Slack MCP connector #

Open /mcp (or /plugins), search for Slack, and connect. You can also run /mcp login slack inside Prime Agent. Complete Slack's consent screen in your browser. The connection becomes available to the current session through the generic mcp Python API:

tools = await mcp.list_tools("slack")
# Read the returned inputSchema before calling a tool.

Prime Agent connects to Slack's hosted Streamable HTTP server at https://mcp.slack.com/mcp. It uses the public desktop OAuth client published in Slack's agent harness guide: client ID 1601185624273.8899143856786 and callback http://localhost:3118/callback. This is the client used by Slack's Claude Code plugin, so Slack's consent screen may identify the app as Claude. Prime Agent uses PKCE and state validation, then stores the grant in its own auth store; no Claude installation or credentials are needed.

Slack does not offer dynamic client registration. Workspace administrators still control app approval and granted scopes. The desktop client registration is controlled by Slack and its partner; changes there can require an update.

If port 3118 is occupied, finish or close the other login attempt and retry. Prime Agent reports the conflict instead of redirecting to an unregistered port. For SSH sessions, forward local port 3118 to port 3118 on the host running Prime Agent, or paste the final redirect URL into the auth panel.

Disconnect with /mcp logout slack. Connector usage contributes to the existing mcp_connector_use_count session telemetry counter; server names and Slack content are not recorded in that counter.