Slack trigger

Starts the automation when someone in Slack uses one of your Slack app's slash commands or shortcuts, or mentions the app. In the trigger picker it is Slack, under Integration Triggers.

Fields

Field	Required	Description
Connection	Yes	The Slack connection whose app defines the command or shortcut, or is mentioned.
Event	Yes	What in Slack fires the trigger.

Events

Event	Fires when	Its own fields
Slash Command	Someone uses the command.	Command—the command as the Slack app defines it, such as /weather. Case and the leading slash don't matter.
Global Shortcut	Someone picks the shortcut from Slack's shortcut menu or search.	Callback ID—the shortcut's Callback ID as the Slack app defines it, such as open_ticket.
Message Shortcut	Someone picks the shortcut from a message's More actions menu.	Callback ID—as for a global shortcut.
App Mention	Someone mentions the app by its @name in a channel or thread the app is in.	None.

Setting it up in Slack

Slack doesn't learn about a command, shortcut or mention from Esca; you set it up in the Slack app, and the trigger shows what to enter: for a command or shortcut, once its Command or Callback ID is filled in.

For a slash command:

1. In the app's settings at api.slack.com/apps, open Slash Commands and choose Create New Command.
2. Enter the command, and as its Request URL the URL the trigger shows. Every command gets the same URL, which the Slack connection also shows.
3. Save the command.

For a shortcut:

1. In the app's settings, open Interactivity & Shortcuts and turn Interactivity on, with the Request URL the trigger shows. An app has one Interactivity Request URL, which approvals in Slack use too, so it may already be set.
2. Choose Create New Shortcut, pick Global or On messages to match the event, and enter the Callback ID.
3. Save the shortcut.

For a mention:

1. In the app's settings, open Event Subscriptions and turn Enable Events on.
2. Enter as its Request URL the URL the trigger shows, which the Slack connection also shows. Slack checks the URL as soon as you enter it, so the Slack connection must already hold the app's Signing Secret.
3. Under Subscribe to bot events, add app_mention, and save.
4. Slack asks you to reinstall the app, since the event needs the app_mentions:read scope. Click Connect on the Slack connection instead, which reinstalls it.

The app hears only mentions in conversations it is in; Slack offers to invite it when someone mentions it anywhere else. A message in a direct message with the app isn't a mention, even one that names it.

Slash commands and shortcuts both need the commands scope. If the Slack connection was made before the Slack trigger existed, click Connect on it again, once, so the install grants it.

Slack signs every request with the app's signing secret, and the trigger runs only for a request that verifies against it, so the Slack connection must hold the Signing Secret. A request that fails verification, or that arrives more than five minutes after Slack signed it, starts nothing.

Several automations can listen for the same command, shortcut or mention; each runs. A trigger only hears requests from the workspace its connection is installed in, even when the same app is installed in others.

A mention by a bot, including the app's own replies, starts nothing, so a reply that mentions the app can't start the automation again. Slack sends a mention again when it hasn't heard back within 3 seconds; one it sends again doesn't run the automation twice.

Output

The output of a slash command or shortcut names who used it, in user.id and user.name, and the workspace, in team.id and team.domain, and carries Slack's trigger_id for opening a modal. It expires 3 seconds after the request, and the automation runs after Esca has acknowledged the request, so a run may be too late to use it.

Event	Its own output
Slash Command	command, the command used; text, what was typed after it, empty when nothing was; channel.id and channel.name, where it was used; response_url.
Global Shortcut	callback_id.
Message Shortcut	callback_id; channel.id and channel.name; message, the message the shortcut was used on—its text, its author's ID in user, its ts, and its thread_ts when it is a reply in a thread; response_url.
App Mention	text, what was said, as Slack sends it: every mention in it, the app's own included, is written <@ and the person's user ID >, such as <@U0LAN0Z89>; user.id, channel.id and team.id, since Slack sends no names with a mention; ts, the mention's own; thread_ts, the thread to reply in—the one the mention is in, or the mention itself when it isn't in one; bot_user_id, the app's own user ID, which marks the app's mentions in text and its own messages in a thread. There is no trigger_id or response_url.

Replying

Esca acknowledges the request at once and shows nothing in Slack, so the reply is the automation's to send:

• Use the Slack action's Respond, which replies through response_url to only the person who used the command or shortcut, or to the whole channel, up to five times within 30 minutes.
• Use the Slack action's Send Message to post to channel.id or user.id. A global shortcut has no channel or response_url, so this is how one replies.
• Answer a mention with Send Message to channel.id, with Reply in Thread set to thread_ts. The answer sits under the question, where the conversation can go on.

A chat assistant

A mention makes a natural assistant: the question stays in the channel, the answer arrives in its thread, and each later mention in the thread brings the conversation so far.

1. Slack trigger, App Mention.
2. Slack action, Add Reaction eyes to channel.id and ts, so the person sees at once that the app is on it.
3. Slack action, Get Message with channel.id and ts. A mention in a thread reads the whole thread, so the next step has the conversation and not only the latest message.
4. An AI step that answers from the thread and text. Tell it that it is <@bot_user_id>, with the variable in place of bot_user_id, so that it knows which mentions are of itself and which messages in the thread are its own earlier answers. Since people appear as <@ and their ID >, it can mention someone back the same way.
5. Slack action, Send Message to channel.id with Reply in Thread set to thread_ts.
6. Slack action, Remove Reaction eyes.

Deliveries

Every request the trigger receives is recorded on its Deliveries screen, from which it can be replayed. A replay is signed afresh, so it verifies like the original did.