@@ -168,8 +168,8 @@ function guardParagraphLeading(text: string): string {
  * paragraph renders as just its inline children; this override wraps that with the leading guard.
  */
 const BlockSafeParagraph = Paragraph.extend({
-  parseMarkdown: (token, helpers) => {
-    const parsed = Paragraph.config.parseMarkdown?.(token, helpers) ?? []
+  parseMarkdown(token, helpers) {
+    const parsed = this.parent?.(token, helpers) ?? []
     return Array.isArray(parsed) ? parsed : splitBlockImageParagraph(parsed)
   },
   renderMarkdown: (node: JSONContent, h, context) => {
@@ -271,8 +271,8 @@ export function createMarkdownContentExtensions(
     nodeViews.mention ?? MarkdownMention,
     TaskList,
     TaskItem.extend({
-      parseMarkdown: (token, helpers) => {
-        const parsed = TaskItem.config.parseMarkdown?.(token, helpers) ?? []
+      parseMarkdown(token, helpers) {
+        const parsed = this.parent?.(token, helpers) ?? []
         if (Array.isArray(parsed)) return parsed
         const content = (parsed.content ?? []).flatMap(splitBlockImageParagraph)
         if (content[0]?.type !== 'paragraph') content.unshift({ type: 'paragraph' })
 
@@ -57,6 +57,10 @@ async function render(
   )
   await act(async () => vi.advanceTimersByTimeAsync(10))
 }
+
+/** ProseMirror buffers inline atoms at a block start with an empty separator `<img>`. */
+const RENDERED_IMAGE = 'img:not(.ProseMirror-separator)'
+
 function editor() {
   return host.querySelector<HTMLElement & { editor: Editor }>('.tiptap')!.editor
 }
@@ -116,9 +120,9 @@ describe('field upload completion boundary', () => {
       expect(host.querySelector('strong')?.textContent).toBe('Tail')
       expect(host.querySelector('a')?.getAttribute('href')).toBe('/destination')
       expect(
-        Array.from(host.querySelectorAll('img')).map((image) => image.getAttribute('src'))
+        Array.from(host.querySelectorAll(RENDERED_IMAGE)).map((image) => image.getAttribute('src'))
       ).toEqual(['/api/files/view/uploaded', '/other.png'])
-      expect(host.querySelector('img')?.getAttribute('alt')).toBe('Original alt')
+      expect(host.querySelector(RENDERED_IMAGE)?.getAttribute('alt')).toBe('Original alt')
       expect(owner.getMarkdown()).toContain('width="123"')
       expect(owner.getMarkdown()).not.toContain('/inline?')
       expect(() => owner.state.doc.check()).not.toThrow()
@@ -151,7 +155,7 @@ describe('field upload completion boundary', () => {
       expect(upload).not.toHaveBeenCalled()
       expect(host.querySelector('h2')?.textContent).toBe('Caption')
       expect(owner.state.doc.textContent).toContain('Tail')
-      expect(Array.from(host.querySelectorAll('img')).map((image) => image.alt)).toEqual([
+      expect(Array.from(host.querySelectorAll<HTMLImageElement>(RENDERED_IMAGE)).map((image) => image.alt)).toEqual([
         'One',
         'Two',
       ])
 
@@ -217,7 +217,7 @@ describe.each([
     expect(editor.getText()).toBe(`Prefix ${source}\n\nAfter`)
   })
 
-  it('undoes a collaborative conversion without removing peer text', () => {
+  it('undoes a collaborative conversion to its source, then the input, without removing peer text', () => {
     const seed = markdownToYDoc('TARGET\n\nAfter')
     const a = createPeer(seed)
     const b = createPeer(seed)
@@ -232,9 +232,14 @@ describe.each([
     Y.applyUpdate(a.doc, Y.encodeStateAsUpdate(b.doc))
     expect(a.editor.commands.undo()).toBe(true)
     Y.applyUpdate(b.doc, Y.encodeStateAsUpdate(a.doc))
+    expect(a.editor.getText()).toBe(`Prefix ${source}\n\nPeer text`)
+    expect(b.editor.getJSON()).toEqual(a.editor.getJSON())
+    expect(a.editor.commands.undo()).toBe(true)
+    Y.applyUpdate(b.doc, Y.encodeStateAsUpdate(a.doc))
     expect(a.editor.getText()).toBe('TARGET\n\nPeer text')
     expect(b.editor.getJSON()).toEqual(a.editor.getJSON())
     expect(a.editor.commands.redo()).toBe(true)
+    expect(a.editor.commands.redo()).toBe(true)
     Y.applyUpdate(b.doc, Y.encodeStateAsUpdate(a.doc))
     assertConverted(a.editor)
     expect(a.editor.getText()).toContain('Peer text')
 
