Require explicit Discord mentions for agent-to-agent triggers

[mostlydev]

Summary

Discord-triggered agent handoffs are too permissive by default. Today, OpenClaw emits mention patterns that match plain agent-name variants, so sibling agents can be triggered in Discord without an actual @ mention.

Motivation

The current behavior makes cross-agent triggering too easy and increases the risk of accidental replies and feedback loops in shared channels.

Desired behavior

For Discord, require an explicit mention to trigger another agent.

Concretely:

• Native Discord mention syntax like <@123> / <@!123> should continue to work.
• Plain name matches such as tiverton should not count as a mention.
• Plain @username text that is not a native Discord mention should not be treated as sufficient.

Constraints

• Keep existing non-Discord text mention behavior unchanged unless the code path proves they are coupled.
• Preserve current guild/channel requireMention defaults and peer allowlists.
• Update tests to reflect the narrower Discord matcher.

Likely implementation area

• internal/driver/openclaw/config.go
• internal/driver/openclaw/config_test.go

Open questions

• If OpenClaw relies on text mention patterns for non-Discord platforms, we should scope the stricter change to Discord only.