Message Split Skill#

Problem#

Many messaging channels (Feishu, Telegram, etc.) have a per-message character limit (~4000 chars for Feishu). When a response exceeds this limit, it either gets truncated or silently fails, leaving the user with no feedback.

Solution#

Before sending any message, check its length and split if necessary.

Usage#

python

def send_long_message(text, channel="{active_channel}"):
    """
    Send a message, splitting it into multiple chunks if it exceeds the length limit.

    Args:
        text: The message text to send
        channel: Target channel (feishu/telegram/discord/whatsapp/signal/imessage/openclaw-weixin)

    Returns:
        Number of chunks sent
    """
    MAX_LEN = 3600  # Feishu limit with margin
    CHUNK_HEADER = "[{i}/{total}]\n"

    if len(text) <= MAX_LEN:
        message(action="send", channel=channel, message=text)
        return 1

    chunks = split_text(text, MAX_LEN)
    total = len(chunks)

    for i, chunk in enumerate(chunks, 1):
        header = f"[{i}/{total}]\n" if total > 1 else ""
        message(action="send", channel=channel, message=header + chunk)

    return total

def split_text(text, max_len):
    """
    Split text into chunks of at most max_len characters.
    Attempts to split at sentence boundaries or line breaks for readability.
    """
    import re

    # Try to split at sentence-ending punctuation first
    sentence_split = re.split(r'(?<=[。！？.!?])\s+', text)

    chunks = []
    current = ""

    for sentence in sentence_split:
        if len(current) + len(sentence) + 1 <= max_len:
            current += (" " + sentence if current else sentence)
        else:
            if current:
                chunks.append(current)
            # If single sentence exceeds limit, split by words/characters
            if len(sentence) > max_len:
                for i in range(0, len(sentence), max_len - 100):
                    chunks.append(sentence[i:i + max_len - 100])
                current = ""
            else:
                current = sentence

    if current:
        chunks.append(current)

    return chunks

Channel Limits Reference#

ChannelMax chars (approx)NotesFeishu4000Hard limitTelegram4096Discord2000Embed limit 6000WhatsApp65000But relayed messages get truncatedSignal700Very lowiMessage~4000Via macOS relay

Notes#

• Always use MAX_LEN = 3600 as a safe default (leaves room for header)
• If channel is unknown, default to feishu behavior
• Splitting is done on word/sentence boundaries when possible to preserve readability
• Sequence headers [{i}/{total}] are only added when total > 1