diff --git a/apps/server/src/collaboration/collaboration.util.ts b/apps/server/src/collaboration/collaboration.util.ts
index 50e961ce..6f6d04c4 100644
--- a/apps/server/src/collaboration/collaboration.util.ts
+++ b/apps/server/src/collaboration/collaboration.util.ts
@@ -141,7 +141,57 @@ export function htmlToJson(html: string) {
   }
 }
 
-export function jsonToText(tiptapJson: JSONContent) {
+/**
+ * Deterministic text-serializer overrides for the `format:"text"` page read
+ * (#502). Non-text nodes render to a STABLE placeholder instead of their
+ * (structure-dependent) inner text, so a machine diff of two text reads is
+ * driven only by the page's actual prose — output stability across package
+ * versions IS the contract (pinned by a snapshot test). Returning a string from
+ * a `textSerializer` also stops `generateText` descending into the node, so a
+ * table renders as ONE token rather than its flattened cell text.
+ *
+ * Only nodes with no meaningful flat-text form are overridden; every other node
+ * (paragraph/heading/list/code/blockquote/callout/…) keeps its natural text so
+ * a config written as markdown reads back byte-identical.
+ */
+const TEXT_READ_SERIALIZERS: Record<string, (props: { node: any }) => string> =
+  {
+    // Image atom: no inner text -> a fixed placeholder.
+    image: () => '[image]',
+    // Table: `[table RxC]` where R = row count, C = the first row's cell count
+    // (a table's columns are uniform per the schema). Computed from the PM node,
+    // so it is independent of cell contents.
+    table: ({ node }) => {
+      const rows = node?.childCount ?? 0;
+      const cols = rows > 0 ? (node.child(0)?.childCount ?? 0) : 0;
+      return `[table ${rows}x${cols}]`;
+    },
+  };
+
+/**
+ * Serialize a ProseMirror/TipTap document to plain text.
+ *
+ * Default (no options): the long-standing search-index behavior — bare
+ * concatenated node text with `generateText`'s default `\n\n` block separator.
+ * This feeds the page `textContent` tsvector and MUST NOT change.
+ *
+ * `deterministic:true` (#502 `format:"text"` page read): a flat, machine-diffable
+ * rendering — one line per block (`\n` block separator; `hardBreak` already
+ * serializes to `\n`), inline marks/anchors/autoformat dropped, and non-text
+ * nodes replaced by the stable placeholders above (`[image]`, `[table RxC]`).
+ */
+export function jsonToText(
+  // `any` (like jsonToHtml/jsonToMarkdown) so a loosely-typed DB `page.content`
+  // (JsonValue) can be passed straight through, as the controller does.
+  tiptapJson: any,
+  options?: { deterministic?: boolean },
+) {
+  if (options?.deterministic) {
+    return generateText(tiptapJson, tiptapExtensions, {
+      blockSeparator: '\n',
+      textSerializers: TEXT_READ_SERIALIZERS,
+    });
+  }
   return generateText(tiptapJson, tiptapExtensions);
 }
 
diff --git a/apps/server/src/collaboration/json-to-text-deterministic.spec.ts b/apps/server/src/collaboration/json-to-text-deterministic.spec.ts
new file mode 100644
index 00000000..4a563758
--- /dev/null
+++ b/apps/server/src/collaboration/json-to-text-deterministic.spec.ts
@@ -0,0 +1,116 @@
+import { jsonToText } from './collaboration.util';
+
+// #502 READ contract: `jsonToText(json, { deterministic: true })` — the flat,
+// machine-diffable text rendering behind getPage `format:"text"`. Block-per-line
+// (`\n` separator), inline marks/anchors dropped, hardBreak -> `\n`, and non-text
+// nodes replaced by STABLE placeholders (`[image]`, `[table RxC]`). Output
+// stability across package versions IS the contract, so it is pinned by a
+// snapshot below. The DEFAULT (no options) path is the search-index serializer
+// and MUST be unchanged — asserted separately.
+
+const doc = (...content: any[]) => ({ type: 'doc', content });
+const para = (...content: any[]) => ({ type: 'paragraph', content });
+const text = (t: string, marks?: any[]) =>
+  marks ? { type: 'text', text: t, marks } : { type: 'text', text: t };
+
+describe('jsonToText — default (search index) behavior is unchanged', () => {
+  it('uses the `\\n\\n` block separator and drops non-text nodes to empty', () => {
+    const d = doc(para(text('alpha')), para(text('beta')));
+    expect(jsonToText(d)).toBe('alpha\n\nbeta');
+  });
+
+  it('an image contributes no text in the default (tsvector) mode', () => {
+    const d = doc(para(text('cap')), { type: 'image', attrs: { src: 's' } });
+    // No `[image]` placeholder leaks into the search index.
+    expect(jsonToText(d)).not.toContain('[image]');
+  });
+});
+
+describe('jsonToText — deterministic:true (getPage format:"text")', () => {
+  it('renders one line per block with `\\n` separators, marks dropped', () => {
+    const d = doc(
+      { type: 'heading', attrs: { level: 2 }, content: [text('Title')] },
+      para(
+        text('hello ', [{ type: 'bold' }]),
+        text('world', [{ type: 'italic' }]),
+      ),
+    );
+    expect(jsonToText(d, { deterministic: true })).toBe('Title\nhello world');
+  });
+
+  it('a hardBreak renders as a newline', () => {
+    const d = doc(para(text('a'), { type: 'hardBreak' }, text('b')));
+    expect(jsonToText(d, { deterministic: true })).toBe('a\nb');
+  });
+
+  it('an image node -> the stable `[image]` placeholder', () => {
+    const d = doc(para(text('before')), { type: 'image', attrs: { src: 's' } });
+    expect(jsonToText(d, { deterministic: true })).toBe('before\n[image]');
+  });
+
+  it('a table -> `[table RxC]` (rows x columns) and its cell text is NOT flattened in', () => {
+    const cell = (t: string) => ({
+      type: 'tableCell',
+      content: [para(text(t))],
+    });
+    const row = (...cells: any[]) => ({ type: 'tableRow', content: cells });
+    const table = {
+      type: 'table',
+      content: [
+        row(cell('CELLONE'), cell('CELLTWO'), cell('CELLTHREE')),
+        row(cell('CELLFOUR'), cell('CELLFIVE'), cell('CELLSIX')),
+      ],
+    };
+    const d = doc(para(text('grid:')), table);
+    const out = jsonToText(d, { deterministic: true });
+    expect(out).toBe('grid:\n[table 2x3]');
+    expect(out).not.toContain('CELL'); // cell text is not flattened into the read
+  });
+
+  it('SNAPSHOT: a mixed document renders to a stable, deterministic string', () => {
+    const cell = (t: string) => ({
+      type: 'tableCell',
+      content: [para(text(t))],
+    });
+    const d = doc(
+      { type: 'heading', attrs: { level: 1 }, content: [text('Config')] },
+      para(text('key = ', [{ type: 'bold' }]), text('value')),
+      {
+        type: 'bulletList',
+        content: [
+          { type: 'listItem', content: [para(text('one'))] },
+          { type: 'listItem', content: [para(text('two'))] },
+        ],
+      },
+      { type: 'image', attrs: { src: 's' } },
+      {
+        type: 'table',
+        content: [{ type: 'tableRow', content: [cell('x'), cell('y')] }],
+      },
+    );
+    expect(jsonToText(d, { deterministic: true })).toMatchInlineSnapshot(`
+     "Config
+     key = value
+
+
+     one
+
+     two
+     [image]
+     [table 1x2]"
+    `);
+  });
+
+  it('SCENARIO: a config written as a code block reads back byte-identical (diff empty)', () => {
+    const config =
+      'export TICKET_LIFETIME=$2592000\nservers:\n  - www.internal.host';
+    const d = doc({
+      type: 'codeBlock',
+      attrs: { language: 'yaml' },
+      content: [text(config)],
+    });
+    // The code block is one block; its text (dollars, bare domain, newlines) is
+    // preserved verbatim, so a read-as-text of a stored config diffs empty.
+    expect(jsonToText(d, { deterministic: true })).toBe(config);
+  });
+});
diff --git a/apps/server/src/core/page/dto/create-page.dto.ts b/apps/server/src/core/page/dto/create-page.dto.ts
index 81b15903..7f0757b2 100644
--- a/apps/server/src/core/page/dto/create-page.dto.ts
+++ b/apps/server/src/core/page/dto/create-page.dto.ts
@@ -10,6 +10,12 @@ import { Transform } from 'class-transformer';
 
 export type ContentFormat = 'json' | 'markdown' | 'html';
 
+// READ-only rendering formats for `getPage` (#502). A superset of the writable
+// `ContentFormat` with `text` — a flat, deterministic, machine-diffable text
+// rendering — added. Kept SEPARATE from `ContentFormat` so the write path
+// (createPage/updatePage `parseProsemirrorContent`) can never be handed `text`.
+export type PageReadFormat = ContentFormat | 'text';
+
 export class CreatePageDto {
   @IsOptional()
   @IsString()
diff --git a/apps/server/src/core/page/dto/page.dto.ts b/apps/server/src/core/page/dto/page.dto.ts
index c3b64b23..861587da 100644
--- a/apps/server/src/core/page/dto/page.dto.ts
+++ b/apps/server/src/core/page/dto/page.dto.ts
@@ -8,7 +8,7 @@ import {
 } from 'class-validator';
 import { Transform } from 'class-transformer';
 
-import { ContentFormat } from './create-page.dto';
+import { PageReadFormat } from './create-page.dto';
 import { IsPageIdOrSlugId } from './page-identity.validator';
 
 export class PageIdDto {
@@ -43,8 +43,8 @@ export class PageInfoDto extends PageIdDto {
 
