Send text and optional file attachments to a Telegram chat. Supports reply-to (including forum topics and channel discussion groups), parse_mode: classic markdown/html/auto (entities) or rich (Rich Message document; dialect auto-detected). parse_mode=rich cannot be combined with files. File attachments as http(s) URLs, local paths, or data: URIs. When files are provided, the message text becomes a caption. For channel posts with reply_to_id, automatically posts in the linked discussion group. schedule_date (ISO 8601, must be in the future) queues the message instead of delivering it now, so the result carries status='scheduled' plus scheduled and schedule_date. save_as_draft=true saves the text as the chat's draft instead of sending it (empty message clears the draft; user sessions only, bots cannot; text-only, so no files, no parse_mode='rich', no schedule_date). Success: dict with message_id, date, chat, text, status='sent', and sender info (rich messages also set rich=true and rich_format). Error: dict with ok=false and error string. Use send_message to create new messages; use edit_message to modify existing ones. Use send_message_to_phone when targeting a phone number instead of a chat_id. Full documentation: https://github.com/leshchenko1979/fast-mcp-telegram/blob/main/docs/Tools-Reference.md