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agent-slack

automate Slack messaging and workflows

Published by Letta Updated Jul 13
Covers Automation CLI Messaging Slack

Description

Slack automation CLI — read/send/search messages, browse threads and channels, manage channels, download attachments, look up users, and run workflows.

SKILL.md

Slack automation with agent-slack

agent-slack is a CLI binary on $PATH. Invoke directly (e.g. agent-slack user list).

Setup

1. Install the CLI

If agent-slack is not found on $PATH, install it:

curl -fsSL https://raw.githubusercontent.com/stablyai/agent-slack/main/install.sh | sh

Alternatives: npm i -g agent-slack (requires Node >= 22.5) or nix run github:stablyai/agent-slack.

2. Authenticate with Slack

If you have Slack Desktop installed and signed in, authentication is automatic — no setup needed. Run this to verify:

agent-slack auth test

If that fails (or you don't have Slack Desktop), try importing credentials from your browser:

# Try Chrome first, then Firefox
agent-slack auth import-chrome
agent-slack auth test

agent-slack auth import-firefox
agent-slack auth test

If neither works, you can set tokens manually via environment variables:

export SLACK_TOKEN="xoxc-..."      # browser token
export SLACK_COOKIE_D="xoxd-..."   # browser cookie
agent-slack auth test

3. Verify

Check which workspaces are configured:

agent-slack auth whoami

If you have multiple workspaces, pass --workspace "myteam" to commands to disambiguate.

Canonical workflow (given a Slack message URL)

  1. Fetch a single message (plus thread summary, if any):
agent-slack message get "https://workspace.slack.com/archives/C123/p1700000000000000"
  1. If you need the full thread:
agent-slack message list "https://workspace.slack.com/archives/C123/p1700000000000000"

Browse recent channel messages

To see what's been posted recently in a channel (channel history):

agent-slack message list "general" --limit 20
agent-slack message list "C0123ABC" --limit 10
agent-slack message list "general" --with-reaction eyes --oldest "1770165109.000000" --limit 20
agent-slack message list "general" --without-reaction dart --oldest "1770165109.000000" --limit 20

This returns the most recent messages in chronological order. Use --limit to control how many (default 25). When using --with-reaction or --without-reaction, you must also pass --oldest to bound scanning.

Attachments (snippets/images/files)

message get/list and search auto-download attachments to ~/.agent-slack/tmp/downloads/ and return metadata in message.files[] (including name and path). Failed downloads include a message.files[].error field.

Draft a message (browser editor)

Opens a Slack-like rich-text editor in the browser for composing messages with formatting toolbar (bold, italic, strikethrough, links, lists, quotes, code, code blocks). After sending, shows a "View in Slack" link.

agent-slack message draft "general"
agent-slack message draft "general" "initial text"
agent-slack message draft "https://workspace.slack.com/archives/C123/p1700000000000000"

Send, edit, delete, or react

agent-slack message send "https://workspace.slack.com/archives/C123/p1700000000000000" "I can take this."
agent-slack message send "alerts-staging" "here's the report" --attach ./report.md
agent-slack message edit "https://workspace.slack.com/archives/C123/p1700000000000000" "I can take this today."
agent-slack message delete "https://workspace.slack.com/archives/C123/p1700000000000000"

agent-slack message send "general" "Here's the plan:
- Step 1: do the thing
- Step 2: verify it worked
  - Sub-step: check logs"
agent-slack message react add "https://workspace.slack.com/archives/C123/p1700000000000000" "eyes"
agent-slack message react remove "https://workspace.slack.com/archives/C123/p1700000000000000" "eyes"

Channel mode for edit/delete requires --ts:

agent-slack message edit "general" "Updated text" --workspace "myteam" --ts "1770165109.628379"
agent-slack message delete "general" --workspace "myteam" --ts "1770165109.628379"

Attach options for message send:

  • --attach <path> upload a local file (repeatable)

List channels + create/invite users

agent-slack channel list
agent-slack channel list --user "@alice" --limit 50
agent-slack channel list --all --limit 100
agent-slack channel new --name "incident-war-room"
agent-slack channel new --name "incident-leads" --private
agent-slack channel invite --channel "incident-war-room" --users "U01AAAA,@alice,bob@example.com"
agent-slack channel invite --channel "incident-war-room" --users "partner@vendor.com" --external
agent-slack channel invite --channel "incident-war-room" --users "partner@vendor.com" --external --allow-external-user-invites

For --external, invite targets must be emails. By default, invitees are external-limited; add --allow-external-user-invites to allow them to invite other users.

Search (messages + files)

Prefer channel-scoped search for reliability:

agent-slack search all "smoke tests failed" --channel "alerts" --after 2026-01-01 --before 2026-02-01
agent-slack search messages "stably test" --user "@alice" --channel general
agent-slack search files "testing" --content-type snippet --limit 10

Multi-workspace guardrail (important)

If you have multiple workspaces configured and you use a channel name (e.g. general), pass --workspace (or set SLACK_WORKSPACE_URL) to avoid ambiguity:

agent-slack message get "general" --workspace "https://myteam.slack.com" --ts "1770165109.628379"
agent-slack message get "general" --workspace "myteam" --ts "1770165109.628379"

DM / group DM channels

Get the channel ID for a DM or group DM, useful for sending messages to a group of users:

agent-slack user dm-open @alice @bob
agent-slack user dm-open U01AAAA U02BBBB U03CCCC

Mark as read

Mark a channel, DM, or group DM as read up to a given message:

agent-slack channel mark "https://workspace.slack.com/archives/C123/p1700000000000000"
agent-slack channel mark "general" --workspace "myteam" --ts "1770165109.628379"
agent-slack channel mark "D0A04PB2QBW" --workspace "myteam" --ts "1770165109.628379"

To make a specific message appear unread, set --ts to just before it (subtract 0.000001). This moves the read cursor so that message and everything after it appear as new:

agent-slack channel mark "general" --workspace "myteam" --ts "1770165109.628378"

Workflows

Discover and run Slack workflows bookmarked in channels:

# List workflows in a channel
agent-slack workflow list "#ops"

# Preview trigger metadata (no side effects)
agent-slack workflow preview "Ft123ABC"

# Get workflow definition including form fields and steps
agent-slack workflow get "Ft123ABC"
agent-slack workflow get "Wf456DEF"

# Trip a workflow trigger
agent-slack workflow run "Ft123ABC" --channel "#ops"

Canvas + Users

agent-slack canvas get "https://workspace.slack.com/docs/T123/F456"
agent-slack user list --workspace "https://workspace.slack.com" --limit 100
agent-slack user get "@alice" --workspace "https://workspace.slack.com"

References

  • references/commands.md: full command map + all flags
  • references/targets.md: URL vs #channel targeting rules
  • references/output.md: JSON output shapes + download paths
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