   @IsOptional()
   @Transform(({ value }) => value?.toLowerCase())
-  @IsIn(['json', 'markdown', 'html'])
-  format?: ContentFormat;
+  @IsIn(['json', 'markdown', 'html', 'text'])
+  format?: PageReadFormat;
 }
 
 export class DeletePageDto extends PageIdDto {
diff --git a/apps/server/src/core/page/page.controller.getpage-format.spec.ts b/apps/server/src/core/page/page.controller.getpage-format.spec.ts
new file mode 100644
index 00000000..32e8cd25
--- /dev/null
+++ b/apps/server/src/core/page/page.controller.getpage-format.spec.ts
@@ -0,0 +1,76 @@
+import { NotFoundException } from '@nestjs/common';
+import { PageController } from './page.controller';
+import { jsonToText, jsonToMarkdown } from '../../collaboration/collaboration.util';
+
+// #502 READ: getPage `format:"text"` routes through the deterministic jsonToText
+// path (placeholders for non-text nodes, block-per-line), while `format:"json"`
+// (or none) returns the raw content and `format:"markdown"` still converts. This
+// pins the CONTROLLER wiring with lightweight mocks (no DB needed — the jsonToText
+// output contract itself is pinned in json-to-text-deterministic.spec.ts).
+
+const CONTENT = {
+  type: 'doc',
+  content: [
+    { type: 'heading', attrs: { level: 1 }, content: [{ type: 'text', text: 'Config' }] },
+    {
+      type: 'paragraph',
+      content: [
+        { type: 'text', text: 'key=', marks: [{ type: 'bold' }] },
+        { type: 'text', text: 'value' },
+      ],
+    },
+    { type: 'image', attrs: { src: 's' } },
+  ],
+};
+
+function makeController(page: any): PageController {
+  const pageRepo = { findById: jest.fn().mockResolvedValue(page) } as any;
+  const pageAccessService = {
+    validateCanViewWithPermissions: jest
+      .fn()
+      .mockResolvedValue({ canEdit: true, hasRestriction: false }),
+  } as any;
+  // Only pageRepo + pageAccessService are exercised by getPage; the rest are
+  // never touched on this path, so undefined placeholders are fine.
+  return new PageController(
+    undefined as any, // pageService
+    pageRepo,
+    undefined as any, // pageHistoryService
+    undefined as any, // spaceAbility
+    pageAccessService,
+    undefined as any, // backlinkService
+    undefined as any, // labelService
+    undefined as any, // auditService
+  );
+}
+
+const user = { id: 'u1' } as any;
+
+describe('PageController.getPage — format:"text" (#502)', () => {
+  it('returns deterministic flat text with placeholders for non-text nodes', async () => {
+    const controller = makeController({ id: 'p1', content: CONTENT });
+    const res: any = await controller.getPage({ pageId: 'p1', format: 'text' } as any, user);
+    expect(res.content).toBe(jsonToText(CONTENT, { deterministic: true }));
+    expect(res.content).toBe('Config\nkey=value\n[image]');
+    expect(res.permissions).toEqual({ canEdit: true, hasRestriction: false });
+  });
+
+  it('markdown format still converts to markdown (unchanged)', async () => {
+    const controller = makeController({ id: 'p1', content: CONTENT });
+    const res: any = await controller.getPage({ pageId: 'p1', format: 'markdown' } as any, user);
+    expect(res.content).toBe(jsonToMarkdown(CONTENT));
+  });
+
+  it('json / no format returns the raw ProseMirror content object', async () => {
+    const controller = makeController({ id: 'p1', content: CONTENT });
+    const res: any = await controller.getPage({ pageId: 'p1' } as any, user);
+    expect(res.content).toEqual(CONTENT); // untouched object, not a string
+  });
+
+  it('missing page -> NotFoundException', async () => {
+    const controller = makeController(null);
+    await expect(
+      controller.getPage({ pageId: 'nope', format: 'text' } as any, user),
+    ).rejects.toBeInstanceOf(NotFoundException);
+  });
+});
diff --git a/apps/server/src/core/page/page.controller.ts b/apps/server/src/core/page/page.controller.ts
index 6355b1d3..481177ce 100644
--- a/apps/server/src/core/page/page.controller.ts
+++ b/apps/server/src/core/page/page.controller.ts
@@ -49,6 +49,7 @@ import { AddLabelsDto, RemoveLabelDto } from '../label/dto/label.dto';
 import {
   jsonToHtml,
   jsonToMarkdown,
+  jsonToText,
 } from '../../collaboration/collaboration.util';
 import { AuditEvent, AuditResource } from '../../common/events/audit-events';
 import {
@@ -93,10 +94,16 @@ export class PageController {
     const permissions = { canEdit, hasRestriction };
 
     if (dto.format && dto.format !== 'json' && page.content) {
-      const contentOutput =
-        dto.format === 'markdown'
-          ? jsonToMarkdown(page.content)
-          : jsonToHtml(page.content);
+      let contentOutput: string;
+      if (dto.format === 'markdown') {
+        contentOutput = jsonToMarkdown(page.content);
+      } else if (dto.format === 'text') {
+        // #502: flat, deterministic, machine-diffable text (block-per-line,
+        // inline marks/anchors dropped, non-text nodes -> stable placeholders).
+        contentOutput = jsonToText(page.content, { deterministic: true });
+      } else {
+        contentOutput = jsonToHtml(page.content);
+      }
       return {
         ...page,
         content: contentOutput,
diff --git a/apps/server/src/integrations/import/import.controller.ts b/apps/server/src/integrations/import/import.controller.ts
index c47e87ea..d3121d2b 100644
--- a/apps/server/src/integrations/import/import.controller.ts
+++ b/apps/server/src/integrations/import/import.controller.ts
@@ -85,6 +85,14 @@ export class ImportController {
       throw new BadRequestException('spaceId is required');
     }
 
+    // #502: optional multipart field. Only the MCP agent `createPage` path sends
+    // `disableMarkdownExtensions=true` (its body is agent-authored plain prose /
+    // config, so a `$…$` span must stay literal and a bare `www.host` must not
+    // autolink). A HUMAN file upload omits the field, so it stays false and math
+    // + autolink remain ON for human imports. Settable ONLY via this API param.
+    const disableMarkdownExtensions =
+      file.fields?.disableMarkdownExtensions?.value === 'true';
+
     const ability = await this.spaceAbility.createForUser(user, spaceId);
     if (ability.cannot(SpaceCaslAction.Edit, SpaceCaslSubject.Page)) {
       throw new ForbiddenException();
@@ -95,6 +103,7 @@ export class ImportController {
       user.id,
       spaceId,
       workspace.id,
+      disableMarkdownExtensions,
     );
 
     const ext = path.extname(file.filename).toLowerCase();
diff --git a/apps/server/src/integrations/import/services/import.service.processMarkdown.spec.ts b/apps/server/src/integrations/import/services/import.service.processMarkdown.spec.ts
new file mode 100644
index 00000000..9a0bd646
--- /dev/null
+++ b/apps/server/src/integrations/import/services/import.service.processMarkdown.spec.ts
@@ -0,0 +1,67 @@
+// Importing ImportService transitively loads import-formatter.ts, which imports
+// the ESM-only @sindresorhus/slugify (not in jest's transform allowlist). It is
+// irrelevant to this path, so mock it to keep the module graph loadable (mirrors
+// the sibling import.service specs).
+jest.mock('@sindresorhus/slugify', () => ({
+  __esModule: true,
+  default: (input: string) => String(input),
+}));
+
+import { ImportService } from './import.service';
+
+// #502 BLOCKER 1: the server markdown import path (`/pages/import`) now accepts an
+// optional `disableMarkdownExtensions` flag threaded into `processMarkdown`.
+//   - MCP agent `createPage` sends it TRUE  -> extensions OFF (a `$…$` config span
+//     stays literal, a schemeless `www.host` is not autolinked).
+//   - a HUMAN file upload omits it (default FALSE) -> extensions ON, so a real
+//     `$x^2$` still becomes a formula (human imports unaffected).
+// `processMarkdown` only uses the imported converter (no injected deps on this
+// path), so the service is constructed with null deps for this focused unit test.
+
+function makeService(): ImportService {
+  return new ImportService(null as any, null as any, null as any, null as any);
+}
+
+function findAll(node: any, type: string, acc: any[] = []): any[] {
+  if (!node || typeof node !== 'object') return acc;
+  if (node.type === type) acc.push(node);
+  if (Array.isArray(node.content)) for (const c of node.content) findAll(c, type, acc);
+  return acc;
+}
+function hasLink(node: any): boolean {
+  return findAll(node, 'text').some((t: any) =>
+    t.marks?.some((m: any) => m.type === 'link'),
+  );
+}
+
+describe('ImportService.processMarkdown — #502 disableMarkdownExtensions', () => {
+  it('disableMarkdownExtensions=true (MCP createPage): `$…$` stays literal, no math', async () => {
+    const svc = makeService();
+    const doc = await svc.processMarkdown('export A=$FOO and B=$BAR done', true);
+    expect(findAll(doc, 'mathInline')).toHaveLength(0);
+  });
+
+  it('disableMarkdownExtensions=true: a schemeless www is NOT autolinked', async () => {
+    const svc = makeService();
+    const doc = await svc.processMarkdown('see www.example.com here', true);
+    expect(hasLink(doc)).toBe(false);
+  });
+
+  it('disableMarkdownExtensions=true: an explicit https:// STILL links', async () => {
+    const svc = makeService();
+    const doc = await svc.processMarkdown('see https://example.com here', true);
+    expect(hasLink(doc)).toBe(true);
+  });
+
+  it('DEFAULT (human upload): a real `$x^2$` DOES become a math node', async () => {
+    const svc = makeService();
+    const doc = await svc.processMarkdown('$x^2$');
+    expect(findAll(doc, 'mathInline')).toHaveLength(1);
+  });
+
+  it('DEFAULT (human upload): a schemeless www IS autolinked', async () => {
+    const svc = makeService();
+    const doc = await svc.processMarkdown('see www.example.com here');
+    expect(hasLink(doc)).toBe(true);
+  });
+});
diff --git a/apps/server/src/integrations/import/services/import.service.ts b/apps/server/src/integrations/import/services/import.service.ts
index 7c480ef2..cd4fc1c3 100644
--- a/apps/server/src/integrations/import/services/import.service.ts
+++ b/apps/server/src/integrations/import/services/import.service.ts
@@ -52,6 +52,12 @@ export class ImportService {
     userId: string,
     spaceId: string,
     workspaceId: string,
+    // #502: when true, the markdown importer runs with the two layered
+    // extensions OFF (a `$…$` span stays literal text; a schemeless `www.host` is
+    // NOT autolinked). ONLY the MCP agent `createPage` path sets this; a HUMAN
+    // file upload never passes it, so it defaults false and math/autolink stay ON
+    // for human imports (their `$x^2$` still becomes a formula).
+    disableMarkdownExtensions = false,
   ) {
     const file = await filePromise;
     const fileBuffer = await file.toBuffer();
@@ -66,7 +72,10 @@ export class ImportService {
 
     try {
       if (fileExtension.endsWith('.md')) {
-        prosemirrorState = await this.processMarkdown(fileContent);
+        prosemirrorState = await this.processMarkdown(
+          fileContent,
+          disableMarkdownExtensions,
+        );
       } else if (fileExtension.endsWith('.html')) {
         prosemirrorState = await this.processHTML(fileContent);
       }
@@ -138,7 +147,12 @@ export class ImportService {
     return createdPage;
   }
 
