Clear cached attachment files to free disk space. - Provide itemKey to clear cache for a specific attachment - Omit itemKey to clear all cached attachments
AI agents call clear_attachment_cache to permanently remove resources in Zotero — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Although the data being cleared is technically 'cache' (secondary copies), this operation irreversibly deletes files from disk. In the context of a Zotero reference manager, cached attachments represent local working copies that users depend on.
From the tool's definition The tool description states 'Clear cached attachment files to free disk space' with the ability to clear 'all cached attachments' when itemKey is omitted. This irreversibly removes cached data without a straightforward recovery mechanism.
Attacks that exploit this kind of access
Clear cached attachment files to free disk space. - Provide itemKey to clear cache for a specific attachment - Omit itemKey to clear all cached attachments. It is categorised as a Destructive tool in the Zotero MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Zotero MCP server in PolicyLayer and add a rule for clear_attachment_cache: 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 Zotero. Nothing to install.
clear_attachment_cache 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 clear_attachment_cache 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 clear_attachment_cache. 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.
clear_attachment_cache is provided by the Zotero MCP server (xbghc/zotero-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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