diff --git a/docs/docs_map.md b/docs/docs_map.md
index 3588a72e5bce..560e5e94d575 100644
--- a/docs/docs_map.md
+++ b/docs/docs_map.md
@@ -7103,6 +7103,7 @@ Do not edit it by hand; run `pnpm docs:map:gen`.
 - Route: /plugins/sdk-channel-outbound
 - Headings:
   - H2: Adapter
+  - H2: Plain-text sanitization
   - H2: Delivery Evidence
   - H2: Existing outbound adapters
   - H2: Durable sends
diff --git a/docs/plugins/sdk-channel-outbound.md b/docs/plugins/sdk-channel-outbound.md
index 74048db450cb..83b3fd04c7b4 100644
--- a/docs/plugins/sdk-channel-outbound.md
+++ b/docs/plugins/sdk-channel-outbound.md
@@ -66,6 +66,24 @@ Only declare capabilities the native transport actually preserves. Cover
 each declared send, receipt, live-preview, and receive-ack capability with
 the contract helpers exported from this subpath.
 
+## Plain-text sanitization
+
+Use `sanitizeForPlainText(...)` when an outbound adapter needs to convert the
+supported HTML formatting tags into lightweight text markup. The default keeps
+the existing chat-style bold and strikethrough markers. Pass
+`{ style: "markdown" }` only when the channel reparses the result as Markdown:
+
+```ts
+import { sanitizeForPlainText } from "openclaw/plugin-sdk/channel-outbound";
+
+const chatText = sanitizeForPlainText(text);
+const markdownText = sanitizeForPlainText(text, { style: "markdown" });
+```
+
+The Markdown style uses `**bold**` and `~~strikethrough~~`; italic and inline
+code keep `_italic_` and backtick markers in both styles. Select the style at
+the channel boundary instead of rewriting marker text after sanitization.
+
 ## Delivery Evidence
 
 A `MessageReceipt` records the result returned by a channel adapter. Concrete
diff --git a/extensions/imessage/src/channel.ts b/extensions/imessage/src/channel.ts
index d5619eedfe6a..694d211efed5 100644
--- a/extensions/imessage/src/channel.ts
+++ b/extensions/imessage/src/channel.ts
@@ -351,7 +351,9 @@ export const imessagePlugin: ChannelPlugin<ResolvedIMessageAccount, IMessageProb
         chunker: chunkTextForOutbound,
         chunkerMode: "text",
         textChunkLimit: 4000,
-        sanitizeText: ({ text }) => sanitizeForPlainText(sanitizeOutboundText(text)),
+        // Native formatting consumes Markdown ranges, so preserve bold and strike semantics.
+        sanitizeText: ({ text }) =>
+          sanitizeForPlainText(sanitizeOutboundText(text), { style: "markdown" }),
         shouldSuppressLocalPayloadPrompt: ({ cfg, accountId, payload, hint }) =>
           shouldSuppressLocalIMessageExecApprovalPrompt({ cfg, accountId, payload, hint }),
         deliveryCapabilities: {
diff --git a/extensions/imessage/src/test-plugin.test.ts b/extensions/imessage/src/test-plugin.test.ts
index 54b0d627400c..ce8125863f59 100644
--- a/extensions/imessage/src/test-plugin.test.ts
+++ b/extensions/imessage/src/test-plugin.test.ts
@@ -12,6 +12,7 @@ import {
 import { afterEach, beforeEach, describe, expect, it } from "vitest";
 import { imessagePlugin } from "./channel.js";
 import { createIMessageTestPlugin } from "./imessage.test-plugin.js";
+import { extractMarkdownFormatRuns } from "./markdown-format.js";
 
 beforeEach(() => {
   resetFacadeRuntimeStateForTest();
@@ -112,6 +113,20 @@ describe("createIMessageTestPlugin", () => {
     });
   });
 
