feat(telegram): add linkPreview config option

Add channels.telegram.linkPreview config to control whether link previews
are shown in outbound messages. When set to false, uses Telegram's
link_preview_options.is_disabled to suppress URL previews.

- Add linkPreview to TelegramAccountConfig type
- Add Zod schema validation for linkPreview
- Pass link_preview_options to sendMessage in send.ts and bot/delivery.ts
- Propagate linkPreview config through deliverReplies callers
- Add tests for link preview behavior

Fixes #1675

Co-Authored-By: Claude <noreply@anthropic.com>

src/config/types.telegram.ts

@@ -118,6 +118,8 @@ export type TelegramAccountConfig = {
   reactionLevel?: "off" | "ack" | "minimal" | "extensive";
   /** Heartbeat visibility settings for this channel. */
   heartbeat?: ChannelHeartbeatVisibilityConfig;
+  /** Controls whether link previews are shown in outbound messages. Default: true. */
+  linkPreview?: boolean;
 };
 
 export type TelegramTopicConfig = {

src/config/zod-schema.providers-core.ts

@@ -125,6 +125,7 @@ export const TelegramAccountSchemaBase = z
     reactionNotifications: z.enum(["off", "own", "all"]).optional(),
     reactionLevel: z.enum(["off", "ack", "minimal", "extensive"]).optional(),
     heartbeat: ChannelHeartbeatVisibilitySchema,
+    linkPreview: z.boolean().optional(),
   })
   .strict();
 

src/telegram/bot-message-dispatch.ts

@@ -151,6 +151,7 @@ export const dispatchTelegramMessage = async ({
           tableMode,
           chunkMode,
           onVoiceRecording: sendRecordVoice,
+          linkPreview: telegramCfg.linkPreview,
         });
       },
       onError: (err, info) => {

src/telegram/bot-native-commands.ts

@@ -348,6 +348,7 @@ export const registerTelegramNativeCommands = ({
                   messageThreadId: resolvedThreadId,
                   tableMode,
                   chunkMode,
+                  linkPreview: telegramCfg.linkPreview,
                 });
               },
               onError: (err, info) => {

src/telegram/bot/delivery.test.ts

@@ -108,4 +108,60 @@ describe("deliverReplies", () => {
       }),
     );
   });
+
+  it("includes link_preview_options when linkPreview is false", async () => {
+    const runtime = { error: vi.fn(), log: vi.fn() };
+    const sendMessage = vi.fn().mockResolvedValue({
+      message_id: 3,
+      chat: { id: "123" },
+    });
+    const bot = { api: { sendMessage } } as unknown as Bot;
+
+    await deliverReplies({
+      replies: [{ text: "Check https://example.com" }],
+      chatId: "123",
+      token: "tok",
+      runtime,
+      bot,
+      replyToMode: "off",
+      textLimit: 4000,
+      linkPreview: false,
+    });
+
+    expect(sendMessage).toHaveBeenCalledWith(
+      "123",
+      expect.any(String),
+      expect.objectContaining({
+        link_preview_options: { is_disabled: true },
+      }),
+    );
+  });
+
+  it("does not include link_preview_options when linkPreview is true", async () => {
+    const runtime = { error: vi.fn(), log: vi.fn() };
+    const sendMessage = vi.fn().mockResolvedValue({
+      message_id: 4,
+      chat: { id: "123" },
+    });
+    const bot = { api: { sendMessage } } as unknown as Bot;
+
+    await deliverReplies({
+      replies: [{ text: "Check https://example.com" }],
+      chatId: "123",
+      token: "tok",
+      runtime,
+      bot,
+      replyToMode: "off",
+      textLimit: 4000,
+      linkPreview: true,
+    });
+
+    expect(sendMessage).toHaveBeenCalledWith(
+      "123",
+      expect.any(String),
+      expect.not.objectContaining({
+        link_preview_options: expect.anything(),
+      }),
+    );
+  });
 });

