Slack automation with `agent-slack` Skill

Slack automation with `agent-slack`

agent-slack is a CLI binary installed on $PATH. Invoke it directly (e.g. agent-slack user list). If installed via Nix flake only, run commands with nix run github:stablyai/agent-slack -- <args>.

Quick start (auth)

Authentication is automatic on macOS and Windows (Slack Desktop first, then Chrome/Firefox fallbacks on macOS).

If credentials aren’t available, run one of:

Slack Desktop import (macOS/Windows):

agent-slack auth import-desktop
agent-slack auth test

Chrome fallback:

agent-slack auth import-chrome
agent-slack auth test

Firefox fallback:

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

Or set env vars (browser tokens; avoid pasting these into chat logs):

export SLACK_TOKEN="xoxc-..."
export SLACK_COOKIE_D="xoxd-..."
agent-slack auth test

Or set a standard token:

export SLACK_TOKEN="xoxb-..."  # or xoxp-...
agent-slack auth test

Check configured workspaces:

agent-slack auth whoami

Canonical workflow (given a Slack message URL)

Fetch a single message (plus thread summary, if any):

agent-slack message get "https://workspace.slack.com/archives/C123/p1700000000000000"

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 and include absolute paths in JSON output (typically under message.files[].path / files[].path).

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"

# Bullet lists are auto-detected and rendered as native Slack rich text:
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 (#general / 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

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

Agent Skills: Slack automation with `agent-slack`

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