Matrix Mentions Patch

Problem

OpenClaw Matrix plugin doesn't respond to @mentions in group rooms even when:

• The room is configured with requireMention: true
• The user correctly @mentions the bot (e.g., @runwheezy:matrix.biochao.cc)

Root Cause

In /home/bot/.openclaw/extensions/matrix/src/matrix/monitor/index.ts, the buildMentionRegexes function is called WITHOUT passing agentId:

// BUG: Missing agentId parameter
const mentionRegexes = core.channel.mentions.buildMentionRegexes(cfg);

Without agentId, the function can't resolve agent-specific mention patterns from config, causing mentions to never be detected.