# chat_update

A write tool on the Slack MCP server.

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

## Facts

- Tool: `chat_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": "chat_update",
    "arguments": {}
  }
}
```

## Why chat_update is rated Medium

chat_update modifies existing Slack messages, making it a Write operation (reversible data modification). Severity is medium because an AI agent could update messages to spread misinformation, impersonate users, or disrupt communication, but changes are reversible and scoped to accessible messages.

From the tool's own definition: "Tool name is 'chat_update' on Slack MCP server providing access to Slack messages and channels. The 'update' operation modifies existing chat messages."

## Use case

AI agents use chat_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": {
    "chat_update": {
      "limits": [
        {
          "counter": "chat_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