@@ -5,7 +5,6 @@ import { Plugin } from '@tiptap/pm/state'
 import { Lexer, Tokenizer } from 'marked'
 import { imageTypeAt } from '@/app/workspace/[workspaceId]/files/components/file-viewer/rich-markdown-editor/image-node'
 import { normalizeLinkHref } from '@/app/workspace/[workspaceId]/files/components/file-viewer/rich-markdown-editor/markdown-fidelity'
-import { createTextInputRulePlugins } from '@/app/workspace/[workspaceId]/files/components/file-viewer/rich-markdown-editor/text-input-rule'
 
 /**
  * React-free schema half of the image node. Lives apart from {@link ./image} (its React resize node
@@ -187,10 +186,8 @@ const ImageSchema = Image.extend({
 })
 
 export const MarkdownImage = ImageSchema.extend({
-  addProseMirrorPlugins() {
-    return createTextInputRulePlugins(
-      this.editor,
-      this.name,
+  addInputRules() {
+    return [
       new InputRule({
         find: new RegExp(`${inputRegex.source}(?![\\s\\S])`),
         handler: ({ state, range, match }) => {
@@ -201,8 +198,8 @@ export const MarkdownImage = ImageSchema.extend({
             .replaceRangeWith(from, range.to, type.create({ alt, src, title: title ?? null }))
             .scrollIntoView()
         },
-      })
-    )
+      }),
+    ]
   },
   addCommands() {
     return {
 
@@ -1,6 +1,5 @@
 import { Extension, InputRule } from '@tiptap/core'
 import { normalizeLinkHref } from '@/app/workspace/[workspaceId]/files/components/file-viewer/rich-markdown-editor/markdown-fidelity'
-import { createTextInputRulePlugins } from '@/app/workspace/[workspaceId]/files/components/file-viewer/rich-markdown-editor/text-input-rule'
 
 /**
  * Typed markdown link: `[text](url)` or `[text](url "title")`, completed by the closing `)`. The URL
@@ -20,10 +19,8 @@ const LINK_INPUT_RULE = /(?<!!)\[([^\]]+)]\(([^)\s]+)(?:\s+"([^"]*)")?\)(?![\s\S
 export const MarkdownLinkInputRule = Extension.create({
   name: 'markdownLinkInputRule',
 
-  addProseMirrorPlugins() {
-    return createTextInputRulePlugins(
-      this.editor,
-      this.name,
+  addInputRules() {
+    return [
       new InputRule({
         find: LINK_INPUT_RULE,
         handler: ({ state, range, match }) => {
@@ -41,7 +38,7 @@ export const MarkdownLinkInputRule = Extension.create({
           tr.addMark(range.from, markEnd, linkType.create({ href, title: title || null }))
           tr.removeStoredMark(linkType)
         },
-      })
-    )
+      }),
+    ]
   },
 })
@@ -1,20 +1,32 @@
-import { ListItem } from '@tiptap/extension-list'
+import { type RenderContext, renderNestedMarkdownContent } from '@tiptap/core'
+import { getListMarker, ListItem } from '@tiptap/extension-list'
 import { splitBlockImageParagraph } from '@/app/workspace/[workspaceId]/files/components/file-viewer/rich-markdown-editor/block-image-paragraph'
 
+function listItemMarker(context: RenderContext): string {
+  if (context.parentType !== 'orderedList') return '- '
+  const { start, type } = context.meta?.parentAttrs ?? {}
+  const first = (typeof start === 'number' && start) || 1
+  return getListMarker(typeof type === 'string' ? type : null, first - 1 + context.index, '. ')
+}
+
 /**
  * Markdown items may start with a nested block, but the list-item schema requires a paragraph
  * first. Supply that empty paragraph before Yjs hydration can discard the invalid subtree.
+ *
+ * Nested blocks keep the two-space indent under every marker. Upstream aligns ordered-item
+ * children to the marker width, but its ordered-list tokenizer strips one column less, so a
+ * fenced code block inside a numbered item would gain a leading space on every save.
  */
 export const MarkdownListItem = ListItem.extend({
-  parseMarkdown: (token, helpers) => {
-    const parsed = ListItem.config.parseMarkdown?.(token, helpers) ?? []
+  parseMarkdown(token, helpers) {
+    const parsed = this.parent?.(token, helpers) ?? []
     if (Array.isArray(parsed)) return parsed
     const content = (parsed.content ?? []).flatMap(splitBlockImageParagraph)
     if (content[0]?.type !== 'paragraph') content.unshift({ type: 'paragraph' })
     return { ...parsed, content }
   },
   renderMarkdown: (node, helpers, context) => {
-    const rendered = ListItem.config.renderMarkdown?.(node, helpers, context) ?? ''
+    const rendered = renderNestedMarkdownContent(node, helpers, listItemMarker(context))
     /** Marked misreads an opening empty `- ` line as prose when it has a trailing space. */
     return rendered.replace(/^-[ \t]+(?=\n|$)/, '-')
   },
 