-  async processMarkdown(markdownInput: string): Promise<any> {
+  async processMarkdown(
+    markdownInput: string,
+    // #502: forwarded to the importer. DEFAULT false keeps math + fuzzy autolink
+    // ON (human uploads unaffected); the MCP agent `createPage` path passes true.
+    disableMarkdownExtensions = false,
+  ): Promise<any> {
     // Canonical markdown -> ProseMirror JSON directly via
     // `@docmost/prosemirror-markdown` (issue #345) — no HTML intermediate and no
     // second editor-ext markdown layer. Foreign markdown surfaces the strict
@@ -147,7 +161,12 @@ export class ImportService {
     // The HTML-cleanup pass (`normalizeImportHtml`) is intentionally skipped here:
     // it targets foreign *HTML* (Notion/XWiki), which only ever arrives on the
     // `.html` path (`processHTML`), never as canonical markdown.
-    return markdownToProseMirror(normalizeForeignMarkdown(markdownInput));
+    return markdownToProseMirror(
+      normalizeForeignMarkdown(markdownInput),
+      disableMarkdownExtensions
+        ? { parseMath: false, fuzzyLinkify: false }
+        : undefined,
+    );
   }
 
   async processHTML(htmlInput: string): Promise<any> {
diff --git a/packages/mcp/README.md b/packages/mcp/README.md
index e6c93341..d60409a4 100644
--- a/packages/mcp/README.md
+++ b/packages/mcp/README.md
@@ -118,7 +118,10 @@ All 41 tools, grouped by what you'd reach for them.
 - **`getPage`** — A page's content as clean **Markdown** (canonical for text; drops only
   block ids, resolved-comment anchors, and a fixed no-Markdown-representation attr set —
   table spans/colwidth/background, indent, `callout.icon`, `orderedList.type`, and link
-  `internal`/`target`/`rel`/`class`; use `getPageJson` when you need those).
+  `internal`/`target`/`rel`/`class`; use `getPageJson` when you need those). Pass
+  `format:"text"` for a flat, deterministic plain-text rendering (one line per block,
+  marks dropped, stable `[image]`/`[table RxC]` placeholders) to machine-diff what you
+  wrote against what was stored.
 - **`getPageJson`** — A page's **lossless ProseMirror/TipTap JSON**, including every
   block's `attrs.id` and the `slugId` used in URLs. This is what the per-block editing
   tools consume.
diff --git a/packages/mcp/README.ru.md b/packages/mcp/README.ru.md
index 3b3de41d..574839d6 100644
--- a/packages/mcp/README.ru.md
+++ b/packages/mcp/README.ru.md
@@ -123,7 +123,10 @@ Docmost-MCP не сочетают:
   лишь id блоков, якоря разрешённых комментариев и фиксированный набор атрибутов без
   markdown-представления — спаны/colwidth/фон ячеек таблиц, отступы (indent),
   `callout.icon`, `orderedList.type` и `internal`/`target`/`rel`/`class` у ссылок;
-  используйте `getPageJson`, когда они нужны).
+  используйте `getPageJson`, когда они нужны). Передайте `format:"text"` для плоского
+  детерминированного plain-text рендера (одна строка на блок, маркировка убрана,
+  стабильные плейсхолдеры `[image]`/`[table RxC]`) — чтобы machine-diff'ом сверить то,
+  что вы записали, с тем, что сохранилось.
 - **`getPageJson`** — **Lossless ProseMirror/TipTap JSON** страницы, включая `attrs.id`
   каждого блока и `slugId`, используемый в URL. Именно его потребляют инструменты
   поблочного редактирования.
diff --git a/packages/mcp/src/client/context.ts b/packages/mcp/src/client/context.ts
index 8b15a1ac..95c6de85 100644
--- a/packages/mcp/src/client/context.ts
+++ b/packages/mcp/src/client/context.ts
@@ -911,10 +911,20 @@ export abstract class DocmostClientContext {
   }
 
 
-  /** Raw page info including the ProseMirror JSON content and slugId. */
-  async getPageRaw(pageId: string) {
+  /**
+   * Raw page info including the ProseMirror JSON content and slugId.
+   *
+   * With `format:"text"` (#502) the server instead renders `content` as a flat,
+   * deterministic text string (its `jsonToText` path — the SAME serializer that
+   * feeds search), so the MCP text read reuses the server's ONE serializer
+   * rather than shipping a second one. Every other caller omits `format` and
+   * gets the JSON content unchanged.
+   */
+  async getPageRaw(pageId: string, format?: "text") {
     await this.ensureAuthenticated();
-    const response = await this.client.post("/pages/info", { pageId });
+    const body: Record<string, unknown> = { pageId };
+    if (format) body.format = format;
+    const response = await this.client.post("/pages/info", body);
     return response.data?.data ?? response.data;
   }
 
diff --git a/packages/mcp/src/client/pages.ts b/packages/mcp/src/client/pages.ts
index 8d69603b..d3520040 100644
--- a/packages/mcp/src/client/pages.ts
+++ b/packages/mcp/src/client/pages.ts
@@ -93,6 +93,13 @@ export function PagesMixin<TBase extends GConstructor<DocmostClientContext>>(Bas
     const buildForm = () => {
       const form = new FormData();
       form.append("spaceId", spaceId);
+      // #502: this is an AGENT-authored body (plain prose / config), so tell the
+      // server import path to run the markdown importer with the two layered
+      // extensions OFF — a `$…$` span stays literal text (real math via
+      // `update_page_json`) and a schemeless `www.host`/email is not autolinked
+      // (an explicit `https://…` still links). A human file upload never sends
+      // this field, so human imports keep math + autolink ON.
+      form.append("disableMarkdownExtensions", "true");
       form.append("file", fileContent, {
         filename: `${title || "import"}.md`,
         contentType: "text/markdown",
diff --git a/packages/mcp/src/client/read.ts b/packages/mcp/src/client/read.ts
index 85fb9fa6..9d3cfb20 100644
--- a/packages/mcp/src/client/read.ts
+++ b/packages/mcp/src/client/read.ts
@@ -72,7 +72,7 @@ export interface IReadMixin {
   getTree(spaceId: string, rootPageId?: string, maxDepth?: number): any;
   getPageContext(pageId: string): any;
   listSidebarPages(spaceId: string, pageId?: string): any;
-  getPage(pageId: string): any;
+  getPage(pageId: string, format?: "markdown" | "text"): any;
   getPageJson(pageId: string): any;
   getOutline(pageId: string): any;
   getNode(pageId: string, nodeId: string, format?: "markdown" | "json"): any;
@@ -440,8 +440,34 @@ export function ReadMixin<TBase extends GConstructor<DocmostClientContext>>(Base
     return convertProseMirrorToMarkdown(content, options);
   }
 
-  async getPage(pageId: string) {
+  async getPage(pageId: string, format: "markdown" | "text" = "markdown") {
     await this.ensureAuthenticated();
+
+    // #502 `format:"text"`: a flat, deterministic, machine-diffable rendering
+    // (block-per-line, inline marks/comment anchors dropped, non-text nodes ->
+    // stable placeholders like `[image]` / `[table RxC]`). The server produces
+    // it via its `jsonToText` path (the SAME serializer that feeds search), so
+    // there is no second serializer here — we just request it and pass the
+    // string through. Distinct from the markdown default: no PM->markdown walk,
+    // no markdown conversion cache, and no `{{SUBPAGES}}` substitution (the text
+    // renderer emits no such placeholder). Use it to diff a page you wrote as a
+    // config/prose against what was stored.
+    if (format === "text") {
+      const textData = await this.getPageRaw(pageId, "text");
+      let subpages: any[] = [];
+      try {
+        subpages = await this.listSidebarPages(textData.spaceId, textData.id);
+      } catch (e: any) {
+        console.warn("Failed to fetch subpages:", e);
+      }
+      const textContent =
+        typeof textData.content === "string" ? textData.content : "";
+      return {
+        data: filterPage(textData, textContent, subpages),
+        success: true,
+      };
+    }
+
     const resultData = await this.getPageRaw(pageId);
 
