Slack

Overview

The Slack integration is intake-first: its primary job is pulling your team’s Slack conversation into the project, not broadcasting out of it. mm_slack_ingest captures channel messages and thread context into a per-project inbox, where items surface in daily briefs and the desktop app’s comms inbox and can be shaped into issues and specs. Outbound posting — status updates and activity digests — is the secondary lane.

Tool Group

All three Slack tools belong to the opt-in slack tool group. They are not listed in the agent’s tool catalog until you opt in via the Monday Morning server entry in .mcp.json:

"env": { "MM_TOOL_GROUPS": "slack" }

The tools still dispatch by name even when not listed — opting in only makes them visible in tools/list.

Prerequisites

A Slack workspace where you have permission to install apps
A Slack app with a bot/user OAuth token
The bot must be invited to the channels it reads from or posts to

Setup

The desktop app offers two paths: an OAuth flow (Connect with Slack), or pasting a token manually.

Path A: Connect with Slack (OAuth)

Create an app at api.slack.com/apps and copy its Client ID and Client Secret from Basic Information → App Credentials
In Monday Morning, open the Slack plugin’s settings (Settings → Plugins, Configure on the Slack row), enter the Client ID and Client Secret, and click Connect with Slack
Authorize in the browser — the token is stored for you

Path B: Manual token

Go to api.slack.com/apps → Create New App → From scratch
Under OAuth & Permissions, add these scopes:
- channels:read and channels:history — list and read public channels
- groups:read and groups:history — list and read private channels
- users:read — resolve message authors
- chat:write — post messages
Click Install to Workspace and copy the OAuth token
Paste it into the token field in the Slack plugin’s settings

Either way, the desktop app writes the token to the bridge file .mm/integrations/slack.json, which is what the MCP tools read — there is no environment-variable fallback for Slack.

Invite the bot to channels

/invite @Monday Morning

Invite it to the channel you ingest from and any channel it posts to.

Per-project settings

The Slack plugin’s per-project settings (rendered in the plugin’s Configure form) control routing and cadence:

Setting	Description	Default
`default_channel`	Fallback channel for posts and ingestion	—
`ingest_channel`	Channel to ingest team messages from (falls back to `default_channel`)	—
`ingest_frequency`	Automatic ingestion: `off`, `daily`, or `weekly`	`off`
`digest_frequency`	Automatic digests: `off`, `daily`, or `weekly`	`off`
`digest_time`	Time of day for automatic digests	`17:00`
`post_on_pr_merge`	Auto-post a plain-language update when a PR merges to the default branch (requires a GitHub repo configured)	`false`
`pr_merge_channel`	Channel for PR-merge updates (falls back to `default_channel`)	—

Verify the connection

Ingest recent messages from our Slack channel

The agent will call mm_slack_ingest. If configured correctly, it reports how many messages were scanned and how many new inbox items were captured.

Available Tools

Tool	Description
`mm_slack_ingest`	Ingest messages from a Slack channel (excluding bot messages) into the project inbox. Captures messages and thread context for review, triage, and spec shaping.
`mm_slack_post_update`	Post a formatted message to a Slack channel. Supports Slack mrkdwn formatting.
`mm_slack_digest`	Generate and post a `daily` or `weekly` activity digest — completed tasks, spec progress, and commit counts.

mm_slack_ingest in detail

Parameters:

project_path (required) — absolute path to the project root
channel (optional) — channel to ingest from; falls back to ingest_channel, then default_channel
lookback_hours (optional) — how many hours back to fetch messages (default: 24)

Behavior: it fetches channel history and thread replies for the lookback window, skips bot messages, and merges the results into .mm/plugins/slack/inbox.json — deduplicating against items already captured and pruning old dismissed/converted entries. Items are tagged with source: "slack" and surfaced in daily briefs. The result reports new_items, total_inbox, messages_scanned, and threads_fetched.

Common Workflows

Triage the team channel

Ingest the last two days of #project-chat and summarize anything that needs a decision

The agent calls mm_slack_ingest with lookback_hours: 48, then reads the new inbox items back to you. From the desktop app, the same items appear in the comms inbox for conversion into issues or specs.

Post a project status update

Post a Slack update to #engineering summarizing what was completed today

The agent gathers recent activity and calls mm_slack_post_update with a formatted summary.

Send a weekly digest

Send a weekly activity digest to the #project-updates channel

The agent calls mm_slack_digest with period: "weekly", which compiles task completions, spec progress, and commit counts into a formatted Slack message.

Troubleshooting

“Slack bot token not found” error Open the desktop app, go to Settings → Plugins → Slack, and add your token. It is written to .mm/integrations/slack.json for MCP access.

“not_in_channel” error The bot has not been invited to the target channel. Run /invite @Monday Morning in that channel.

“invalid_auth” error Your token is invalid or the app has been uninstalled. Reconnect with Slack or generate a new token at api.slack.com/apps.

“No channel specified” error Pass a channel parameter, or set ingest_channel / default_channel in the Slack plugin’s per-project settings.

The agent says it can’t see the Slack tools The slack group is not opted in. Add "MM_TOOL_GROUPS": "slack" to the server’s env in .mcp.json — or ask the agent to call the tool by its exact name; delisted tools still dispatch.

Private channel not readable Private channels require the groups:read and groups:history scopes, and the bot must be a member.