src/telegram/bot/delivery.ts

@@ -36,8 +36,11 @@ export async function deliverReplies(params: {
   chunkMode?: ChunkMode;
   /** Callback invoked before sending a voice message to switch typing indicator. */
   onVoiceRecording?: () => Promise<void> | void;
+  /** Controls whether link previews are shown. Default: true (previews enabled). */
+  linkPreview?: boolean;
 }) {
-  const { replies, chatId, runtime, bot, replyToMode, textLimit, messageThreadId } = params;
+  const { replies, chatId, runtime, bot, replyToMode, textLimit, messageThreadId, linkPreview } =
+    params;
   const chunkMode = params.chunkMode ?? "length";
   const threadParams = buildTelegramThreadParams(messageThreadId);
   let hasReplied = false;
@@ -85,6 +88,7 @@ export async function deliverReplies(params: {
           messageThreadId,
           textMode: "html",
           plainText: chunk.text,
+          linkPreview,
         });
         if (replyToId && !hasReplied) {
           hasReplied = true;
@@ -180,6 +184,7 @@ export async function deliverReplies(params: {
             messageThreadId,
             textMode: "html",
             plainText: chunk.text,
+            linkPreview,
           });
           if (replyToId && !hasReplied) {
             hasReplied = true;
@@ -248,17 +253,22 @@ async function sendTelegramText(
     messageThreadId?: number;
     textMode?: "markdown" | "html";
     plainText?: string;
+    linkPreview?: boolean;
   },
 ): Promise<number | undefined> {
   const baseParams = buildTelegramSendParams({
     replyToMessageId: opts?.replyToMessageId,
     messageThreadId: opts?.messageThreadId,
   });
+  // Add link_preview_options when link preview is disabled.
+  const linkPreviewEnabled = opts?.linkPreview ?? true;
+  const linkPreviewOptions = linkPreviewEnabled ? undefined : { is_disabled: true };
   const textMode = opts?.textMode ?? "markdown";
   const htmlText = textMode === "html" ? text : markdownToTelegramHtml(text);
   try {
     const res = await bot.api.sendMessage(chatId, htmlText, {
       parse_mode: "HTML",
+      ...(linkPreviewOptions ? { link_preview_options: linkPreviewOptions } : {}),
       ...baseParams,
     });
     return res.message_id;
@@ -268,6 +278,7 @@ async function sendTelegramText(
       runtime.log?.(`telegram HTML parse failed; retrying without formatting: ${errText}`);
       const fallbackText = opts?.plainText ?? text;
       const res = await bot.api.sendMessage(chatId, fallbackText, {
+        ...(linkPreviewOptions ? { link_preview_options: linkPreviewOptions } : {}),
         ...baseParams,
       });
       return res.message_id;

src/telegram/send.ts

@@ -42,6 +42,8 @@ type TelegramSendOpts = {
   messageThreadId?: number;
   /** Inline keyboard buttons (reply markup). */
   buttons?: Array<Array<{ text: string; callback_data: string }>>;
+  /** Controls whether link previews are shown. Default: true (previews enabled). */
+  linkPreview?: boolean;
 };
 
 type TelegramSendResult = {
@@ -198,20 +200,21 @@ export async function sendMessageTelegram(
   });
   const renderHtmlText = (value: string) => renderTelegramHtmlText(value, { textMode, tableMode });
 
+  // Resolve link preview setting: explicit opt > config > default (enabled).
+  const linkPreviewEnabled = opts.linkPreview ?? account.config.linkPreview ?? true;
+  const linkPreviewOptions = linkPreviewEnabled ? undefined : { is_disabled: true };
+
   const sendTelegramText = async (
     rawText: string,
     params?: Record<string, unknown>,
     fallbackText?: string,
   ) => {
     const htmlText = renderHtmlText(rawText);
-    const sendParams = params
-      ? {
-          parse_mode: "HTML" as const,
-          ...params,
-        }
-      : {
-          parse_mode: "HTML" as const,
-        };
+    const sendParams = {
+      parse_mode: "HTML" as const,
+      ...(linkPreviewOptions ? { link_preview_options: linkPreviewOptions } : {}),
+      ...params,
+    };
     const res = await request(() => api.sendMessage(chatId, htmlText, sendParams), "message").catch(
       async (err) => {
         // Telegram rejects malformed HTML (e.g., unsupported tags or entities).