     // Agent read: hide resolved-comment anchors so the agent sees only active
diff --git a/packages/mcp/src/lib/collaboration.ts b/packages/mcp/src/lib/collaboration.ts
index 0de4e497..379c99dc 100644
--- a/packages/mcp/src/lib/collaboration.ts
+++ b/packages/mcp/src/lib/collaboration.ts
@@ -14,6 +14,7 @@ import {
   markdownToProseMirror,
   normalizeAgentMarkdown,
 } from "@docmost/prosemirror-markdown";
+import type { MarkdownImportOptions } from "@docmost/prosemirror-markdown";
 import { docmostExtensions, docmostSchema } from "./docmost-schema.js";
 import { withPageLock } from "./page-lock.js";
 import type { PageId } from "./page-id.js";
@@ -111,16 +112,31 @@ global.WebSocket = WebSocket;
  * horizontalRule the serializer emitted, and stripping it would silently drop the
  * page's leading content (#493 review). The front-matter strip stays on the
  * server FILE-import boundary only (`normalizeForeignMarkdown`).
+ *
+ * #502 IMPORTANT — the two layered markdown extensions (`$…$` math, schemeless
+ * fuzzy autolink) are NOT decided here; they are the CALLER's choice via
+ * `options`, because the two callers of this wrapper need OPPOSITE behavior:
+ *   - AGENT-authored plain markdown (`updatePageMarkdown`) → both OFF, so a
+ *     `$…$` config span stays literal and a bare `www.host` is not autolinked
+ *     (real math is authored via `update_page_json`).
+ *   - FULL-FILE round-trip import (`import_page_markdown`, #328 lossless) →
+ *     DEFAULTS (both ON), because the exporter serializes a math node as readable
+ *     `$x^2$`; re-importing with math OFF would degrade it to literal text and
+ *     BREAK the lossless export→import pair.
+ * So `options` DEFAULTS to `undefined` → the package importer's defaults (ON),
+ * which is the safe round-trip behavior; the agent-write caller opts OUT
+ * explicitly. (The fragment path `importMarkdownFragment` opts out on its own.)
  */
 export async function markdownToProseMirrorCanonical(
   markdownContent: string,
+  options?: MarkdownImportOptions,
 ): Promise<any> {
   // #419: normalize + merge glyph-forked footnote definitions BEFORE
   // canonicalizing, so the canonicalizer re-hangs references and drops the
   // now-orphaned duplicate definitions.
   return canonicalizeFootnotes(
     normalizeAndMergeFootnotes(
-      await markdownToProseMirror(normalizeAgentMarkdown(markdownContent)),
+      await markdownToProseMirror(normalizeAgentMarkdown(markdownContent), options),
     ),
   );
 }
@@ -358,7 +374,17 @@ export async function updatePageContentRealtime(
 ): Promise<MutationResult> {
   // PAGE write: canonicalize footnotes (markdown import builds the bottom list in
   // definition order; numbering is reference-ordered).
-  const tiptapJson = await markdownToProseMirrorCanonical(markdownContent);
+  //
+  // #502: this is the AGENT-authored `updatePageMarkdown` body — plain prose /
+  // config — so the two layered markdown extensions are turned OFF: a `$…$` span
+  // stays literal text (real math via `update_page_json`) and a SCHEMELESS
+  // `www.host`/email is not autolinked (an explicit `https://…` still links).
+  // Contrast `import_page_markdown`, which keeps DEFAULTS for the #328 lossless
+  // round-trip.
+  const tiptapJson = await markdownToProseMirrorCanonical(markdownContent, {
+    parseMath: false,
+    fuzzyLinkify: false,
+  });
   return await mutatePageContent(
     pageId,
     collabToken,
diff --git a/packages/mcp/src/lib/markdown-fragment.ts b/packages/mcp/src/lib/markdown-fragment.ts
index 79796212..c24862e8 100644
--- a/packages/mcp/src/lib/markdown-fragment.ts
+++ b/packages/mcp/src/lib/markdown-fragment.ts
@@ -135,7 +135,17 @@ export interface MarkdownFragment {
 export async function importMarkdownFragment(
   markdown: string,
 ): Promise<MarkdownFragment> {
-  const doc = await markdownToProseMirror(markdown);
+  // #502: the fragment path is an MCP agent WRITE (patch_node/insert_node
+  // markdown), so it uses the SAME extensions-OFF importer options as the
+  // full-page write (markdownToProseMirrorCanonical): a `$…$` span stays literal
+  // and a schemeless domain/email is not autolinked. This keeps a block written
+  // via markdown canonically identical to the same content in a full-page write
+  // (no "second canon"). Explicit `https://…` links and block structure are
+  // unaffected.
+  const doc = await markdownToProseMirror(markdown, {
+    parseMath: false,
+    fuzzyLinkify: false,
+  });
   const content: any[] = Array.isArray(doc?.content) ? doc.content : [];
 
