# canvases_edit

Edit a canvas.

Agent View of the PolicyLayer registry record for `canvases_edit`. HTML page: https://policylayer.com/tools/karbassi-slack-mcp/canvases-edit

## Facts

- Tool: `canvases_edit`
- 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": "canvases_edit",
    "arguments": {}
  }
}
```

## Why canvases_edit is rated Medium

This tool creates or modifies canvas data in Slack, which is reversible (can be edited again or reverted). It does not delete data (would be Destructive) or execute arbitrary code (would be Execute), but it does allow an AI agent to alter shared workspace content that other users may depend on. High severity due to potential for unintended modifications to collaborative documents that could impact team workflows.

From the tool's own definition: "Tool name 'canvases_edit' and description 'Edit a canvas' indicate modification of existing data. The Slack API documentation confirms canvases.edit modifies canvas content, making this a reversible write operation."

## Use case

AI agents use canvases_edit 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": {
    "canvases_edit": {
      "limits": [
        {
          "counter": "canvases_edit_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`

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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
