Send messages, react with emoji, and manage threads in Slack. Use when asked to "reply", "post", "react", "notify", or communicate in Slack.
You have three typed tools for Slack via the slack MCP server:
| Tool | Purpose | Required params |
|---|---|---|
mcp__slack__slack_reply | Post a message in a channel/thread | text |
mcp__slack__slack_react | Add an emoji reaction | emoji, timestamp |
mcp__slack__slack_upload_file | Upload a local file (image, PDF, etc.) to a thread | file_path, channel |
*bold*, _italic_, ~strike~, `code`, ```code block```, <url|label> for links.**double bold**, [text](url) links, or # headings. The gateway converts these automatically, but prefer native Slack formatting.•) for lists.slack_upload_file to post the actual file. Do not just describe it — upload it. Call slack_upload_file immediately after saving the file, before replying with text.:eyes: (seen), :hourglass_flowing_sand: (working), :white_check_mark: (done).slack_reply, return [SILENT] as your final response so the gateway does not double-post your message.