Schedule and automate Slack messages with rich formatting and attachments.
Prerequisites
Slack desktop app installed, OR
Chrome browser with Slack web open
Logged into the target workspace
Instructions
Open Slack:
Desktop App:
Activate the Slack application
Verify workspace is loaded
Web Version:
Navigate to app.slack.com
Confirm logged in to correct workspace
Navigate to target channel/DM:
a. Use Quick Switcher:
Press Cmd/Ctrl + K
Type channel name or person's name
Press Enter to select
b. Verify correct destination:
Check channel name in header
Confirm you have permission to post
Compose the message:
a. Click the message input field
b. Type the message content:
Support markdown formatting:
bold with asterisks
italic with underscores
code with backticks
quotes with greater than
Add emoji with :emoji_name:
Mention users with @username
Link channels with #channel
c. For attachments:
Click the + button
Select file to upload
Add optional comment
For scheduled messages:
a. Instead of Send, click the dropdown arrow
b. Select "Schedule for later"
c. Choose date and time
d. Confirm scheduling
Send or schedule the message:
Click Send button (or press Cmd/Ctrl + Enter)
Wait for confirmation
Verify delivery:
Check message appears in channel
For scheduled: verify in "Scheduled" section
Error Handling
If channel not found, list available channels
If no permission to post, inform user
If attachment too large, suggest alternatives
If rate limited, wait and retry
Notes
Respects workspace message formatting settings
Scheduled messages can be edited before sending
For recurring messages, consider Slack Workflow Builder
Thread replies: click "Reply in thread" first
1---2name: slack-automator3description: Slack Message Automator4---5# Slack Message Automator67Schedule and automate Slack messages with rich formatting and attachments.89## Prerequisites1011- Slack desktop app installed, OR12- Chrome browser with Slack web open13- Logged into the target workspace1415## Instructions16171. Open Slack:1819 **Desktop App:**20 - Activate the Slack application21 - Verify workspace is loaded2223 **Web Version:**24 - Navigate to `app.slack.com`25 - Confirm logged in to correct workspace26272. Navigate to target channel/DM:2829 a. Use Quick Switcher:30 - Press Cmd/Ctrl + K31 - Type channel name or person's name32 - Press Enter to select3334 b. Verify correct destination:35 - Check channel name in header36 - Confirm you have permission to post37383. Compose the message:3940 a. Click the message input field4142 b. Type the message content:43 - Support markdown formatting:44 - *bold* with asterisks45 - _italic_ with underscores46 - `code` with backticks47 - > quotes with greater than48 - Add emoji with :emoji_name:49 - Mention users with @username50 - Link channels with #channel5152 c. For attachments:53 - Click the + button54 - Select file to upload55 - Add optional comment56574. For scheduled messages:5859 a. Instead of Send, click the dropdown arrow60 b. Select "Schedule for later"61 c. Choose date and time62 d. Confirm scheduling63645. Send or schedule the message:65 - Click Send button (or press Cmd/Ctrl + Enter)66 - Wait for confirmation67686. Verify delivery:69 - Check message appears in channel70 - For scheduled: verify in "Scheduled" section7172## Error Handling7374- If channel not found, list available channels75- If no permission to post, inform user76- If attachment too large, suggest alternatives77- If rate limited, wait and retry7879## Notes8081- Respects workspace message formatting settings82- Scheduled messages can be edited before sending83- For recurring messages, consider Slack Workflow Builder84- Thread replies: click "Reply in thread" first
Run npx skillmds@latest add mediar-ai/slack-automator in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.
Slack Message Automator It is listed under Integrations & APIs on SkillMD.
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