catalog', 'chapter', 'pages']),
   }),
+  mangadex: Object.freeze({
+    id: 'mangadex', version: 1, label: 'MangaDex', status: 'pilot',
+    sourceHosts: Object.freeze(['api.mangadex.org']),
+    implementation: 'first-party',
+    provenance: 'MangaCircus existing MangaDex adapter; no Uchiyomi code copied',
+    operations: Object.freeze(['metadata', 'feed', 'catalog', 'atHome']),
+  }),
 });
 
 module.exports = { manifests };
diff --git a/scraper/plugins/registry.js b/scraper/plugins/registry.js
index eca7382..fb2a6f7 100644
--- a/scraper/plugins/registry.js
+++ b/scraper/plugins/registry.js
@@ -2,7 +2,10 @@
 
 // Reviewed first-party modules only. No filesystem scanning or runtime installs.
 const { manifests } = require('./manifest');
-const plugins = Object.freeze({ weebcentral: require('./weebcentral') });
+const plugins = Object.freeze({
+  weebcentral: require('./weebcentral'),
+  mangadex: require('./mangadex'),
+});
 
 function parse(plugin, operation, input) {
   const manifest = manifests[plugin];
diff --git a/scraper/plugins/validation.js b/scraper/plugins/validation.js
index 7af082c..b1d4b01 100644
--- a/scraper/plugins/validation.js
+++ b/scraper/plugins/validation.js
@@ -21,10 +21,36 @@ function imageUrl(value) {
   return url.href;
 }
 
+function mangaDexUrl(value, kind) {
+  const url = new URL(value);
+  if (url.protocol !== 'https:' || url.username || url.password || url.port) throw new Error('Invalid MangaDex plugin URL');
+  if (kind === 'chapter' && (url.hostname !== 'mangadex.org' || !url.pathname.startsWith('/chapter/'))) {
+    throw new Error('Unexpected MangaDex chapter URL');
+  }
+  if (kind === 'page' && !(url.hostname === 'uploads.mangadex.org' || url.hostname.endsWith('.mangadex.network'))) {
+    throw new Error('Unexpected MangaDex page host');
+  }
+  return url.href;
+}
+
 function validate(plugin, operation, output) {
-  if (plugin !== 'weebcentral' || !output || typeof output !== 'object' || Array.isArray(output)) {
+  if (!['weebcentral', 'mangadex'].includes(plugin) || !output || typeof output !== 'object' || Array.isArray(output)) {
     throw new Error('Invalid source plugin output');
   }
+  if (plugin === 'mangadex') {
+    if (operation === 'metadata') {
+      if (typeof output.title !== 'string' || !output.availabilityAttributes || typeof output.specialLabel !== 'string') throw new Error('Invalid MangaDex metadata');
+    } else if (operation === 'feed') {
+      if (!Array.isArray(output.releases) || output.releases.some(ref => typeof ref?.id !== 'string' || !ref.attributes)) throw new Error('Invalid MangaDex feed');
+    } else if (operation === 'catalog') {
+      if (!Array.isArray(output.chapters) || !output.availability) throw new Error('Invalid MangaDex catalog');
+      for (const chapter of output.chapters) mangaDexUrl(chapter.url, 'chapter');
+    } else if (operation === 'atHome') {
+      if (!Array.isArray(output.pages) || !output.pages.length) throw new Error('Invalid MangaDex pages');
+      for (const page of output.pages) mangaDexUrl(page.url, 'page');
+    } else throw new Error('Unknown source plugin operation');
+    return output;
+  }
   if (operation === 'series') {
     if (typeof output.title !== 'string' || typeof output.listUrl !== 'string' && output.listUrl !== null) throw new Error('Invalid series parse');
     if (output.listUrl !== null) sourceUrl(output.listUrl, '/series/');
diff --git a/scraper/plugins/worker.js b/scraper/plugins/worker.js
index 7858910..aa737be 100644
--- a/scraper/plugins/worker.js
+++ b/scraper/plugins/worker.js
@@ -4,7 +4,7 @@ const http = require('node:http');
 const { parse } = require('./registry');
 const MAX_BODY_BYTES = 2 * 1024 * 1024;
 
