Revoke public/external sharing access for a file.
AI agents call files_revoke_public_url to permanently remove resources in Slack — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Revoking public URL access is an irreversible action that removes external sharing capabilities for a file. Once revoked, any external links to the file will stop working, and previously shared access cannot be automatically restored. This constitutes a destructive operation with potentially high impact if an AI agent misuses it on files that were intentionally shared publicly.
From the tool's definition Revoke public/external sharing access for a file
Attacks that exploit this kind of access
Revoke public/external sharing access for a file. It is categorised as a Destructive tool in the Slack MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Slack MCP server in PolicyLayer and add a rule for files_revoke_public_url: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Slack. Nothing to install.
files_revoke_public_url is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the files_revoke_public_url rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for files_revoke_public_url. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
files_revoke_public_url is provided by the Slack MCP server (karbassi/slack-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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