Slack

You can connect Guild to your Slack workspace. The Slack integration gives your agents authenticated access to the Slack Web API. This allows your agents to monitor channels, respond to user messages, and post automated updates.

Slack is a dynamically resolved integration. Its operations are resolved from Slack’s OpenAPI specification at runtime, so agents do not import a Slack-specific package. Register the operations you need with guildServiceTool("slack", ...) from the Guild Agents SDK.

Feature overview

What your Guild Slack integration can do depends entirely on which agents you choose to connect. The integration is highly flexible. The exact capabilities depend on how you configure your Guild agents. Here are a few examples:

Ask questions

File feature requests

Post rule-based alerts

Authentication

Type: OAuth 2.02
Token management: Slack tokens don’t expire — no refresh needed

Setup

Open Credentials

Go to Credentials in Guild.

Connect Slack

Click Slack and authorize Guild in your workspace.

Create a trigger

Go to triggers and create a new trigger.

Invite the agent

Invite the Slack agent to channels where you want message events. app_mention works without an invite.

OAuth scopes

Category	Scopes
Channels	`channels:history`, `channels:read`
Groups	`groups:history`, `groups:read`
Messages	`chat:write`, `app_mentions:read`
Reactions	`reactions:read`, `reactions:write`

Usage

Slack is dynamically resolved, so you do not import a Slack-specific package. Register the operations your agent needs with guildServiceTool() from the Guild Agents SDK, passing slack as the service name. Guild resolves each operation against Slack’s OpenAPI specification and injects credentials through the connected workspace account. Name each tool with the slack_ prefix to match the underlying operation — for example, the chat_post_message operation becomes the slack_chat_post_message tool.

import { guildServiceTool, llmAgent } from "@guildai/agents-sdk"
import { z } from "zod"

const slack_chat_post_message = guildServiceTool("slack", {
  description: "Post a message to a Slack channel.",
  inputSchema: z.object({
    channel: z.string(),
    text: z.string(),
  }),
  outputSchema: z.object({
    ok: z.boolean(),
    ts: z.string().optional(),
  }),
})

export default llmAgent({
  description: "An agent that manages Slack messages",
  tools: { slack_chat_post_message },
})

Selecting specific tools

Agents perform better with fewer tools. Register only the operations your agent needs — add each one as its own guildServiceTool("slack", ...) entry:

import { guildServiceTool, llmAgent } from "@guildai/agents-sdk"
import { z } from "zod"

const slack_chat_post_message = guildServiceTool("slack", {
  description: "Post a message to a Slack channel.",
  inputSchema: z.object({ channel: z.string(), text: z.string() }),
})

const slack_conversations_list = guildServiceTool("slack", {
  description: "List channels in the workspace.",
  inputSchema: z.object({ limit: z.number().optional() }),
})

const slack_conversations_history = guildServiceTool("slack", {
  description: "Fetch a channel's message history.",
  inputSchema: z.object({ channel: z.string(), limit: z.number().optional() }),
})

export default llmAgent({
  description: "An agent that posts Slack updates",
  tools: {
    slack_chat_post_message,
    slack_conversations_list,
    slack_conversations_history,
  },
})

API endpoints

Messages

Operation	Method	Path
`chat_post_message`	POST	`/chat.postMessage`
`chat_update`	POST	`/chat.update`
`chat_delete`	POST	`/chat.delete`
`chat_post_ephemeral`	POST	`/chat.postEphemeral`
`chat_schedule_message`	POST	`/chat.scheduleMessage`
`chat_scheduled_messages_list`	GET	`/chat.scheduledMessages.list`
`chat_delete_scheduled_message`	POST	`/chat.deleteScheduledMessage`
`chat_get_permalink`	GET	`/chat.getPermalink`

Conversations

Operation	Method	Path
`conversations_list`	GET	`/conversations.list`
`conversations_info`	GET	`/conversations.info`
`conversations_history`	GET	`/conversations.history`
`conversations_replies`	GET	`/conversations.replies`
`conversations_members`	GET	`/conversations.members`
`conversations_join`	POST	`/conversations.join`
`conversations_leave`	POST	`/conversations.leave`
`conversations_invite`	POST	`/conversations.invite`
`conversations_archive`	POST	`/conversations.archive`
`conversations_unarchive`	POST	`/conversations.unarchive`
`conversations_set_topic`	POST	`/conversations.setTopic`
`conversations_set_purpose`	POST	`/conversations.setPurpose`

Reactions

Operation	Method	Path
`reactions_add`	POST	`/reactions.add`
`reactions_get`	GET	`/reactions.get`
`reactions_list`	GET	`/reactions.list`
`reactions_remove`	POST	`/reactions.remove`

Files

Operation	Method	Path
`files_info`	GET	`/files.info`
`files_delete`	POST	`/files.delete`

Pins

Operation	Method	Path
`pins_add`	POST	`/pins.add`
`pins_list`	GET	`/pins.list`
`pins_remove`	POST	`/pins.remove`

Reminders

Operation	Method	Path
`reminders_add`	POST	`/reminders.add`
`reminders_complete`	POST	`/reminders.complete`
`reminders_delete`	POST	`/reminders.delete`
`reminders_list`	GET	`/reminders.list`

Users

Operation	Method	Path
`users_lookup_by_email`	GET	`/users.lookupByEmail`
`users_profile_get`	GET	`/users.profile.get`

User groups

Operation	Method	Path
`usergroups_create`	POST	`/usergroups.create`
`usergroups_list`	GET	`/usergroups.list`
`usergroups_update`	POST	`/usergroups.update`
`usergroups_users_list`	GET	`/usergroups.users.list`
`usergroups_users_update`	POST	`/usergroups.users.update`

Team

Operation	Method	Path
`emoji_list`	GET	`/emoji.list`

Webhook events

Slack uses an agent-scoped webhook model — a single webhook receives all events and Guild routes them to matching triggers.

