{"id":"00000000-0000-4000-8000-000000000003","task":"Send a Slack message to a channel as an app","domain":"slack.com","steps":["Ensure bot token has chat:write scope","Resolve channel id via conversations.list (channel NAMES are not accepted by chat.postMessage for private channels)","App must be invited to private channels: /invite @app","POST chat.postMessage with channel id + blocks"],"gotchas":["not_in_channel error means the bot needs inviting, not a scope change","Tier 3 rate limit ~50 msg/min per channel"],"contributor":"waymark-seed","created":"2026-06-11T00:00:00Z","attestations":{"success":13,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":"2026-06-13T15:04:51.826Z"},"success_rate":1,"effective_trust":0.761,"evidence_age_days":44,"trust_half_life_days":60,"verification":{"status":"sampled","method":"legacy-file-sample","at":"2026-06-13T18:40:37.260Z"},"url":"https://mcp.waymark.network/r/00000000-0000-4000-8000-000000000003"}