diff --git a/src/agents/system-prompt.test.ts b/src/agents/system-prompt.test.ts
index 5e7f3c6016e7..63f146f25d96 100644
--- a/src/agents/system-prompt.test.ts
+++ b/src/agents/system-prompt.test.ts
@@ -1023,6 +1023,9 @@ describe("buildAgentSystemPrompt", () => {
     expect(telegramPrompt).toContain("pull quotes");
     expect(telegramPrompt).toContain('task lists via `<input type="checkbox"/>` inside `<li>`');
     expect(telegramPrompt).toContain("anchors/in-message links");
+    expect(telegramPrompt).toContain(
+      "formulas (inline `<tg-math>LaTeX</tg-math>`, block `<tg-math-block>LaTeX</tg-math-block>`; not `$...$` or `\\(...\\)`)",
+    );
     expect(telegramPrompt).toContain("maps/collages/slideshows");
     expect(telegramPrompt).toContain("use `<details>`, not legacy `<blockquote expandable>`");
     expect(telegramPrompt).toContain("use `<ul><li>...</li></ul>`, not literal bullet characters");
diff --git a/src/agents/system-prompt.ts b/src/agents/system-prompt.ts
index 6667120ba4f6..337dcc56cd6c 100644
--- a/src/agents/system-prompt.ts
+++ b/src/agents/system-prompt.ts
@@ -527,7 +527,7 @@ function buildMessagingSection(params: {
       : "- Reply in current session → automatically routes to the source channel (Signal, Telegram, etc.)",
     telegramRuntime
       ? telegramRichTextEnabled
-        ? '- Telegram rich text is available. Use Bot API 10.1 rich formatting in visible message text when it improves clarity: headings, tables with alignment/captions/spans, blockquotes, pull quotes, `<details><summary>...</summary>...</details>`, dividers, `<sup>/<sub>`, `<mark>`, spoilers, `<ul>/<ol>` lists with `<li>` items, task lists via `<input type="checkbox"/>` inside `<li>`, code blocks, footnotes/references, formulas, anchors/in-message links, custom emoji, maps/collages/slideshows, and standalone rich media blocks such as `<img src="https://..."/>`. This is not legacy MarkdownV2/parse_mode; OpenClaw renders Telegram-safe rich messages. For collapsible content, use `<details>`, not legacy `<blockquote expandable>`; for structured bullets, use `<ul><li>...</li></ul>`, not literal bullet characters. Media tags are blocks, not inline prose; use captions/credits when helpful; button labels are plain text only; send normal attachments through explicit media delivery.'
+        ? '- Telegram rich text is available. Use Bot API 10.1 rich formatting in visible message text when it improves clarity: headings, tables with alignment/captions/spans, blockquotes, pull quotes, `<details><summary>...</summary>...</details>`, dividers, `<sup>/<sub>`, `<mark>`, spoilers, `<ul>/<ol>` lists with `<li>` items, task lists via `<input type="checkbox"/>` inside `<li>`, code blocks, footnotes/references, formulas (inline `<tg-math>LaTeX</tg-math>`, block `<tg-math-block>LaTeX</tg-math-block>`; not `$...$` or `\\(...\\)`), anchors/in-message links, custom emoji, maps/collages/slideshows, and standalone rich media blocks such as `<img src="https://..."/>`. This is not legacy MarkdownV2/parse_mode; OpenClaw renders Telegram-safe rich messages. For collapsible content, use `<details>`, not legacy `<blockquote expandable>`; for structured bullets, use `<ul><li>...</li></ul>`, not literal bullet characters. Media tags are blocks, not inline prose; use captions/credits when helpful; button labels are plain text only; send normal attachments through explicit media delivery.'
         : "- Telegram rich messages are disabled for this bot/account. Do not claim Bot API 10.1 tables, details blocks, rich media, formulas, or other rich-message-only formatting are enabled. Standard Telegram HTML formatting is available; ask the owner to enable Telegram rich messages for this channel/account."
       : "",
     "- Cross-session messaging → use sessions_send(sessionKey, message)",