Event	Description
`app_mention`	The Slack agent is mentioned in a channel.
`app_uninstalled`	The Slack workspace uninstalls the Slack agent.
`member_joined_channel`	A user joins a public or private channel.
`message.channels`	A user posts a message in a public channel.
`message.groups`	A user posts a message in a private channel.
`reaction_added`	A user adds an emoji reaction to a message.
`reaction_removed`	A user removes an emoji reaction from a message.
`tokens_revoked`	The workspace revokes API tokens for the Slack agent.

Events can be filtered to specific channels by setting channel_ids in the service configuration. Messages from the Slack agent itself are automatically excluded to prevent feedback loops.

How the integration works

Guild uses Slack’s OAuth v2 flow. When you connect Slack, Guild receives a bot access token scoped to the installed workspace.

Long-lived token — Slack bot tokens do not expire. Guild stores the token once; no refresh flow is required.
Bot only — Guild does not receive a user token. All API calls run as the bot, not as the installing user.
One workspace per connection — Each Slack install maps to one team_id and one bot token.
Bot user ID — Guild captures this at install time and uses it to filter out the agent’s own messages and prevent feedback loops.

Inbound events

Slack pushes events to a single agent webhook. Guild validates payloads with HMAC-SHA256 (X-Slack-Signature and X-Slack-Request-Timestamp), deduplicates by event_id, and routes events to matching triggers. Use channel_ids in trigger service_config to limit which channels fire your agent. An empty channel_ids array matches all channels.

Outbound API calls

Agents call the Slack Web API through Guild’s proxy, which injects the bot token. The runtime exposes operations as slack_* tools (for example, slack_chat_post_message). Messages always appear from the bot — you cannot post as a specific user. Guild scrubs URLs, thumbnails, avatars, and permalinks from webhook payloads before they reach agents to reduce token usage.

Session link tracing

When an agent posts a message to Slack via chat.postMessage, Guild automatically appends a link back to the originating workspace session — unless the message already contains a link to that session. This makes it easy to trace any Slack update back to the agent run that produced it. The link is added as a short footer line. If you want to suppress it for a specific message, include the session URL in the message body yourself.

Session links support graded disclosure. When you click a Slack session link, you no longer hit a 404 if you are logged out or lack workspace access. Guild responds based on your authorization state:

If you have access, Guild redirects you to the canonical workspace session URL.
If you are logged in but lack access, Guild shows the name and type of the account that owns the session.
If you are logged out, Guild confirms the session exists and prompts you to sign in.

Link and media unfurling

To keep Slack channels clean, Guild disables link and media unfurling by default on every message an agent posts via chat.postMessage. Unfurling generates automatic previews of links and media, which can clutter channels and add noise. Guild sets unfurl_links and unfurl_media to false on outgoing message payloads. This applies to all posted messages, whether or not a session link tracing footer is appended. An agent can override either default by passing unfurl_links: true or unfurl_media: true in the message payload. Guild respects the explicit value and does not disable that unfurling.

Limitations

You must invite the Slack agent to channels to receive message events (app_mention works without an invite)
If channel_ids is empty in trigger config, events from all channels are processed
If someone uninstalls the Slack agent from the workspace, reconnect credentials in Guild. Guild does not receive a revocation webhook.
Configure SLACK_WEBHOOK_SIGNING_SECRET for webhook verification

AI disclaimers

Because Guild agents use large language models to generate responses, they may occasionally produce inaccurate or incorrect information. Please verify any critical outputs generated by the agent. Guild does not use your Slack data, messages, or files to train large language models. All LLM operations use real-time processing and zero-copy retrieval.

Support

If you need help or have questions about the Guild Slack integration, you can contact our support team. Submit a request via our in-app chat or email support@guild.ai.

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Overview

Code & CI/CD

Communication

Project management

Testing

Productivity

Monitoring & observability

Data

Customer support

Sales & finance

Feature overview

Authentication

Setup

OAuth scopes

Usage

Selecting specific tools

API endpoints

Webhook events

How the integration works

Inbound events

Outbound API calls

Session link tracing

Link and media unfurling

Limitations

AI disclaimers

Support

Privacy policy

​Feature overview

​Authentication

​Setup

​OAuth scopes

​Usage

​Selecting specific tools

​API endpoints

​Webhook events

​How the integration works

​Inbound events

​Outbound API calls

​Session link tracing

​Link and media unfurling

​Limitations

​AI disclaimers

​Support

​Privacy policy

Feature overview

Authentication

Setup

OAuth scopes

Usage

Selecting specific tools

API endpoints

Webhook events

How the integration works

Inbound events

Outbound API calls

Session link tracing

Link and media unfurling

Limitations

AI disclaimers

Support

Privacy policy