-function createServer() {
+function createServer(pluginId = process.env.SOURCE_PLUGIN_ID || null) {
   return http.createServer((request, response) => {
     if (request.method === 'GET' && request.url === '/health') {
       response.writeHead(200, { 'content-type': 'application/json' });
@@ -30,6 +30,7 @@ function createServer() {
       if (bytes > MAX_BODY_BYTES) return;
       try {
         const { plugin, operation, input } = JSON.parse(Buffer.concat(chunks).toString('utf8'));
+        if (pluginId && plugin !== pluginId) throw new Error('Plugin worker does not serve this source');
         const output = parse(plugin, operation, input);
         response.writeHead(200, { 'content-type': 'application/json' });
         response.end(JSON.stringify(output));
diff --git a/scraper/test/source-mangadex-plugin.test.js b/scraper/test/source-mangadex-plugin.test.js
new file mode 100644
index 0000000..0584b2b
--- /dev/null
+++ b/scraper/test/source-mangadex-plugin.test.js
@@ -0,0 +1,55 @@
+'use strict';
+
+const test = require('node:test');
+const assert = require('node:assert/strict');
+const { createServer } = require('../plugins/worker');
+const { discoverMangaDexCatalog, discoverMangaDexChapter } = require('../adapters/mangadex');
+
+const mangaId = '123e4567-e89b-42d3-a456-426614174000';
+const chapterIds = [
+  '123e4567-e89b-42d3-a456-426614174001',
+  '123e4567-e89b-42d3-a456-426614174002',
+];
+const seriesUrl = `https://mangadex.org/title/${mangaId}/Fixture`;
+const manga = { data: { type: 'manga', attributes: {
+  title: { en: 'Fixture' }, originalLanguage: 'ja', lastChapter: '2',
+  availableTranslatedLanguages: ['en'], links: {}, tags: [],
+} } };
+const feed = { total: 2, data: chapterIds.map((id, index) => ({
+  id, attributes: { chapter: String(index + 1), title: `Part ${index + 1}`, pages: 2,
+    publishAt: `2026-01-0${index + 1}T00:00:00Z` }, relationships: [],
+})) };
+
+function fakeHttp() {
+  return { async get(url) {
+    const body = url.includes('/at-home/server/') ? {
+      baseUrl: 'https://uploads.mangadex.org', chapter: { hash: 'HASH', data: ['1.jpg', '2.jpg'] },
+    } : url.includes('/feed?') ? feed : manga;
+    return { json: async () => body };
+  } };
+}
+
+test('MangaDex isolated parser matches the existing catalog and page behavior', async () => {
+  const server = createServer('mangadex');
+  await new Promise(resolve => server.listen(0, '127.0.0.1', resolve));
+  const previous = process.env.MANGADEX_PLUGIN_URL;
+  delete process.env.MANGADEX_PLUGIN_URL;
+  try {
+    const baseline = await discoverMangaDexCatalog(seriesUrl, fakeHttp());
+    const baselineChapter = await discoverMangaDexChapter(baseline.chapters[0], fakeHttp());
+    process.env.MANGADEX_PLUGIN_URL = `http://127.0.0.1:${server.address().port}`;
+    const isolated = await discoverMangaDexCatalog(seriesUrl, fakeHttp());
+    const isolatedChapter = await discoverMangaDexChapter(isolated.chapters[0], fakeHttp());
+    assert.deepEqual(isolated, baseline);
+    assert.deepEqual(isolatedChapter, baselineChapter);
+    const rejected = await fetch(`${process.env.MANGADEX_PLUGIN_URL}/v1/parse`, {
+      method: 'POST', headers: { 'content-type': 'application/json' },
+      body: JSON.stringify({ plugin: 'weebcentral', operation: 'series', input: { html: '<h1>X</h1>', url: 'https://weebcentral.com/series/X' } }),
+    });
+    assert.equal(rejected.status, 400);
+  } finally {
+    if (previous === undefined) delete process.env.MANGADEX_PLUGIN_URL;
+    else process.env.MANGADEX_PLUGIN_URL = previous;
+    await new Promise(resolve => server.close(resolve));
+  }
+});
diff --git a/vision/first-party-source-plugins.md b/vision/first-party-source-plugins.md
index 79dabfc..f3570c9 100644
--- a/vision/first-party-source-plugins.md
+++ b/vision/first-party-source-plugins.md
@@ -9,6 +9,9 @@ to do; the diagram describes the target rather than the current implementation.
 Parser-result URL validation and bounded worker messages were added next. The
 opt-in WeebCentral path now validates redirect hops and pins public DNS answers;
 source-specific image CDN allowlists and generic broker integration remain pending.
+MangaDex metadata, feed selection, catalog availability, and at-home page parsing
+now have a second opt-in worker path with fixture parity; its transport still
+uses the existing API client and runner.
 
 ## Decision