Telegram adapter: parse_mode not set for markdown messages

[buremba]

Bug

When sending messages with { markdown: ... } payload, the Telegram adapter does not set parse_mode on the Telegram API call. This causes Telegram to render the message as plain text, showing raw markdown characters (**bold**, _italic_) instead of formatted text.

Root Cause

In @chat-adapter/telegram, both postMessage and editMessage only set parseMode when a card is present:

const parseMode = card ? TELEGRAM_MARKDOWN_PARSE_MODE : void 0;

When the message payload is { markdown: "**hello**" }, the formatConverter.renderPostable() correctly processes the markdown text, but parseMode remains undefined because there's no card. The Telegram API then treats the text as plain.

Expected Behavior

parse_mode should be set to "Markdown" when the message contains a markdown field:

const parseMode = (card || (typeof message === "object" && message !== null && "markdown" in message))
  ? TELEGRAM_MARKDOWN_PARSE_MODE
  : void 0;

Affected Methods

• postMessage (line ~527 in dist)
• editMessage (line ~593 in dist)

Reproduction

const chat = new Chat({ adapters: { telegram: telegramAdapter } });
const thread = await chat.getThread("telegram", threadId);

// This renders as plain text with visible ** characters
await thread.post({ markdown: "**bold** and _italic_" });

// This works correctly (has card → parseMode is set)
await thread.post({ card: Card({ children: [CardText("hello")] }), fallbackText: "hello" });

Workaround

We're using bun patch to fix this locally:

-    const parseMode = card ? TELEGRAM_MARKDOWN_PARSE_MODE : void 0;
+    const parseMode = (card || (typeof message === "object" && message !== null && "markdown" in message)) ? TELEGRAM_MARKDOWN_PARSE_MODE : void 0;

Version

@chat-adapter/telegram@4.20.0