   const blocks: any[] = [];
diff --git a/packages/mcp/src/tool-specs.ts b/packages/mcp/src/tool-specs.ts
index f3f0a2fe..c94eba12 100644
--- a/packages/mcp/src/tool-specs.ts
+++ b/packages/mcp/src/tool-specs.ts
@@ -469,7 +469,11 @@ export const SHARED_TOOL_SPECS = {
       '(markdown). The fragment may be SEVERAL blocks (a "1 → N" splice: rewrite a ' +
       'whole section in one call) — the first block inherits this block id, the ' +
       'rest get fresh ids. `^[...]` footnotes are supported (their definitions ' +
-      "merge into the page's footnote list). REJECTED when the target is a table " +
+      "merge into the page's footnote list). Markdown is taken LITERALLY — " +
+      '`$...$`/`$$...$$` are NOT parsed as math and schemeless `www.host` / bare ' +
+      'emails are NOT auto-linked (an explicit `https://` URL still links); for a ' +
+      'real formula pass a `mathInline`/`mathBlock` ProseMirror node via `node` ' +
+      '(or updatePageJson). REJECTED when the target is a table ' +
       'cell with attributes markdown cannot represent (merged/colored/fixed-width) ' +
       '— use the table tools or `node`. ' +
       '`node` (for precise attr/mark work): a raw ProseMirror node, e.g. a ' +
@@ -535,6 +539,10 @@ export const SHARED_TOOL_SPECS = {
       'Provide EXACTLY ONE of `markdown` or `node`. ' +
       '`markdown` (RECOMMENDED): a canonical markdown fragment — may be SEVERAL ' +
       'blocks, inserted in order at the anchor; `^[...]` footnotes supported. ' +
+      'Markdown is taken LITERALLY — `$...$`/`$$...$$` are NOT parsed as math and ' +
+      'schemeless `www.host` / bare emails are NOT auto-linked (an explicit ' +
+      '`https://` URL still links); for a real formula pass a ' +
+      '`mathInline`/`mathBlock` ProseMirror node via `node` (or updatePageJson). ' +
       '`node` (for precise attr/mark work OR table structure): a raw ProseMirror ' +
       'node. Table structure is JSON-only (not expressible in markdown): to add a ' +
       'tableRow, pass a tableRow node with position before/after and anchor INSIDE ' +
@@ -913,28 +921,46 @@ export const SHARED_TOOL_SPECS = {
     inAppKey: 'getPage',
     writeClass: 'readOnly',
     description:
-      'Fetch a single page as Markdown by its id. Returns the page title and ' +
-      'its Markdown content. The converter is canonical (round-trips text and ' +
-      'block structure), so this is sufficient for text edits; use the ' +
-      'page-JSON read tool only when you need what Markdown cannot carry. The ' +
-      'Markdown drops exactly: (1) block ids (not visible in Markdown); ' +
-      '(2) resolved-comment anchors (hidden here; only active <span ' +
-      'data-comment-id> anchors remain); (3) a fixed set of attributes with no ' +
-      'Markdown representation — table-cell colspan/rowspan/colwidth/' +
-      'backgroundColor/backgroundColorName, heading/paragraph indent, ' +
-      'callout.icon, orderedList.type, and link internal/target/rel/class. ' +
-      'Inline <span data-comment-id> tags in the markdown are comment highlight ' +
-      'anchors — treat them as markup, not page text.',
+      'Fetch a single page by its id. Returns the page title and its content. ' +
+      'format:"markdown" (DEFAULT) returns canonical Markdown (round-trips text ' +
+      'and block structure), sufficient for text edits; use the page-JSON read ' +
+      'tool only when you need what Markdown cannot carry. The Markdown drops ' +
+      'exactly: (1) block ids (not visible in Markdown); (2) resolved-comment ' +
+      'anchors (hidden here; only active <span data-comment-id> anchors remain); ' +
+      '(3) a fixed set of attributes with no Markdown representation — table-cell ' +
+      'colspan/rowspan/colwidth/backgroundColor/backgroundColorName, ' +
+      'heading/paragraph indent, callout.icon, orderedList.type, and link ' +
+      'internal/target/rel/class. Inline <span data-comment-id> tags in the ' +
+      'markdown are comment highlight anchors — treat them as markup, not page ' +
+      'text. format:"text" returns a FLAT, DETERMINISTIC plain-text rendering ' +
+      'for machine diffing: one line per block, ALL inline marks/formatting and ' +
+      'comment anchors dropped, a hardBreak is a newline, and non-text nodes ' +
+      'become STABLE placeholders — an image is "[image]" and a table is ' +
+      '"[table RxC]" (R rows x C columns). This output is stable across versions ' +
+      '(pinned by a snapshot test); use it to diff a config/prose you wrote ' +
+      'against what was stored (an empty diff means it was stored verbatim).',
     tier: 'core',
-    catalogLine: 'getPage — fetch a page as Markdown by its id.',
+    catalogLine:
+      'getPage — fetch a page by its id (format:"markdown" default, or "text" for a flat machine-diffable read).',
     // Reconciled: MCP's stricter .min(1) kept; in-app's more-informative
     // "(or slugId)" describe kept.
     buildShape: (z) => ({
       pageId: z.string().min(1).describe('The id (or slugId) of the page.'),
+      format: z
+        .enum(['markdown', 'text'])
+        .optional()
+        .describe(
+          'Output format: "markdown" (default, canonical round-trippable) or ' +
+            '"text" (flat deterministic plain text for machine diffing).',
+        ),
     }),
     // MCP wraps the raw `{ data, success }` as JSON. The in-app host instead
     // projects a token-efficient `{ title, markdown }` (its long-standing shape).
-    execute: (client, { pageId }) => client.getPage(pageId as string),
+    execute: (client, { pageId, format }) =>
+      client.getPage(
+        pageId as string,
+        (format as 'markdown' | 'text' | undefined) ?? 'markdown',
+      ),
     inAppExecute: async (client, { pageId }) => {
       // getPage(pageId) -> { data: filterPage(page, markdown), success }.
       const result = (await client.getPage(pageId as string)) as {
@@ -1077,8 +1103,12 @@ export const SHARED_TOOL_SPECS = {
     description:
       'Create a new page with a Markdown body in a space, optionally under a ' +
       'parent page (omit parentPageId to create at the space root). Returns ' +
-      'the new page id and title. Reversible: a page can be moved to trash ' +
-      'later.',
+      'the new page id and title. Body text is taken LITERALLY — ' +
+      '`$...$`/`$$...$$` are NOT parsed into a math formula and schemeless ' +
+      '`www.host` / bare emails are NOT auto-linked (an explicit `https://` URL ' +
+      'still links); for a real formula use updatePageJson with ' +
+      '`mathInline`/`mathBlock` nodes instead. Reversible: a page can be moved ' +
+      'to trash later.',
     tier: 'deferred',
     catalogLine: 'createPage — create a new page with a Markdown body in a space.',
     // Reconciled schema DRIFT: the MCP copy pinned `content` to .min(1) while
@@ -1337,7 +1367,11 @@ export const SHARED_TOOL_SPECS = {
       'title). The whole body is re-imported from the markdown (block ids ' +
       'regenerate — for surgical or id-preserving edits use the find/replace, ' +
       'node-patch or page-JSON tools instead). Docmost-flavoured markdown is ' +
-      'parsed, including `^[...]` inline footnotes. Reversible: the previous ' +
+      'parsed, including `^[...]` inline footnotes. Text is taken LITERALLY — ' +
+      '`$...$`/`$$...$$` are NOT parsed into a math formula and schemeless ' +
+      '`www.host` / bare emails are NOT auto-linked (an explicit `https://` URL ' +
+      'still links); for a real formula use updatePageJson with ' +
+      '`mathInline`/`mathBlock` nodes instead. Reversible: the previous ' +
       'version is kept in page history.',
     tier: 'deferred',
     catalogLine:
diff --git a/packages/mcp/test/mock/createpage-import-flag.test.mjs b/packages/mcp/test/mock/createpage-import-flag.test.mjs
new file mode 100644
index 00000000..c1067849
--- /dev/null
+++ b/packages/mcp/test/mock/createpage-import-flag.test.mjs
@@ -0,0 +1,83 @@
+// #502 BLOCKER 1 (client half): the MCP `createPage` tool builds its body as an
+// AGENT-authored markdown file and POSTs it to the server `/pages/import`
+// endpoint. It must send the `disableMarkdownExtensions=true` multipart field so
+// the SERVER importer runs with math + fuzzy-autolink OFF (a human file upload
+// omits the field and keeps them ON). This mock http server captures the raw
+// multipart body and asserts the field is present.
+import { test, after } from "node:test";
+import assert from "node:assert/strict";
+import http from "node:http";
+import { DocmostClient } from "../../build/client.js";
+
+function sendJson(res, status, obj, extra = {}) {
+  res.writeHead(status, { "Content-Type": "application/json", ...extra });
+  res.end(JSON.stringify(obj));
+}
+function readRaw(req) {
+  return new Promise((resolve) => {
+    const chunks = [];
+    req.on("data", (c) => chunks.push(c));
+    req.on("end", () => resolve(Buffer.concat(chunks).toString("utf-8")));
+  });
+}
+
+const openServers = [];
+after(async () => {
+  await Promise.all(openServers.map((s) => new Promise((r) => s.close(r))));
+});
+
+const NEW_ID = "00000000-0000-4000-8000-000000000042";
+const SPACE = "00000000-0000-4000-8000-0000000000aa";
+
+function spawn(state) {
+  return new Promise((resolve) => {
+    const server = http.createServer(async (req, res) => {
+      const raw = await readRaw(req);
+      if (req.url === "/api/auth/login") {
+        return sendJson(res, 200, { success: true }, { "Set-Cookie": "authToken=t; Path=/; HttpOnly" });
+      }
+      if (req.url === "/api/pages/import") {
+        state.importBody = raw; // the raw multipart payload
+        return sendJson(res, 200, { data: { id: NEW_ID } });
+      }
+      if (req.url === "/api/pages/update") {
+        return sendJson(res, 200, { data: { id: NEW_ID } });
+      }
+      if (req.url === "/api/pages/info") {
+        return sendJson(res, 200, {
+          data: {
+            id: NEW_ID,
+            slugId: "slugnew1234",
+            title: "T",
+            spaceId: SPACE,
+            updatedAt: "2026-01-01T00:00:00Z",
+            content: { type: "doc", content: [{ type: "paragraph", content: [{ type: "text", text: "x" }] }] },
+          },
+        });
+      }
+      if (req.url === "/api/pages/sidebar-pages") {
+        return sendJson(res, 200, { data: { items: [], meta: { hasNextPage: false, nextCursor: null } } });
+      }
+      return sendJson(res, 404, { message: "not found" });
+    });
+    server.listen(0, "127.0.0.1", () => {
+      openServers.push(server);
+      resolve(`http://127.0.0.1:${server.address().port}/api`);
+    });
+  });
+}
+
+test("createPage sends disableMarkdownExtensions=true in the /pages/import multipart", async () => {
+  const state = {};
+  const baseURL = await spawn(state);
+  const client = new DocmostClient(baseURL, "e@x.com", "pw");
+
+  await client.createPage("My Config", "ticket $x=1$ at www.host.com", SPACE);
+
+  assert.ok(state.importBody, "the import endpoint received a body");
+  // The multipart payload carries the field name and its "true" value.
+  assert.match(state.importBody, /name="disableMarkdownExtensions"/);
+  assert.match(state.importBody, /name="disableMarkdownExtensions"[\s\S]*?\r?\n\r?\ntrue\r?\n/);
+  // The agent body itself is still sent as the file part.
+  assert.match(state.importBody, /ticket \$x=1\$ at www\.host\.com/);
+});
diff --git a/packages/mcp/test/mock/getpage-text-format.test.mjs b/packages/mcp/test/mock/getpage-text-format.test.mjs
new file mode 100644
index 00000000..958ffefe
--- /dev/null
+++ b/packages/mcp/test/mock/getpage-text-format.test.mjs
@@ -0,0 +1,116 @@
+// #502 READ: the getPage tool gains a `format:"text"` mode. It requests the
+// server's flat, deterministic text rendering (the server's jsonToText path — the
+// SAME serializer that feeds search), passing it through unchanged. This mock
+// stands up a local http server (same harness style as getpage-conversion-cache)
+// and asserts end-to-end that:
+//   - format:"text" sends `format:"text"` in the /pages/info body and returns the
+//     server's text string verbatim (no client-side markdown conversion);
+//   - the DEFAULT (no format) still returns markdown-converted content;
+//   - the text read resolves page + subpages like the markdown read.
+import { test, after } from "node:test";
+import assert from "node:assert/strict";
+import http from "node:http";
+import { DocmostClient } from "../../build/client.js";
+
+function readBody(req) {
+  return new Promise((resolve) => {
+    let raw = "";
+    req.on("data", (c) => (raw += c));
+    req.on("end", () => resolve(raw));
+  });
+}
+function sendJson(res, status, obj, extra = {}) {
+  res.writeHead(status, { "Content-Type": "application/json", ...extra });
+  res.end(JSON.stringify(obj));
+}
+
+const openServers = [];
+after(async () => {
+  await Promise.all(openServers.map((s) => new Promise((r) => s.close(r))));
+});
+
+const PAGE_UUID = "00000000-0000-4000-8000-000000000010";
+const SPACE_UUID = "00000000-0000-4000-8000-0000000000aa";
+const CHILD_UUID = "00000000-0000-4000-8000-0000000000bb";
+
+// The deterministic text the SERVER's jsonToText would produce for this page.
+const SERVER_TEXT = "Title line\nsecond block\n[image]\n[table 2x3]";
+
+function makeDoc(text) {
+  return { type: "doc", content: [{ type: "paragraph", content: [{ type: "text", text }] }] };
+}
+
+function spawn(state) {
+  return new Promise((resolve) => {
+    const server = http.createServer(async (req, res) => {
+      const body = await readBody(req);
+      if (req.url === "/api/auth/login") {
+        return sendJson(res, 200, { success: true }, { "Set-Cookie": "authToken=t; Path=/; HttpOnly" });
+      }
+      if (req.url === "/api/pages/info") {
+        const parsed = body ? JSON.parse(body) : {};
+        state.lastInfoBody = parsed;
+        // Emulate the server: when format:"text" is requested, `content` is the
+        // flat text string; otherwise it is the raw ProseMirror JSON.
+        const content = parsed.format === "text" ? SERVER_TEXT : makeDoc("Title line");
+        return sendJson(res, 200, {
+          success: true,
+          data: {
+            id: PAGE_UUID,
+            slugId: "slug123456",
+            title: "Text Page",
+            parentPageId: null,
+            spaceId: SPACE_UUID,
+            updatedAt: "2026-01-01T00:00:00Z",
+            content,
+          },
+        });
+      }
+      if (req.url === "/api/pages/sidebar-pages") {
+        return sendJson(res, 200, {
+          success: true,
+          data: {
+            items: [{ id: CHILD_UUID, title: "Child", hasChildren: false }],
+            meta: { hasNextPage: false, nextCursor: null },
+          },
+        });
+      }
+      return sendJson(res, 404, { message: "not found" });
+    });
+    server.listen(0, "127.0.0.1", () => {
+      openServers.push(server);