@@ -14,16 +14,15 @@ import { excludeTableBlockInputRules } from '@/app/workspace/[workspaceId]/files
  */
 export function createJoiningOrderedList() {
   const delimiters = new WeakMap<JSONContent, '.' | ')'>()
-  const parse = OrderedList.config.parseMarkdown
 
   return OrderedList.extend({
     addInputRules() {
       return excludeTableBlockInputRules(
         joinListInputRules(this.parent?.() ?? [], this.type, { compatible: orderedListContinues })
       )
     },
-    parseMarkdown: (token, helpers) => {
-      if (!token.ordered || !token.items?.length) return parse?.(token, helpers) ?? []
+    parseMarkdown(token, helpers) {
+      if (!token.ordered || !token.items?.length) return this.parent?.(token, helpers) ?? []
 
       /**
        * The upstream tokenizer retains each item's raw marker but ignores delimiter changes.
@@ -61,7 +60,7 @@ export function createJoiningOrderedList() {
           ),
         })),
       }
-      const parsedList = parse?.(resolved, helpers) ?? []
+      const parsedList = this.parent?.(resolved, helpers) ?? []
       if (Array.isArray(parsedList)) return parsedList
       /** Use the registered item parser so empty items retain their schema-required paragraph. */
       const parsed = { ...parsedList, content: helpers.parseChildren(resolved.items) }
 
@@ -167,7 +167,13 @@ describe('isRoundTripSafe', () => {
   })
 
   it('rejects non-idempotent churn', () => {
-    expect(isRoundTripSafe('render `` a`b `` inline')).toBe(false)
+    expect(isRoundTripSafe('10. ten\n    ```\n    code\n    ```')).toBe(false)
+  })
+
+  it('keeps fenced code inside a numbered item editable and byte-stable', () => {
+    const source = '1. step\n  ```\n  code\n  ```\n2. next\n'
+    expect(serializeMarkdownDocument(source)).toBe(source)
+    expect(isRoundTripSafe(source)).toBe(true)
   })
 
   it('keeps HTML images with unsupported attributes in source mode', () => {
 
@@ -142,23 +142,23 @@
     "@t3-oss/env-nextjs": "0.13.11",
     "@tanstack/react-query": "5.90.8",
     "@tanstack/react-virtual": "3.13.24",
-    "@tiptap/core": "3.30.5",
-    "@tiptap/extension-code": "3.30.5",
-    "@tiptap/extension-code-block": "3.30.5",
-    "@tiptap/extension-collaboration": "3.30.5",
-    "@tiptap/extension-collaboration-caret": "3.30.5",
-    "@tiptap/extension-document": "3.30.5",
-    "@tiptap/extension-hard-break": "3.30.5",
-    "@tiptap/extension-image": "3.30.5",
-    "@tiptap/extension-list": "3.30.5",
-    "@tiptap/extension-paragraph": "3.30.5",
-    "@tiptap/extension-placeholder": "3.30.5",
-    "@tiptap/extension-table": "3.30.5",
-    "@tiptap/markdown": "3.30.5",
-    "@tiptap/pm": "3.30.5",
-    "@tiptap/react": "3.30.5",
-    "@tiptap/starter-kit": "3.30.5",
-    "@tiptap/suggestion": "3.30.5",
+    "@tiptap/core": "3.31.4",
+    "@tiptap/extension-code": "3.31.4",
+    "@tiptap/extension-code-block": "3.31.4",
+    "@tiptap/extension-collaboration": "3.31.4",
+    "@tiptap/extension-collaboration-caret": "3.31.4",
+    "@tiptap/extension-document": "3.31.4",
+    "@tiptap/extension-hard-break": "3.31.4",
+    "@tiptap/extension-image": "3.31.4",
+    "@tiptap/extension-list": "3.31.4",
+    "@tiptap/extension-paragraph": "3.31.4",
+    "@tiptap/extension-placeholder": "3.31.4",
+    "@tiptap/extension-table": "3.31.4",
+    "@tiptap/markdown": "3.31.4",
+    "@tiptap/pm": "3.31.4",
+    "@tiptap/react": "3.31.4",
+    "@tiptap/starter-kit": "3.31.4",
+    "@tiptap/suggestion": "3.31.4",
     "@tiptap/y-tiptap": "3.0.7",
     "@trigger.dev/core": "4.5.16",
     "@trigger.dev/sdk": "4.5.16",