openclaw - 💡(How to fix) Fix [Bug]: @openclaw/slack v2026.5.18 silently drops non-mention messages from private channels (requireMention: false ignored)

Problem

In @openclaw/slack v2026.5.18 (Socket Mode), non-mention messages in private Slack channels reach Slack but never route to the agent session, despite Socket Mode reporting connected and the channel being correctly resolved.

@-mentions and DMs both work; only non-mention messages in private channels are silently dropped.

This appears to be a regression — earlier versions handled this delivery path, and the documented requireMention: false config option is no longer functioning as described.

Environment

• OpenClaw 2026.5.18
• @openclaw/slack plugin v2026.5.18
• macOS host, Node 22.22.2
• Single private Slack channel, member count: 1 agent + 2 humans
• Channel config: channels.slack.channels.<channelId>.requireMention: false
• Socket Mode connection: reported healthy; channel resolution log line confirms [slack] channels resolved: <channelId>→<channelName>

Reproduction

1. Configure a private Slack channel in channels.slack.channels.<channelId> with requireMention: false.
2. Restart the gateway. Confirm in logs: [slack] channels resolved: <channelId>→<channelName>.
3. Have a human post a plain message in the channel (no @-mention of the bot).
4. Observe in Slack channel history: message is visible.
5. Observe in OpenClaw gateway log: no inbound event for that message arrives at all.
6. Have the same human post an @-mention message in the same channel.
7. Observe in gateway log: inbound event arrives, agent replies normally.

Diagnostic detail

openclaw status reports the Slack channel as healthy. The auth layer is fine; the event-routing layer is silently dropping the messages.

What we tried (none restored non-mention delivery)

• Gateway restart
• Explicit plugins.allow: ["slack", "anthropic", "duckduckgo"] whitelist
• Channel session reset in sessions.json
• Toggling requireMention between true and false
• Re-resolving the channel via the API

Schema observation (possibly related)

The OpenClaw docs at docs/channels/slack.md document an allow: true field on the per-channel config, but the JSON-schema validator in v2026.5.18 rejects that field. Only requireMention and users are accepted. Worth checking whether the docs are stale or whether the schema dropped a field by accident in the 2026.5.18 release — could be related to this delivery regression.

Workaround

requireMention: true is the working state. All channel interactions require @-mention. DMs continue to work normally.

Impact

For small private channels that function socially as DMs (e.g. a 2-human + 1-agent working channel), requiring @-mention on every message is a high social-friction tax — users want the agent to participate naturally without being summoned every turn.

Happy to help

I can provide gateway logs + Slack channel-history correlations privately if helpful.