+  it("preserves sanitized HTML formatting as native ranges", () => {
+    const text = `<strong title="b>">bold</strong> <del data-note='s>'>strike</del>`;
+    const sanitized = imessagePlugin.outbound?.sanitizeText?.({ text, payload: { text } });
+
+    expect(sanitized).toBe("**bold** ~~strike~~");
+    expect(extractMarkdownFormatRuns(sanitized ?? "")).toEqual({
+      text: "bold strike",
+      ranges: [
+        { start: 0, length: 4, styles: ["bold"] },
+        { start: 5, length: 6, styles: ["strikethrough"] },
+      ],
+    });
+  });
+
   it("declares native iMessage voice memo TTS delivery", () => {
     expect(imessagePlugin.capabilities.tts?.voice).toStrictEqual({
       synthesisTarget: "audio-file",
diff --git a/extensions/telegram/src/outbound-adapter.ts b/extensions/telegram/src/outbound-adapter.ts
index 9297c1f1e319..b3dc71579b73 100644
--- a/extensions/telegram/src/outbound-adapter.ts
+++ b/extensions/telegram/src/outbound-adapter.ts
@@ -249,7 +249,9 @@ export function createTelegramOutboundAdapter(
     chunkerMode: "markdown",
     extractMarkdownImages: true,
     textChunkLimit: TELEGRAM_TEXT_CHUNK_LIMIT,
-    sanitizeText: ({ text }) => sanitizeForPlainText(sanitizeAssistantVisibleText(text)),
+    // Default Telegram delivery reparses this result as Markdown; use its bold and strike delimiters.
+    sanitizeText: ({ text }) =>
+      sanitizeForPlainText(sanitizeAssistantVisibleText(text), { style: "markdown" }),
     shouldSuppressLocalPayloadPrompt: options.shouldSuppressLocalPayloadPrompt,
     beforeDeliverPayload: options.beforeDeliverPayload,
     shouldTreatDeliveredTextAsVisible: options.shouldTreatDeliveredTextAsVisible,
diff --git a/extensions/telegram/src/telegram-outbound.test.ts b/extensions/telegram/src/telegram-outbound.test.ts
index 68fdcc1289ef..f73c57365e5b 100644
--- a/extensions/telegram/src/telegram-outbound.test.ts
+++ b/extensions/telegram/src/telegram-outbound.test.ts
@@ -2,7 +2,7 @@ import { chunkMarkdownTextWithMode } from "openclaw/plugin-sdk/reply-chunking";
 import { sendTextMediaPayload } from "openclaw/plugin-sdk/reply-payload";
 // Telegram tests cover telegram outbound plugin behavior.
 import { describe, expect, it, vi } from "vitest";
-import { splitTelegramHtmlChunks } from "./format.js";
+import { markdownToTelegramHtml, splitTelegramHtmlChunks } from "./format.js";
 import { telegramOutbound } from "./outbound-adapter.js";
 import { clearTelegramRuntime } from "./runtime.js";
 
@@ -47,6 +47,15 @@ describe("telegramPlugin outbound", () => {
     expect(telegramOutbound.sanitizeText?.({ text, payload: { text } })).toBe(text);
   });
 
+  it("uses Telegram markdown markers for sanitized HTML formatting", () => {
+    clearTelegramRuntime();
+    const text = `<strong title="b>">bold</strong> <del data-note='s>'>strike</del>`;
+    const sanitized = telegramOutbound.sanitizeText?.({ text, payload: { text } });
+
+    expect(sanitized).toBe("**bold** ~~strike~~");
+    expect(markdownToTelegramHtml(sanitized ?? "")).toBe("<b>bold</b> <s>strike</s>");
+  });
+
   it("preserves explicit HTML parse mode before chunking", () => {
     clearTelegramRuntime();
     const text = "<b>hi</b>";
diff --git a/src/infra/outbound/sanitize-text.test.ts b/src/infra/outbound/sanitize-text.test.ts
index c046d519beb9..0717ee108ea0 100644
--- a/src/infra/outbound/sanitize-text.test.ts
+++ b/src/infra/outbound/sanitize-text.test.ts
@@ -42,6 +42,17 @@ describe("sanitizeForPlainText", () => {
     expect(sanitizeForPlainText("<code>foo()</code>")).toBe("`foo()`");
   });
 
