Bug Description

In OpenClaw >= 2026.4.12, the empty-body guard in get-reply checks only baseBodyFinal (the current message body) instead of baseBodyForPrompt (which includes InboundHistory context). This breaks Feishu group chat with requireMention: true:

1. User sends messages in a group (without @bot)
2. User @bot the bot without any additional text (e.g., just selecting @bot from the member list)
3. Bot receives the mention, strips the bot mention text → baseBodyFinal becomes empty string ""
4. The InboundHistory (pending group history) IS populated with prior messages, but the guard at line ~2212 checks hasUserBody = baseBodyFinal.trim().length > 0 which is false
5. Bot returns "I didn't receive any text in your message. Please resend or add a caption." instead of processing the InboundHistory context

If the user adds any text alongside the @mention (e.g., "@bot hello"), baseBodyFinal is non-empty and everything works correctly — the bot can see prior group messages via InboundHistory.

Affected Versions

• Broken: 2026.4.12 through 2026.4.23 (latest)
• Working: 2026.4.11

Root Cause

In dist/get-reply-1y8kEvLp.js (2026.4.23), around line 2206:

// 2026.4.23 — only checks current message body, ignores InboundHistory
const hasUserBody = baseBodyFinal.trim().length > 0 || softResetTail.length > 0;
if (!hasUserBody && !hasMediaAttachment) {
    return { text: "I didn't receive any text..." };
}

Previously in 2026.4.11 (dist/get-reply-bONH39Y6.js), around line 1931:

// 2026.4.11 — checks the full prompt including InboundHistory context
const baseBodyForPrompt = isBareSessionReset ? baseBodyFinal : [inboundUserContext, baseBodyFinal].filter(Boolean).join("\n\n");
const baseBodyTrimmed = baseBodyForPrompt.trim();
if (!baseBodyTrimmed && !hasMediaAttachment) {
    return { text: "I didn't receive any text..." };
}

The refactoring that introduced this also split baseBodyForPrompt from the empty check into hasUserBody/effectiveBaseBody, likely to improve the media-caption fallback path. However, it inadvertently decoupled the empty guard from InboundHistory context.

Expected Behavior

When InboundHistory contains pending group chat entries, the bot should process the request even if the current @mention message body is empty. The @bot alone (without text) is a valid trigger in group chats.

Environment

• Plugin: openclaw-lark 2026.4.8 (official Feishu plugin by Lark team)
• Channel config: requireMention: true, groupPolicy: "allowlist"
• Feishu backend: Message receive mode set to "receive all group messages"
• OS: macOS (arm64)