Registers a new Call.

An MCP tool from the Slack API server, hosted on mcp.hjlabs.in.

Registers a new Call. [POST /calls.add]

Name on the gateway: slack_api__calls_add · may change things.

Parameters

Name	Type	Description
`external_unique_id` required	`string`	An ID supplied by the 3rd-party Call provider. It must be unique across all…
`external_display_id`	`string`	An optional, human-readable ID supplied by the 3rd-party Call provider. If…
`join_url` required	`string`	The URL required for a client to join the Call.
`desktop_app_join_url`	`string`	When supplied, available Slack clients will attempt to directly launch the…
`date_start`	`integer`	Call start time in UTC UNIX timestamp format
`title`	`string`	The name of the Call.
`created_by`	`string`	The valid Slack user ID of the user who created this Call. When this method is…
`users`	`string`	The list of users to register as participants in the Call. Read more on how to…

Through the Smart Gateway, any client can run it by name with call_tool, or let the gateway find it with search_tools:

call_tool arguments

{
  "name": "slack_api__calls_add",
  "arguments": {
    "external_unique_id": "…",
    "join_url": "…"
  }
}

Or connect the Slack API server directly, which lists 174 tools including this one:

Run in your terminal

claude mcp add --transport http hj-slack-api https://mcp.hjlabs.in/mcp/slack-api \
  --header "Authorization: Bearer YOUR_API_KEY"

Use the registers a new call. tool with external_unique_id set to ….