+      resolve(`http://127.0.0.1:${server.address().port}/api`);
+    });
+  });
+}
+
+function makeClient(baseURL) {
+  return new DocmostClient({ apiUrl: baseURL, getToken: async () => "access" });
+}
+
+test('getPage(format:"text") requests text and returns the server text verbatim', async () => {
+  const state = {};
+  const client = makeClient(await spawn(state));
+
+  const result = await client.getPage(PAGE_UUID, "text");
+  assert.equal(state.lastInfoBody.format, "text", "the info request carried format:text");
+  assert.equal(result.success, true);
+  assert.equal(result.data.content, SERVER_TEXT, "returns the server's flat text unchanged");
+  // Deterministic placeholders are surfaced to the agent.
+  assert.ok(result.data.content.includes("[image]"));
+  assert.ok(result.data.content.includes("[table 2x3]"));
+  // No client-side markdown artifacts leaked in.
+  assert.ok(!result.data.content.includes("{{SUBPAGES}}"));
+  // Subpages still resolve for context.
+  assert.deepEqual(result.data.subpages, [{ id: CHILD_UUID, title: "Child" }]);
+});
+
+test('getPage default (no format) still returns markdown, not text', async () => {
+  const state = {};
+  const client = makeClient(await spawn(state));
+
+  const result = await client.getPage(PAGE_UUID);
+  assert.equal(state.lastInfoBody.format, undefined, "default read sends no format");
+  assert.ok(result.data.content.includes("Title line"), "markdown content converted client-side");
+  assert.notEqual(result.data.content, SERVER_TEXT);
+});
diff --git a/packages/mcp/test/mock/write-path-extensions-wiring.test.mjs b/packages/mcp/test/mock/write-path-extensions-wiring.test.mjs
new file mode 100644
index 00000000..ed9a7e22
--- /dev/null
+++ b/packages/mcp/test/mock/write-path-extensions-wiring.test.mjs
@@ -0,0 +1,181 @@
+// #502 caller-WIRING: end-to-end through a live Hocuspocus collab stack (same
+// harness style as markdown-patch-insert), driving the REAL client methods and
+// reading the persisted document back, so the test proves each write tool passes
+// the RIGHT importer options — not just that the shared wrapper can:
+//   - updatePageMarkdown (client.updatePage)      -> extensions OFF  (`$…$` literal, www not linked)
+//   - import_page_markdown (client.importPageMarkdown) -> DEFAULTS   (`$x^2$` -> math node, #328)
+// Mutating either caller's option flips the matching assertion (see the coder's
+// mutation note), so this file guards the wiring, not only the wrapper.
+import { test, after } from "node:test";
+import assert from "node:assert/strict";
+import http from "node:http";
+import { WebSocketServer } from "ws";
+import { Hocuspocus } from "@hocuspocus/server";
+import { DocmostClient } from "../../build/client.js";
+import { buildYDoc } from "../../build/lib/collaboration.js";
+import { serializeDocmostMarkdown } from "@docmost/prosemirror-markdown";
+
+const PAGE = "11111111-1111-4111-8111-111111111111";
+
+function findAll(node, type, acc = []) {
+  if (!node || typeof node !== "object") return acc;
+  if (node.type === type) acc.push(node);
+  if (Array.isArray(node.content)) for (const c of node.content) findAll(c, type, acc);
+  return acc;
+}
+function allText(node, acc = []) {
+  if (!node || typeof node !== "object") return acc.join("");
+  if (node.type === "text" && typeof node.text === "string") acc.push(node.text);
+  if (Array.isArray(node.content)) for (const c of node.content) allText(c, acc);
+  return acc.join("");
+}
+function hasLink(node) {
+  return findAll(node, "text").some((t) => t.marks?.some((m) => m.type === "link"));
+}
+
+function fragmentToJson(frag) {
+  const decodeNode = (el) => {
+    if (el.constructor.name === "YXmlText") {
+      const delta = el.toDelta();
+      return delta.map((d) => {
+        const node = { type: "text", text: d.insert };
+        if (d.attributes && Object.keys(d.attributes).length) {
+          node.marks = Object.entries(d.attributes).map(([type, attrs]) =>
+            attrs && typeof attrs === "object" && Object.keys(attrs).length
+              ? { type, attrs }
+              : { type },
+          );
+        }
+        return node;
+      });
+    }
+    const node = { type: el.nodeName };
+    const attrs = el.getAttributes();
+    if (attrs && Object.keys(attrs).length) node.attrs = attrs;
+    const children = [];
+    for (const child of el.toArray()) {
+      const decoded = decodeNode(child);
+      if (Array.isArray(decoded)) children.push(...decoded);
+      else children.push(decoded);
+    }
+    if (children.length) node.content = children;
+    return node;
+  };
+  const content = [];
+  for (const child of frag.toArray()) content.push(decodeNode(child));
+  return { type: "doc", content };
+}
+
+const openStacks = [];
+after(async () => {
+  await Promise.all(
+    openStacks.map(
+      ({ server, hocuspocus }) =>
+        new Promise((resolve) => {
+          server.close(() => {
+            Promise.resolve(hocuspocus.destroy?.()).finally(resolve);
+          });
+        }),
+    ),
+  );
+});
+
+async function spawnCollabStack(seedDoc) {
+  const state = { lastDoc: null };
+  const hocuspocus = new Hocuspocus({
+    quiet: true,
+    async onLoadDocument() {
+      return buildYDoc(seedDoc);
+    },
+    async onChange(data) {
+      try {
+        state.lastDoc = fragmentToJson(data.document.getXmlFragment("default"));
+      } catch {
+        /* ignore teardown-race decode errors */
+      }
+    },
+  });
+  const wss = new WebSocketServer({ noServer: true });
+  const server = http.createServer((req, res) => {
+    let raw = "";
+    req.on("data", (c) => (raw += c));
+    req.on("end", () => {
+      if (req.url === "/api/auth/login") {
+        res.writeHead(200, {
+          "Content-Type": "application/json",
+          "Set-Cookie": "authToken=t; Path=/; HttpOnly",
+        });
+        res.end(JSON.stringify({ success: true }));
+        return;
+      }
+      if (req.url === "/api/auth/collab-token") {
+        res.writeHead(200, { "Content-Type": "application/json" });
+        res.end(JSON.stringify({ data: { token: "collab-jwt" } }));
+        return;
+      }
+      res.writeHead(404, { "Content-Type": "application/json" });
+      res.end(JSON.stringify({ message: "not found" }));
+    });
+  });
+  server.on("upgrade", (request, socket, head) => {
+    if (!request.url || !request.url.startsWith("/collab")) {
+      socket.destroy();
+      return;
+    }
+    wss.handleUpgrade(request, socket, head, (ws) => {
+      hocuspocus.handleConnection(ws, request);
+    });
+  });
+  const baseURL = await new Promise((resolve) => {
+    server.listen(0, "127.0.0.1", () => {
+      resolve(`http://127.0.0.1:${server.address().port}/api`);
+    });
+  });
+  openStacks.push({ server, hocuspocus });
+  return { state, baseURL };
+}
+
+function seed() {
+  return {
+    type: "doc",
+    content: [
+      { type: "paragraph", attrs: { id: "p-id" }, content: [{ type: "text", text: "seed" }] },
+    ],
+  };
+}
+
+test("updatePageMarkdown wiring: extensions OFF — `$…$` literal, www not linked, https links", async () => {
+  const { state, baseURL } = await spawnCollabStack(seed());
+  const client = new DocmostClient(baseURL, "e@x.com", "pw");
+
+  await client.updatePage(PAGE, "cfg $x=1$ and www.host.com and https://ex.com");
+
+  assert.ok(state.lastDoc, "a document was persisted");
+  assert.equal(findAll(state.lastDoc, "mathInline").length, 0, "no phantom math from an agent write");
+  assert.ok(allText(state.lastDoc).includes("$x=1$"), "literal dollars preserved");
+  assert.ok(allText(state.lastDoc).includes("www.host.com"), "bare domain preserved as text");
+  // The explicit https URL still links (only the schemeless autolink is off).
+  const links = findAll(state.lastDoc, "text").filter((t) =>
+    t.marks?.some((m) => m.type === "link"),
+  );
+  assert.ok(links.some((t) => t.text?.includes("ex.com")), "explicit https still links");
+});
+
+test("import_page_markdown wiring: DEFAULTS — exported `$x^2$` re-imports AS a math node (#328)", async () => {
+  const { state, baseURL } = await spawnCollabStack(seed());
+  const client = new DocmostClient(baseURL, "e@x.com", "pw");
+
+  // A self-contained docmost markdown file whose body carries a math span (as the
+  // exporter emits it). import_page_markdown must import it with math ON.
+  const meta = { version: 1, pageId: PAGE, slugId: "s", title: "T", spaceId: "sp", parentPageId: null };
+  const fullMd = serializeDocmostMarkdown(meta, "energy is $x^2$ here", []);
+
+  await client.importPageMarkdown(PAGE, fullMd);
+
+  assert.ok(state.lastDoc, "a document was persisted");
+  assert.equal(
+    findAll(state.lastDoc, "mathInline").length,
+    1,
+    "the lossless round-trip is intact: math survives import_page_markdown",
+  );
+});
diff --git a/packages/mcp/test/unit/mcp-write-extensions-off.test.mjs b/packages/mcp/test/unit/mcp-write-extensions-off.test.mjs
new file mode 100644
index 00000000..2c4928c7
--- /dev/null
+++ b/packages/mcp/test/unit/mcp-write-extensions-off.test.mjs
@@ -0,0 +1,108 @@
+// #502: the two layered markdown extensions (`$…$` math, schemeless fuzzy
+// autolink) are decided PER CALLER of the shared write importer, not hardcoded in
+// the wrapper — because the callers need OPPOSITE behavior:
+//   - AGENT-authored plain markdown (updatePageMarkdown, patch_node/insert_node)
+//     -> extensions OFF: a `$…$` config span stays literal, a bare `www.host` is
+//     not autolinked, an explicit `https://…` still links.
+//   - FULL-FILE round-trip import (import_page_markdown, #328 lossless) ->
+//     DEFAULTS (extensions ON): an exported math node's `$x^2$` re-imports AS a
+//     math node, so the export→import pair is NOT broken.
+// This unit file pins the importer contract at each of those semantics. The
+// caller-WIRING (that each client method passes the right options) is pinned by
+// the collab-backed test in mock/write-path-extensions-wiring.test.mjs.
+import { test } from "node:test";
+import assert from "node:assert/strict";
+import { markdownToProseMirrorCanonical } from "../../build/lib/collaboration.js";
+import { importMarkdownFragment } from "../../build/lib/markdown-fragment.js";
+import {
+  markdownToProseMirror,
+  convertProseMirrorToMarkdown,
+} from "@docmost/prosemirror-markdown";
+
+const OFF = { parseMath: false, fuzzyLinkify: false };
+
+function findAll(node, type, acc = []) {
+  if (!node || typeof node !== "object") return acc;
+  if (node.type === type) acc.push(node);
+  if (Array.isArray(node.content)) for (const c of node.content) findAll(c, type, acc);
+  return acc;
+}
+function allText(node, acc = []) {
+  if (!node || typeof node !== "object") return acc.join("");
+  if (node.type === "text" && typeof node.text === "string") acc.push(node.text);
+  if (Array.isArray(node.content)) for (const c of node.content) allText(c, acc);
+  return acc.join("");
+}
+function hasLink(node) {
+  return findAll(node, "text").some((t) => t.marks?.some((m) => m.type === "link"));
+}
+
+// --- AGENT-write semantics (updatePageMarkdown): extensions OFF -----------------
+
+test("agent-write importer (OFF): `$…$` config stays literal, no math node", async () => {
+  const doc = await markdownToProseMirrorCanonical("export A=$FOO and B=$BAR done", OFF);
+  assert.equal(findAll(doc, "mathInline").length, 0);
+  assert.equal(allText(doc), "export A=$FOO and B=$BAR done");
+});
+
+test("agent-write importer (OFF): schemeless www NOT linked; explicit https STILL linked", async () => {
+  const bare = await markdownToProseMirrorCanonical("see www.example.com here", OFF);
+  assert.equal(hasLink(bare), false);
+  assert.equal(allText(bare), "see www.example.com here");
+
+  const explicit = await markdownToProseMirrorCanonical("see https://example.com here", OFF);
+  assert.equal(hasLink(explicit), true);
+});
+
+test("agent-write importer (OFF): heading + list structure preserved", async () => {
+  const doc = await markdownToProseMirrorCanonical("## Heading\n\n- one\n- two", OFF);
+  assert.equal(findAll(doc, "heading").length, 1);
+  assert.equal(findAll(doc, "bulletList").length, 1);
+});
+
+test("fragment importer (patch_node/insert_node) is OFF: `$x=1$` literal, https links", async () => {
+  const { blocks } = await importMarkdownFragment("cfg $x=1$ and https://ex.com");
+  const doc = { type: "doc", content: blocks };
+  assert.equal(findAll(doc, "mathInline").length, 0);
+  assert.equal(hasLink(doc), true);
+  assert.ok(allText(doc).includes("$x=1$"));
+});
+
+// --- FULL-FILE import semantics (import_page_markdown): DEFAULTS (math ON) ------
+
+test("import_page_markdown importer (DEFAULTS): `$x^2$` DOES create a math node", async () => {
+  // markdownToProseMirrorCanonical WITHOUT options == what import_page_markdown
+  // passes. Math must survive (this is the REAL importer, not the package default).
+  const doc = await markdownToProseMirrorCanonical("$x^2$");
+  assert.equal(findAll(doc, "mathInline").length, 1);
+  assert.equal(findAll(doc, "mathInline")[0].attrs.text, "x^2");
+});
+
+test("import_page_markdown (DEFAULTS): #328 lossless export->import keeps math (round-trip)", async () => {
+  // The exporter serializes a math node as readable `$x^2$`; re-importing through
+  // the REAL import_page_markdown importer (markdownToProseMirrorCanonical, no
+  // options) must yield a math node again and be byte-stable. Under the BUGGY code
+  // (canonical hardcoded parseMath:false) doc2 would be literal text -> this test
+  // would REDDEN.
+  const source = {
+    type: "doc",
+    content: [{ type: "paragraph", content: [{ type: "mathInline", attrs: { text: "x^2" } }] }],
+  };
+  const md1 = convertProseMirrorToMarkdown(source);
+  const doc2 = await markdownToProseMirrorCanonical(md1); // real import path, defaults
+  assert.equal(findAll(doc2, "mathInline").length, 1, "math survives the round-trip import");
+  const md2 = convertProseMirrorToMarkdown(doc2);
+  assert.equal(md2, md1, "export is byte-stable across the round-trip");
+});
+
+test("import_page_markdown (DEFAULTS): a schemeless www IS autolinked", async () => {
+  const doc = await markdownToProseMirrorCanonical("see www.example.com here");
+  assert.equal(hasLink(doc), true);
+});
+
+// --- Package default importer (editor/file-import/git-sync) is UNCHANGED --------
+
+test("PACKAGE default importer keeps math ON (editor/file/git-sync path)", async () => {
+  const doc = await markdownToProseMirror("$x^2$");
+  assert.equal(findAll(doc, "mathInline").length, 1);
+});
diff --git a/packages/prosemirror-markdown/src/lib/index.ts b/packages/prosemirror-markdown/src/lib/index.ts
index 6bcd3ef0..f5080ef3 100644
--- a/packages/prosemirror-markdown/src/lib/index.ts
+++ b/packages/prosemirror-markdown/src/lib/index.ts
@@ -25,6 +25,7 @@ export {
   markdownToProseMirror,
   markdownToProseMirrorSync,
 } from "./markdown-to-prosemirror.js";
+export type { MarkdownImportOptions } from "./markdown-to-prosemirror.js";
 
