# usergroups_users_update

A write tool on the Slack MCP server.

Agent View of the PolicyLayer registry record for `usergroups_users_update`. HTML page: https://policylayer.com/tools/karbassi-slack-mcp/usergroups-users-update

## Facts

- Tool: `usergroups_users_update`
- Server: Slack (`karbassi/slack-mcp`) — https://policylayer.com/tools/karbassi-slack-mcp.md
- Homepage: https://github.com/karbassi/slack-mcp
- Risk category: Write (Medium risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "usergroups_users_update",
    "arguments": {}
  }
}
```

## Why usergroups_users_update is rated Medium

The tool performs a reversible modification action (updating user group memberships) rather than deletion or execution of arbitrary code. This qualifies as Write category. Severity is high because modifying user group memberships can affect access controls, permissions, and organizational structure in Slack, with potential impact on collaboration and security boundaries.

From the tool's own definition: "Tool name 'usergroups_users_update' indicates modification of user group membership. The verb 'update' combined with 'usergroups_users' strongly suggests writing/modifying group membership data. Description is empty, reducing confidence slightly."

## Use case

AI agents use usergroups_users_update to create or update resources in Slack, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Slack environment.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Slack:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "usergroups_users_update": {
      "limits": [
        {
          "counter": "usergroups_users_update_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Slack (232)

- `apps_manifest_delete` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/apps-manifest-delete.md
- `apps_uninstall` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/apps-uninstall.md
- `auth_revoke` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/auth-revoke.md
- `bookmarks_remove` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/bookmarks-remove.md
- `cache_clear` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/cache-clear.md
- `calls_participants_remove` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/calls-participants-remove.md
- `canvases_access_delete` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/canvases-access-delete.md
- `canvases_delete` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/canvases-delete.md
- `channels_delete` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/channels-delete.md
- `chat_delete` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/chat-delete.md
- `chat_delete_scheduled_message` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/chat-delete-scheduled-message.md
- `conversations_kick` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/conversations-kick.md
- `drafts_delete` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/drafts-delete.md
- `emoji_remove` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/emoji-remove.md
- `files_comments_delete` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/files-comments-delete.md
- `files_delete` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/files-delete.md
- `files_remote_remove` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/files-remote-remove.md
- `files_revoke_public_url` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/files-revoke-public-url.md
- `pins_remove` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/pins-remove.md
- `reactions_remove` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/reactions-remove.md
- `reminders_delete` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/reminders-delete.md
- `saved_delete` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/saved-delete.md
- `slack_lists_access_delete` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/slack-lists-access-delete.md
- `slack_lists_items_delete` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/slack-lists-items-delete.md
- `slack_lists_items_delete_multiple` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/slack-lists-items-delete-multiple.md
- `stars_remove` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/stars-remove.md
- `team_external_teams_disconnect` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/team-external-teams-disconnect.md
- `users_admin_set_inactive` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/users-admin-set-inactive.md
- `users_delete_photo` — Destructive — https://policylayer.com/tools/karbassi-slack-mcp/users-delete-photo.md
- `apps_connections_open` — Execute — https://policylayer.com/tools/karbassi-slack-mcp/apps-connections-open.md
- …and 202 more: https://policylayer.com/tools/karbassi-slack-mcp.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=karbassi-slack-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/karbassi-slack-mcp