diff --git a/src/onenote/one/content.ts b/src/onenote/one/content.ts
index 32de66e..bb33091 100644
--- a/src/onenote/one/content.ts
+++ b/src/onenote/one/content.ts
@@ -54,6 +54,7 @@ import {
 export interface OneNoteContentBudget {
   blocks: number;
   textRuns: number;
+  textCharacters: number;
   tableCells: number;
   inkPoints: number;
 }
@@ -72,7 +73,13 @@ interface ContentContext extends OneNoteContentParseOptions {
 }
 
 export function createContentBudget(): OneNoteContentBudget {
-  return { blocks: 0, textRuns: 0, tableCells: 0, inkPoints: 0 };
+  return {
+    blocks: 0,
+    textRuns: 0,
+    textCharacters: 0,
+    tableCells: 0,
+    inkPoints: 0,
+  };
 }
 
 /** Parse page graph roots into an inert, recursively structured content tree. */
@@ -235,6 +242,7 @@ function parseRichText(
   let sourceText = optionalString(object, PROPERTY.RichEditTextUnicode);
   sourceText ??= optionalLatin1(object, PROPERTY.TextExtendedAscii);
   sourceText = (sourceText ?? '').split('\0').join('');
+  incrementTextCharacterBudget(context, sourceText.length);
 
   const paragraphStyleId = objectReferences(object, PROPERTY.ParagraphStyle)[0];
   const paragraphStyle = paragraphStyleId
@@ -1223,6 +1231,22 @@ function incrementTextRunBudget(context: ContentContext, amount: number): void {
   }
 }
 
+function incrementTextCharacterBudget(
+  context: ContentContext,
+  amount: number
+): void {
+  const next = context.budget.textCharacters + amount;
+  if (
+    !Number.isSafeInteger(next) ||
+    next > context.limits.maxExtractedTextChars
+  ) {
+    throw new Error(
+      `Rich-text character count exceeds ${context.limits.maxExtractedTextChars}`
+    );
+  }
+  context.budget.textCharacters = next;
+}
+
 function incrementTableCellBudget(context: ContentContext): void {
   context.budget.tableCells += 1;
   if (context.budget.tableCells > context.limits.maxTableCells) {
diff --git a/tests/content-model.test.ts b/tests/content-model.test.ts
index a019cb0..b5eaf82 100644
--- a/tests/content-model.test.ts
+++ b/tests/content-model.test.ts
@@ -14,6 +14,7 @@ import {
   type OneNoteContentBlock,
   type OneNoteTextBlock,
 } from '../src/onenote/index.js';
+import type { ParserDiagnostic } from '../src/onenote/model/diagnostics.js';
 import { parseContentObjects } from '../src/onenote/one/content.js';
 import { JCID, PROPERTY } from '../src/onenote/one/constants.js';
 import type {
@@ -207,6 +208,47 @@ describe('OneNote rich-content model', () => {
       .reduce((total, stroke) => total + stroke.points.length, 0);
     expect(parsedPoints).toBeLessThanOrEqual(100);
   });
+
+  it('bounds retained rich text across content blocks', () => {
+    const guid = '{33333333-3333-3333-3333-333333333333}';
+    const firstId = id(guid, 1);
+    const secondId = id(guid, 2);
+    const richTextObject = (objectId: ExGuid, text: string) =>
+      object(
+        objectId,
+        JCID.RichTextNode,
+        props(
+          bytesEntry(PROPERTY.RichEditTextUnicode, Buffer.from(text, 'utf16le'))
+        ),
+        guid
+      );
+    const objects = [
+      richTextObject(firstId, 'first'),
+      richTextObject(secondId, 'second'),
+    ];
+    const diagnostics: ParserDiagnostic[] = [];
+    const blocks = parseContentObjects([firstId, secondId], {
+      space: {
+        id: id(guid, 0),
+        roots: new Map(),
+        objects: new Map(
+          objects.map((value) => [exGuidKey(value.id), value] as const)
+        ),
+      },
+      limits: { ...DEFAULT_ONENOTE_PARSER_LIMITS, maxExtractedTextChars: 8 },
+      diagnostics,
+      resources: new Map(),
+    });
+
+    expect(blocks).toHaveLength(1);
+    expect(blocks[0]).toMatchObject({ kind: 'text', text: 'first' });
+    expect(diagnostics).toContainEqual(
+      expect.objectContaining({
+        code: 'CONTENT_PARSE_FAILED',
+        message: expect.stringContaining('Rich-text character count exceeds 8'),
+      })
+    );
+  });
 });
 
 function parseSyntheticLink(href: string): OneNoteTextBlock {