diff --git a/tests/embeds.test.ts b/tests/embeds.test.ts
index 819e4d1..d784c7f 100644
--- a/tests/embeds.test.ts
+++ b/tests/embeds.test.ts
@@ -118,3 +118,58 @@ test('the editor corpus embed entries expand after sanitizing', () => {
     assert.equal(expandEmbeds(clean), clean, entry.name)
   }
 })
+
+test('expansion is last: sanitizing the expanded output would strip the iframe', () => {
+  // Why the order matters: the sanitizer never keeps an iframe, so a sink that
+  // sanitized after expanding would lose every video.
+  const again = sanitizeJournalHtml(IFRAME)
+  assert.equal(iframeCount(again), 0)
+  assert.doesNotMatch(again, /youtube-nocookie/)
+})
+
+test('the sinks expand after sanitizing and the payload transforms never expand', () => {
+  const read = (path: string) => readFileSync(new URL(path, import.meta.url), 'utf8')
+  for (const sink of ['../app/components/Journal/PostBody.vue', '../app/components/Journal/CategoryHeader.vue']) {
+    const source = read(sink)
+    assert.match(source, /expandEmbeds\(sanitizeJournalHtml\(/, `${sink} must render expandEmbeds(sanitizeJournalHtml(...))`)
+    assert.equal((source.match(/expandEmbeds\(/g) ?? []).length, 1, `${sink} expands once`)
+  }
+  for (const transform of ['../app/utils/postView.ts', '../app/journal-pages/CategoryPage.vue']) {
+    assert.doesNotMatch(read(transform), /expandEmbeds/, `${transform} must not expand`)
+  }
+})
+
+test('only the exact serialization expands: case, spacing and entities stay inert', () => {
+  const inert = [
+    `<figure data-embed="YouTube" data-id="${ID}"></figure>`,
+    `<figure data-embed="youtube " data-id="${ID}"></figure>`,
+    `<figure  data-embed="youtube" data-id="${ID}"></figure>`,
+    `<figure data-embed="youtube" data-id="${ID}" ></figure>`,
+    `<FIGURE data-embed="youtube" data-id="${ID}"></FIGURE>`,
+    `<figure data-embed="youtube" data-id="javascript:1"></figure>`,
+    `<figure data-embed="youtube" data-id="dQw4w9WgXc&#81;"></figure>`,
+    `<figure data-embed="youtube" data-id="${ID}">\n</figure>`,
+    `<figure data-embed="youtube" data-id=""></figure>`,
+  ]
+  for (const html of inert) {
+    assert.equal(expandEmbeds(html), html, html)
+    assert.equal(iframeCount(expandEmbeds(html)), 0, html)
+  }
+})
+
+test('expansion is stable across calls (the global pattern keeps no state)', () => {
+  const body = `<p>a</p>${PLACEHOLDER}<p>b</p>${PLACEHOLDER}`
+  const first = expandEmbeds(body)
+  assert.equal(expandEmbeds(body), first)
+  assert.equal(EMBED_PLACEHOLDER.lastIndex, 0)
+  assert.equal(iframeCount(first), 2)
+})
+
+test('the iframe src is a fixed host plus the validated id, never stored text', () => {
+  const out = sink(`<figure data-embed="youtube" data-id="${ID}"></figure>`)
+  const src = /<iframe src="([^"]+)"/.exec(out)?.[1]
+  assert.equal(src, `https://www.youtube-nocookie.com/embed/${ID}`)
+  assert.match(out, /referrerpolicy="strict-origin-when-cross-origin"/)
+  assert.match(out, /loading="lazy"/)
+  assert.doesNotMatch(out, /allow="[^"]*(autoplay|camera|microphone|geolocation)/)
+})
diff --git a/tests/htmlGate.test.ts b/tests/htmlGate.test.ts
index 843f19d..9304666 100644
--- a/tests/htmlGate.test.ts
+++ b/tests/htmlGate.test.ts
@@ -292,3 +292,44 @@ test('img alt keeps free text with a colon, a question mark and quotes', () => {
   // area alt keeps the UGC pattern; only img alt is widened.
   assert.equal(sanitizeJournalHtml('<map name="m"><area alt="a: b?" href="/x" /></map>'), '<map name="m"><area href="/x" /></map>')
 })
+
+test('the four editor rules accept exactly the editor values (D-05 amended mirror)', () => {
+  const kept = [
+    PLACEHOLDER,
+    '<p><img src="/a.jpg" alt="any text: with ? and &quot;quotes&quot;" /></p>',
+    '<ol start="1"><li>a</li></ol>',
+    '<ol start="42"><li>a</li></ol>',
+  ]
+  for (const html of kept) {
+    assert.equal(sanitizeJournalHtml(html), html, html)
+    assert.equal(isSafeJournalHtml(html), true, html)
+  }
+})
+
+test('the Go policy negatives are stripped the same way here', () => {
+  const cases: Array<[string, string, string]> = [
+    ['upper-case provider', '<figure data-embed="YouTube" data-id="dQw4w9WgXcQ"></figure>', '<figure data-id="dQw4w9WgXcQ"></figure>'],
+    ['provider with a suffix', '<figure data-embed="youtube2" data-id="dQw4w9WgXcQ"></figure>', '<figure data-id="dQw4w9WgXcQ"></figure>'],
+    ['empty id', '<figure data-embed="youtube" data-id=""></figure>', '<figure data-embed="youtube"></figure>'],
+    ['id with a URL', '<figure data-embed="youtube" data-id="javascript:1"></figure>', '<figure data-embed="youtube"></figure>'],
+    ['id with a space', '<figure data-embed="youtube" data-id="dQw4w9 gXcQ"></figure>', '<figure data-embed="youtube"></figure>'],
+    ['embed attributes on p', '<p data-embed="youtube" data-id="dQw4w9WgXcQ">x</p>', '<p>x</p>'],
+    ['embed attributes on a', '<a href="/x" data-embed="youtube" data-id="dQw4w9WgXcQ">x</a>', '<a href="/x">x</a>'],
+    ['data attribute alone on figure', '<figure data-url="https://evil.test/"></figure>', '<figure></figure>'],
+    ['script inside the placeholder', '<figure data-embed="youtube" data-id="dQw4w9WgXcQ"><script>alert(1)</script></figure>', PLACEHOLDER],
+    ['iframe alone', '<iframe src="https://www.youtube-nocookie.com/embed/dQw4w9WgXcQ"></iframe>', ''],
+    ['start with a fraction', '<ol start="1.5"><li>a</li></ol>', '<ol><li>a</li></ol>'],
+    ['alt on p', '<p alt="x">y</p>', '<p>y</p>'],
+  ]
+  for (const [name, html, want] of cases) {
+    assert.equal(sanitizeJournalHtml(html), want, name)
+    assert.equal(isSafeJournalHtml(html), false, `${name} reported safe`)
+  }
+})
+
+test('every corpus entry stays free of danger after the sink pipeline', () => {
+  for (const entry of CORPUS) {
+    const out = sanitizeJournalHtml(sanitizeJournalHtml(entry.html))
+    for (const pattern of DANGER) assert.doesNotMatch(out, pattern, `${entry.name}: ${pattern}`)
+  }
+})