Slack

The Slack chatbot starts a workbench job when someone @mentions the bot in a channel. It connects through a Slack app in Socket Mode and replies in that channel. This is separate from the Slack tool, which the agent calls during a job.

Capabilities

The Slack chatbot connects via Socket Mode, an outbound websocket from Plural to Slack that streams channel messages and @mentions in real time. When someone @mentions the bot in a bound channel, Plural spawns a workbench job with the mention text as the prompt. The agent runs its investigation or task and replies in the same channel using Slack's chat API.

How it works:

• Receiving mentions — Slack delivers app_mention and message.* events to Plural over the Socket Mode websocket. The bot checks whether the message text contains its user ID (<@USER_ID>). If so, it creates a workbench job for the bound workbench with the message text as the prompt. If the mention is inside a thread and the parent message was also a bot mention, Plural queues the new mention as a follow-up prompt on the existing job rather than starting a new one.
• Replying — The spawned job automatically receives a Slack tool (the same connection used for the chatbot, backfilled on job start) so the agent can reply. The agent calls slack_post_message with the channel ID and, if replying in a thread, the original message's thread_ts. Agents can also call slack_react_to_message to add emoji reactions while the job is running.
• Threading — When a user @mentions the bot in a thread, Plural recognizes the parent message and either continues the same job (if the parent was a bot-triggered job) or starts a new job. Replies posted by the agent can use thread_ts to keep conversations grouped.

Authentication and scope requirements:

The setup guide details the two tokens needed for Socket Mode. Both are required; pasting the bot token into the app-level token field will not work.

• App-level token (xapp-) — Opens the Socket Mode websocket via apps.connections.open. Requires the connections:write scope.
• Bot user OAuth token (xoxb-) — Used for all Slack Web API calls after the websocket is open: reading channel history, posting messages, adding reactions, and resolving channel names. Requires bot token scopes including chat:write, channels:history, groups:history, reactions:read, and reactions:write.

The setup guide lists the full manifest and scope requirements for public channels, private channels, and direct messages.

Setup