 // Foreign-markdown normalizer (#493): the input-liberal pre-pass that rewrites
 // GFM `[^id]` reference footnotes to canonical inline `^[body]`. Two variants:
diff --git a/packages/prosemirror-markdown/src/lib/markdown-to-prosemirror.ts b/packages/prosemirror-markdown/src/lib/markdown-to-prosemirror.ts
index f6ce4696..8755198f 100644
--- a/packages/prosemirror-markdown/src/lib/markdown-to-prosemirror.ts
+++ b/packages/prosemirror-markdown/src/lib/markdown-to-prosemirror.ts
@@ -7,7 +7,7 @@
  * natively through the collab gateway, so no websocket/Yjs write-path lives
  * here.
  */
-import { Marked } from "marked";
+import { Marked, Tokenizer } from "marked";
 import { parseHtmlDocument, generateJsonWith } from "./dom-parser.js";
 import type { TokenizerExtension, RendererExtension } from "marked";
 import { docmostExtensions } from "./docmost-schema.js";
@@ -231,19 +231,88 @@ function escapeFootnoteAttr(value: string): string {
   return String(value).replace(/&/g, "&amp;").replace(/"/g, "&quot;");
 }
 
-// Dedicated marked instance: default (GFM) options plus the `==` highlight
-// inline extension, the `$…$` / `$$…$$` math extensions (#293 canon #6), and the
-// `^[…]` inline-footnote extension (#293 canon #2). Constructed once at module
-// load so the extensions are registered exactly once and never mutate the global
-// `marked` singleton.
-const markedInstance = new Marked().use({
-  extensions: [
+/**
+ * Options controlling which of the two *layered* markdown extensions the
+ * canonical importer applies. Both default to `true`, so the human editor,
+ * file-import and git-sync paths keep their existing behavior byte-for-byte;
+ * ONLY the MCP markdown-write path opts OUT (see #502).
+ *
+ * The extensions are optional because they are the SOURCE of two silent
+ * corruptions when an AGENT writes plain prose/config as markdown:
+ *   - `parseMath`: a `$…$` span becomes a `mathInline` node. An agent writing a
+ *     config like `export A=$FOO and B=$BAR` gets `$FOO and B=$` silently turned
+ *     into a formula. With `parseMath:false` the `$` stays literal text (real
+ *     formulas go through `update_page_json` with `mathInline`/`mathBlock`).
+ *   - `fuzzyLinkify`: marked's GFM autolinker turns a SCHEMELESS `www.foo.com`
+ *     (and email) into a link. With `fuzzyLinkify:false` a schemeless domain
+ *     stays literal text; an EXPLICIT `https://…` STILL becomes a link (only the
+ *     fuzzy, schemeless autolink is suppressed).
+ */
+export interface MarkdownImportOptions {
+  /** Apply the `$…$` / `$$…$$` math extensions (default true). */
+  parseMath?: boolean;
+  /** Apply marked's GFM schemeless (fuzzy) autolinker (default true). */
+  fuzzyLinkify?: boolean;
+}
+
+/**
+ * `fuzzyLinkify:false` override of marked's built-in GFM `url` inline tokenizer.
+ *
+ * The stock tokenizer autolinks THREE shapes: a schemeless `www.host` domain, a
+ * bare email, and an EXPLICIT `scheme://…` URL. #502 wants only the last kept —
+ * a schemeless domain/email an agent typed as prose must stay literal text, but
+ * a deliberate `https://…` still links. We delegate to the original tokenizer
+ * and, when it matched, DROP the token (returning `undefined`, so the run stays
+ * literal text) unless the matched RAW text carries an explicit `scheme:` prefix.
+ * `www.`/email matches have no scheme in their raw text, so they are dropped;
+ * `https://…`/`ftp://…` keep their link.
+ */
+const SCHEME_PREFIX_RE = /^[a-zA-Z][a-zA-Z0-9+.-]*:/;
+const noFuzzyUrlTokenizer = {
+  url(this: any, src: string) {
+    const token = Tokenizer.prototype.url.call(this, src) as any;
+    if (!token) return token;
+    // Keep only explicit-scheme URLs; schemeless `www.`/email matches -> literal.
+    return SCHEME_PREFIX_RE.test(token.raw) ? token : undefined;
+  },
+};
+
+/**
+ * Build a dedicated `marked` instance for a given extension combination: default
+ * (GFM) options plus the `==` highlight and `^[…]` footnote inline extensions
+ * ALWAYS, the `$…$`/`$$…$$` math extensions only when `parseMath`, and the
+ * schemeless-autolink suppressor only when `!fuzzyLinkify`. Built on a private
+ * `Marked` instance so nothing leaks into the global `marked` singleton.
+ */
+function buildMarkedInstance(parseMath: boolean, fuzzyLinkify: boolean): Marked {
+  const extensions: (TokenizerExtension & RendererExtension)[] = [
     highlightMarkExtension,
-    mathInlineExtension,
-    mathBlockExtension,
     footnoteInlineExtension,
-  ],
-});
+  ];
+  if (parseMath) {
+    extensions.push(mathInlineExtension, mathBlockExtension);
+  }
+  const instance = new Marked().use({ extensions });
+  if (!fuzzyLinkify) {
+    instance.use({ tokenizer: noFuzzyUrlTokenizer as any });
+  }
+  return instance;
+}
+
+// Memoize one instance per (parseMath, fuzzyLinkify) combination so the
+// extensions are registered exactly once per combo (never on the global
+// singleton). The default `(true, true)` instance preserves the pre-#502
+// behavior exactly for the editor/file-import/git-sync paths.
+const markedInstanceCache = new Map<string, Marked>();
+function getMarkedInstance(parseMath: boolean, fuzzyLinkify: boolean): Marked {
+  const key = `${parseMath}:${fuzzyLinkify}`;
+  let instance = markedInstanceCache.get(key);
+  if (!instance) {
+    instance = buildMarkedInstance(parseMath, fuzzyLinkify);
+    markedInstanceCache.set(key, instance);
+  }
+  return instance;
+}
 
 // NOTE: this module no longer installs a module-level `global.window`/`document`
 // jsdom shim. The HTML->DOM passes below (bridgeTaskLists / applyCommentDirectives
@@ -302,7 +371,7 @@ const CODE_FENCE_RE = /^(\s*)(`{3,}|~{3,})/;
 // preprocess is sync. Keeping it sync lets a sync converter entry
 // (`markdownToProseMirrorSync`, used by the client's chat renderer which must
 // stay synchronous) share this exact logic with the async entry.
-function preprocessCallouts(markdown: string): string {
+function preprocessCallouts(markdown: string, markedInstance: Marked): string {
   // Defensive cap: skip preprocessing for pathologically large inputs.
   if (markdown.length > MAX_CALLOUT_PREPROCESS_BYTES) {
     return markdown;
@@ -956,7 +1025,7 @@ function applyCommentDirectives(html: string): string {
 // sups stay inert) rather than hang.
 const MAX_FOOTNOTE_ROUNDS = 10000;
 
