Slack Plugin

Plugin ID: slack | Auth: OAuth2 (provider id slack) | Scopes: channels:read, chat:write, groups:read Handlers call Slack’s Web API at https://slack.com/api/<method>. List uses conversations.list with types=public_channel,private_channel and exclude_archived=true; post uses chat.postMessage and respects thread_ts when supplied. The destructive messages.post tool elicits user approval before sending — denied approvals throw before any API call is made.

Tools

slack.channels.list

Name: List Channels List Slack channels accessible to the bot.

Parameter	Type	Required	Default	Description
`limit`	`integer`	No	`50`	Max channels to return

Output:

{
  "channels": [
    {
      "id": "C01ABC23DEF",
      "name": "engineering",
      "topic": "Engineering discussions",
      "memberCount": 42
    }
  ]
}

slack.messages.post

Name: Post Message | Destructive: No Post a new message to a Slack channel via chat.postMessage. Additive write — creates new content; does not delete or overwrite existing data. The MCP host presents the tool call to the user for approval before invoking.

Parameter	Type	Required	Description
`channel`	`string`	Yes	Channel ID (e.g. `C0123456789`, preferred) or channel name with leading `#` (e.g. `#general`). Bare names without `#` are rejected by Slack with `channel_not_found`.
`text`	`string`	Yes	Message body. Must be non-empty (Slack returns `no_text` otherwise).
`threadTs`	`string`	No	Parent message `ts` to reply in-thread.

Output:

{
  "ts": "1705312800.000100",
  "channel": "C01ABC23DEF"
}

Getting Started

Guides

Plugins

Tools

slack.channels.list

slack.messages.post

​Tools

​slack.channels.list

​slack.messages.post

Tools

slack.channels.list

slack.messages.post