| name | slack-msg |
| version | 1.0.0 |
| description | Post messages, list channels, and reply to threads via the Slack Web API. |
| author | ZeptoClaw |
| license | MIT |
| tags | ["slack","messaging","communication","notifications"] |
| env_needed | [{"name":"SLACK_BOT_TOKEN","description":"Bot token (xoxb-) from api.slack.com/apps","required":true}] |
| metadata | {"zeptoclaw":{"emoji":"💬","requires":{"anyBins":["curl","jq"]}}} |
Slack Message Skill
Post messages, list channels, and reply to threads using the Slack Web API.
Setup
- Go to api.slack.com/apps → Create New App
- Add Bot Token Scopes:
chat:write, channels:read, files:write
- Install app to workspace → Copy Bot User OAuth Token
export SLACK_BOT_TOKEN="xoxb-xxx..."
Post a Message
curl -s -X POST "https://slack.com/api/chat.postMessage" \
-H "Authorization: Bearer $SLACK_BOT_TOKEN" \
-H "Content-Type: application/json" \
-d '{
"channel": "C0XXXXXX",
"text": "Deploy completed successfully"
}' | jq '{ok, ts: .ts, channel: .channel}'
List Channels
curl -s "https://slack.com/api/conversations.list?types=public_channel&limit=50" \
-H "Authorization: Bearer $SLACK_BOT_TOKEN" \
| jq '.channels[] | {id, name, num_members}'
Reply to a Thread
curl -s -X POST "https://slack.com/api/chat.postMessage" \
-H "Authorization: Bearer $SLACK_BOT_TOKEN" \
-H "Content-Type: application/json" \
-d '{
"channel": "C0XXXXXX",
"thread_ts": "1234567890.123456",
"text": "Thread reply from agent"
}' | jq '{ok, ts}'
Post with Blocks (Rich Formatting)
curl -s -X POST "https://slack.com/api/chat.postMessage" \
-H "Authorization: Bearer $SLACK_BOT_TOKEN" \
-H "Content-Type: application/json" \
-d '{
"channel": "C0XXXXXX",
"blocks": [
{"type": "header", "text": {"type": "plain_text", "text": "Daily Report"}},
{"type": "section", "text": {"type": "mrkdwn", "text": "*Errors:* 3\n*Uptime:* 99.9%"}}
]
}' | jq '{ok, ts}'
Tips
- Channel IDs start with
C (public) or G (private) — use IDs not names
- Bot must be invited to a channel before posting:
/invite @botname
- Rate limit: ~1 message/second per channel (burst: 100 per minute)
thread_ts is the timestamp of the parent message- Slack uses
mrkdwn (not markdown) — bold is *text*, italic is _text_
