download_attachment
AI agents call download_attachment to retrieve information from Zimbra MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Downloading an attachment retrieves existing data without modifying, deleting, or executing external operations. Despite the empty description lowering confidence slightly, the name and server context (email management tools) indicate this performs a read operation to fetch attachment content. Attachment download is a standard, side-effect-free retrieval action.
From the tool's definition Tool name is 'download_attachment' with empty description; context indicates this is part of an email management system (Zimbra MCP Server) focused on email, calendar, and contact operations. Download/retrieval operations are non-destructive data access.
Attacks that exploit this kind of access
download_attachment. It is categorised as a Read tool in the Zimbra MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Zimbra MCP Server MCP server in PolicyLayer and add a rule for download_attachment: 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 Zimbra MCP Server. Nothing to install.
download_attachment is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the download_attachment 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 download_attachment. 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.
download_attachment is provided by the Zimbra MCP Server MCP server (jeremie-lesage/zimbra-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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