send-slack-message

name	send-slack-message
description	Send a message to a Slack channel with markdown support, colored attachments, and deduplication. Use when the user wants to post notifications or alerts to Slack.
argument-hint	[channel] [message-text]
allowed-tools	Bash(node *)

Send Slack Message

Send a markdown or plain-text message to a Slack channel.

Usage

Run from the project root:

# Simple text message
node run.js ./src/sendSlackMessage.js --channel="#secops-hotspots" --text="Hello world"

# Markdown body message
node run.js ./src/sendSlackMessage.js --channel="#secops-hotspots" --message="**Bold** message"

# With color (named or hex)
node run.js ./src/sendSlackMessage.js --channel="#secops-hotspots" --message="Alert!" --color=red

# With custom bot username
node run.js ./src/sendSlackMessage.js --channel="#secops-hotspots" --text="Hello" --username=security-bot

Parameters

Parameter	Required	Default	Description
--token	No	$SLACK_TOKEN	Slack bot token (xoxb-...). Falls back to env var
--channel	Yes	-	Slack channel name (e.g. #secops-hotspots)
--text	No*	-	Plain text / mrkdwn summary line
--message	No*	-	Markdown body (converted to Slack Block Kit)
--color	No	-	Named color (red, green, yellow, blue, cyan, magenta, black, white) or hex (#FF5733)
--username	No	github-actions	Bot display name
--debug	No	false	Enable debug logging

* At least one of --text or --message is required. Both can be provided.

Output

Returns the Slack API response JSON including ok status, message timestamp (ts), and channel ID.

Prerequisites

• .env file with SLACK_TOKEN (bot token with chat:write, channels:read, channels:history scopes)
• The bot must be invited to the target channel

Notes

• The run.js entry point automatically loads .env credentials
• Markdown is converted to Slack Block Kit format via @tryfabric/mack
• Messages are deduplicated: the same (text + message + color) combination won't be posted twice within 24 hours
• Slack blocks are capped at 50 (Slack API limit); longer messages are truncated
• This is a write operation -- confirm with the user before sending if the message wasn't explicitly provided