-function assembleFootnotes(html: string): string {
+function assembleFootnotes(html: string, markedInstance: Marked): string {
   // Cheap early-out: nothing carries a footnote body -> nothing to assemble.
   if (!html.includes("data-fn-text")) return html;
   const document = parseHtmlDocument(html);
@@ -1082,8 +1151,18 @@ function stripEmptyParagraphs(node: any): any {
  * for every existing Node consumer). A sync entry is REQUIRED by the client's
  * chat renderer, which runs inside a React render/useMemo and cannot await.
  */
-export function markdownToProseMirrorSync(markdownContent: string): any {
-  const withCallouts = preprocessCallouts(markdownContent);
+export function markdownToProseMirrorSync(
+  markdownContent: string,
+  options?: MarkdownImportOptions,
+): any {
+  // Select the marked instance for this call's extension combination. Defaults
+  // (math + fuzzy autolink ON) preserve the editor/file-import/git-sync paths;
+  // the MCP markdown-write path passes both false (#502).
+  const markedInstance = getMarkedInstance(
+    options?.parseMath ?? true,
+    options?.fuzzyLinkify ?? true,
+  );
+  const withCallouts = preprocessCallouts(markdownContent, markedInstance);
   const html = markedInstance.parse(withCallouts) as string;
   // Materialize comment directives (#293 #9 attached textAlign; #5 standalone
   // subpages/pageBreak) while the comment nodes still exist, before generateJSON
@@ -1092,7 +1171,7 @@ export function markdownToProseMirrorSync(markdownContent: string): any {
   // #293 canon #2: assemble the doc-level footnote list from the `<sup
   // data-fn-text>` markers (from `^[…]` or the raw-HTML column form) before
   // generateJSON, so references + definitions materialize into the schema model.
-  const withFootnotes = assembleFootnotes(withAttrs);
+  const withFootnotes = assembleFootnotes(withAttrs, markedInstance);
   const bridged = bridgeTaskLists(withFootnotes);
   const doc = generateJsonWith(bridged, docmostExtensions);
   // Promote unambiguously-internal wiki-page links (`[t](/s/<space>/p/<slug>)`)
@@ -1110,6 +1189,7 @@ export function markdownToProseMirrorSync(markdownContent: string): any {
  */
 export async function markdownToProseMirror(
   markdownContent: string,
+  options?: MarkdownImportOptions,
 ): Promise<any> {
-  return markdownToProseMirrorSync(markdownContent);
+  return markdownToProseMirrorSync(markdownContent, options);
 }
diff --git a/packages/prosemirror-markdown/test/markdown-import-options.test.ts b/packages/prosemirror-markdown/test/markdown-import-options.test.ts
new file mode 100644
index 00000000..33700764
--- /dev/null
+++ b/packages/prosemirror-markdown/test/markdown-import-options.test.ts
@@ -0,0 +1,170 @@
+import { describe, expect, it } from 'vitest';
+// Import DIRECTLY from src (like math.test.ts) so we exercise the real
+// converter and its module-load jsdom setup.
+import { convertProseMirrorToMarkdown } from '../src/lib/markdown-converter.js';
+import { markdownToProseMirror } from '../src/lib/markdown-to-prosemirror.js';
+
+// ---------------------------------------------------------------------------
+// #502: the canonical importer is parameterized with `{ parseMath, fuzzyLinkify }`
+// (both DEFAULT true). The MCP markdown-WRITE path passes both false so an agent's
+// plain prose/config is imported LITERALLY:
+//   - parseMath:false  -> a `$…$` span stays literal text (no phantom mathInline)
+//   - fuzzyLinkify:false -> a SCHEMELESS `www.host`/email stays literal text; an
+//     EXPLICIT `https://…` STILL links (only the fuzzy autolink is suppressed).
+// The DEFAULTS (editor/file-import/git-sync) keep math + fuzzy autolink ON, so
+// this file also pins that the defaults are UNCHANGED.
+// ---------------------------------------------------------------------------
+
+const OFF = { parseMath: false, fuzzyLinkify: false } as const;
+
+// Collect the first paragraph's inline children (the common assertion target).
+function firstParaInline(doc: any): any[] {
+  const p = doc.content?.find((n: any) => n.type === 'paragraph');
+  return p?.content ?? [];
+}
+
+function findAll(node: any, type: string, acc: any[] = []): any[] {
+  if (!node || typeof node !== 'object') return acc;
+  if (node.type === type) acc.push(node);
+  if (Array.isArray(node.content)) {
+    for (const c of node.content) findAll(c, type, acc);
+  }
+  return acc;
+}
+
+// Flatten every text node's text (ignoring marks/structure) into one string.
+function allText(node: any, acc: string[] = []): string {
+  if (!node || typeof node !== 'object') return acc.join('');
+  if (node.type === 'text' && typeof node.text === 'string') acc.push(node.text);
+  if (Array.isArray(node.content)) {
+    for (const c of node.content) allText(c, acc);
+  }
+  return acc.join('');
+}
+
+describe('#502 importer options — extensions OFF (MCP write path)', () => {
+  it('a `$…$` config span stays literal text (no mathInline node)', async () => {
+    const md = 'export A=$FOO and B=$BAR done';
+    const doc = await markdownToProseMirror(md, OFF);
+    expect(findAll(doc, 'mathInline')).toHaveLength(0);
+    expect(allText(doc)).toBe('export A=$FOO and B=$BAR done');
+  });
+
+  it('a real-looking `$x=1$` span stays literal text', async () => {
+    const doc = await markdownToProseMirror('$x=1$', OFF);
+    expect(findAll(doc, 'mathInline')).toHaveLength(0);
+    expect(allText(doc)).toBe('$x=1$');
+  });
+
+  it('the reported `($ticket_lifetime=2592000)` config stays literal', async () => {
+    const doc = await markdownToProseMirror('($ticket_lifetime=2592000)', OFF);
+    expect(findAll(doc, 'mathInline')).toHaveLength(0);
+    expect(allText(doc)).toBe('($ticket_lifetime=2592000)');
+  });
+
+  it('a `$$…$$` block stays literal (no mathBlock node)', async () => {
+    const doc = await markdownToProseMirror('$$\nx^2\n$$', OFF);
+    expect(findAll(doc, 'mathBlock')).toHaveLength(0);
+    expect(allText(doc)).toContain('x^2');
+  });
+
+  it('a SCHEMELESS `www.example.com` is NOT autolinked', async () => {
+    const doc = await markdownToProseMirror('see www.example.com here', OFF);
+    const inline = firstParaInline(doc);
+    expect(inline.some((n: any) => n.marks?.some((m: any) => m.type === 'link'))).toBe(false);
+    expect(allText(doc)).toBe('see www.example.com here');
+  });
+
+  it('a bare dotted domain `gitea.vvzvlad.xyz` stays literal text', async () => {
+    const doc = await markdownToProseMirror('see gitea.vvzvlad.xyz here', OFF);
+    expect(findAll(doc, 'text').every((t: any) => !t.marks?.some((m: any) => m.type === 'link'))).toBe(true);
+  });
+
+  it('an EXPLICIT `https://…` STILL becomes a link', async () => {
+    const doc = await markdownToProseMirror('see https://example.com here', OFF);
+    const linked = firstParaInline(doc).find((n: any) =>
+      n.marks?.some((m: any) => m.type === 'link'),
+    );
+    expect(linked?.text).toBe('https://example.com');
+    const link = linked.marks.find((m: any) => m.type === 'link');
+    expect(link.attrs.href).toBe('https://example.com');
+  });
+
+  it('`foo_bar_baz` is not italicized (CommonMark, unaffected by options)', async () => {
+    const doc = await markdownToProseMirror('foo_bar_baz', OFF);
+    expect(findAll(doc, 'text').some((t: any) => t.marks?.some((m: any) => m.type === 'italic' || m.type === 'em'))).toBe(false);
+    expect(allText(doc)).toBe('foo_bar_baz');
+  });
+
+  it('block STRUCTURE (headings, lists, code fence) is preserved with extensions off', async () => {
+    const md = '## Heading\n\n- one\n- two\n\n```\ncode $x$ here\n```';
+    const doc = await markdownToProseMirror(md, OFF);
+    expect(findAll(doc, 'heading')).toHaveLength(1);
+    expect(findAll(doc, 'bulletList')).toHaveLength(1);
+    expect(findAll(doc, 'codeBlock')).toHaveLength(1);
+    // The `$x$` inside the code fence never becomes math regardless.
+    expect(findAll(doc, 'mathInline')).toHaveLength(0);
+  });
+});
+
+describe('#502 importer options — DEFAULTS unchanged (editor/file/git-sync)', () => {
+  it('DEFAULT: `$x^2$` DOES create a mathInline node (file-import unaffected)', async () => {
+    const doc = await markdownToProseMirror('$x^2$');
+    expect(findAll(doc, 'mathInline')).toHaveLength(1);
+    expect(findAll(doc, 'mathInline')[0].attrs.text).toBe('x^2');
+  });
+
+  it('DEFAULT: a schemeless `www.example.com` IS autolinked', async () => {
+    const doc = await markdownToProseMirror('see www.example.com here');
+    const linked = firstParaInline(doc).find((n: any) =>
+      n.marks?.some((m: any) => m.type === 'link'),
+    );
+    expect(linked?.text).toBe('www.example.com');
+  });
+
+  it('DEFAULT: explicitly passing {parseMath:true, fuzzyLinkify:true} equals no-options', async () => {
+    const a = await markdownToProseMirror('$x^2$ and www.foo.com');
+    const b = await markdownToProseMirror('$x^2$ and www.foo.com', {
+      parseMath: true,
+      fuzzyLinkify: true,
+    });
+    expect(JSON.stringify(b)).toBe(JSON.stringify(a));
+  });
+
+  it('round-trip export->import at the PACKAGE-DEFAULT layer keeps math (file-import / #328)', async () => {
+    // The package DEFAULT importer is what the server file-import path uses. A
+    // page holding real math is exported, then re-imported with DEFAULTS (math
+    // ON): the mathInline survives. (The tool-level import_page_markdown round-
+    // trip, which goes through mcp's markdownToProseMirrorCanonical, is pinned
+    // authoritatively in @docmost/mcp's mcp-write-extensions-off test.)
+    const source = {
+      type: 'doc',
+      content: [
+        { type: 'paragraph', content: [{ type: 'mathInline', attrs: { text: 'x^2' } }] },
+      ],
+    };
+    const md1 = convertProseMirrorToMarkdown(source);
+    const doc2 = await markdownToProseMirror(md1); // DEFAULTS -> math on
+    expect(findAll(doc2, 'mathInline')).toHaveLength(1);
+    const md2 = convertProseMirrorToMarkdown(doc2);
+    expect(md2).toBe(md1); // byte-stable
+  });
+});
+
+describe('#502 mutation guard', () => {
+  // If a future change silently flipped the MCP write path back to parseMath:true,
+  // the OFF assertion below would go RED — this pins the discriminating behavior.
+  it('with parseMath:true the same span DOES become math (proves the flag drives it)', async () => {
+    const on = await markdownToProseMirror('$x=1$', { parseMath: true, fuzzyLinkify: false });
+    expect(findAll(on, 'mathInline')).toHaveLength(1);
+    const off = await markdownToProseMirror('$x=1$', OFF);
+    expect(findAll(off, 'mathInline')).toHaveLength(0);
+  });
+
+  it('with fuzzyLinkify:true the same www domain DOES link (proves the flag drives it)', async () => {
+    const on = await markdownToProseMirror('www.example.com', { parseMath: false, fuzzyLinkify: true });
+    expect(findAll(on, 'text').some((t: any) => t.marks?.some((m: any) => m.type === 'link'))).toBe(true);
+    const off = await markdownToProseMirror('www.example.com', OFF);
+    expect(findAll(off, 'text').some((t: any) => t.marks?.some((m: any) => m.type === 'link'))).toBe(false);
+  });
+});