# chat_post_ephemeral A write tool on the Slack MCP server. Agent View of the PolicyLayer registry record for `chat_post_ephemeral`. HTML page: https://policylayer.com/tools/karbassi-slack-mcp/chat-post-ephemeral ## Facts - Tool: `chat_post_ephemeral` - 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_post_ephemeral", "arguments": {} } } ``` ## Why chat_post_ephemeral is rated Medium Posting ephemeral (temporary) messages to Slack channels or users modifies communication state and creates new data artifacts, fitting the Write category. Severity is medium because ephemeral messages are temporary and limited in scope, though misuse could spam users or leak sensitive information to unintended recipients. From the tool's own definition: "Tool name 'chat_post_ephemeral' indicates posting messages to Slack; 'ephemeral' suggests temporary messages visible only to specific users. The server description confirms it provides 'full access to Slack: messages' via 220 tools." ## Use case AI agents use chat_post_ephemeral 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_post_ephemeral": { "limits": [ { "counter": "chat_post_ephemeral_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