+  it("converts attributed inline tags without matching tag-name prefixes", () => {
+    const attributed = `<strong title="b>"><em title='i>'><del data-note="s>"><code class='c>'>x</code></del></em></strong>`;
+    expect(sanitizeForPlainText(attributed)).toBe("*_~`x`~_*");
+    expect(sanitizeForPlainText(attributed, { style: "markdown" })).toBe("**_~~`x`~~_**");
+    expect(
+      sanitizeForPlainText(
+        '<bold title="b">b</bold><strikeout title="s">s</strikeout><codebase>c</codebase>',
+      ),
+    ).toBe("bsc");
+  });
+
   // --- block elements -----------------------------------------------------
 
   it("converts <p> and <div> to newlines", () => {
@@ -51,6 +62,9 @@ describe("sanitizeForPlainText", () => {
   it("converts headings to bold text with newlines", () => {
     expect(sanitizeForPlainText("<h1>Title</h1>")).toBe("\n*Title*\n");
     expect(sanitizeForPlainText("<h3>Section</h3>")).toBe("\n*Section*\n");
+    expect(sanitizeForPlainText('<h2 title="section">Markdown</h2>', { style: "markdown" })).toBe(
+      "\n**Markdown**\n",
+    );
   });
 
   it("converts <li> to bullet points", () => {
diff --git a/src/infra/outbound/sanitize-text.ts b/src/infra/outbound/sanitize-text.ts
index eb4c0ca8f954..a61df4e6dcee 100644
--- a/src/infra/outbound/sanitize-text.ts
+++ b/src/infra/outbound/sanitize-text.ts
@@ -7,6 +7,10 @@ export { stripInternalRuntimeScaffolding };
 
 const HTML_TAG_RE = /<\/?[a-z][a-z0-9_-]*\b[^>]*>/gi;
 
+// Quoted attribute values may contain `>`; normalize convertible openers without leaking attribute text.
+const CONVERTIBLE_HTML_OPEN_TAG_RE =
+  /<(b|strong|i|em|s|strike|del|code|h[1-6]|li)(?=\s|>)(?:[^"'<>]|"[^"]*"|'[^']*')*>/gi;
+
 function stripRemainingHtmlTags(text: string): string {
   let previous: string;
   let current = text;
@@ -25,26 +29,30 @@ function stripRemainingHtmlTags(text: string): string {
  * are known to produce and avoids false positives on angle brackets in normal
  * prose (e.g. `a < b`).
  */
-export function sanitizeForPlainText(text: string): string {
+export function sanitizeForPlainText(text: string, options: { style?: "markdown" } = {}): string {
+  const boldMarker = options.style === "markdown" ? "**" : "*";
+  const strikeMarker = options.style === "markdown" ? "~~" : "~";
   const converted = stripInternalRuntimeScaffolding(text)
     // Preserve angle-bracket autolinks as plain URLs before tag stripping.
     .replace(/<((?:https?:\/\/|mailto:)[^<>\s]+)>/gi, "$1")
+    // Normalize attributes once; conversions below only need exact bare tag names.
+    .replace(CONVERTIBLE_HTML_OPEN_TAG_RE, "<$1>")
     // Line breaks
     .replace(/<br\s*\/?>/gi, "\n")
     // Block elements → newlines
     .replace(/<\/?(p|div)>/gi, "\n")
-    // Bold → WhatsApp/Signal bold
-    .replace(/<(b|strong)>(.*?)<\/\1>/gi, "*$2*")
+    // Bold → selected lightweight markup
+    .replace(/<(b|strong)>(.*?)<\/\1>/gi, `${boldMarker}$2${boldMarker}`)
     // Italic → WhatsApp/Signal italic
     .replace(/<(i|em)>(.*?)<\/\1>/gi, "_$2_")
-    // Strikethrough → WhatsApp/Signal strikethrough
-    .replace(/<(s|strike|del)>(.*?)<\/\1>/gi, "~$2~")
+    // Strikethrough → selected lightweight markup
+    .replace(/<(s|strike|del)>(.*?)<\/\1>/gi, `${strikeMarker}$2${strikeMarker}`)
     // Inline code
     .replace(/<code>(.*?)<\/code>/gi, "`$1`")
     // Headings → bold text with newline
-    .replace(/<h[1-6][^>]*>(.*?)<\/h[1-6]>/gi, "\n*$1*\n")
+    .replace(/<h[1-6]>(.*?)<\/h[1-6]>/gi, `\n${boldMarker}$1${boldMarker}\n`)
     // List items → bullet points
-    .replace(/<li[^>]*>(.*?)<\/li>/gi, "• $1\n");
+    .replace(/<li>(.*?)<\/li>/gi, "• $1\n");
 
   return stripRemainingHtmlTags(converted).replace(/\n{3,}/g, "\n\n");
 }