Downloads an attachment from an email. Returns file metadata and base64-encoded content.
AI agents call download-attachment to retrieve information from Outlook Assistant without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool retrieves and returns existing email attachment data without creating, modifying, deleting, or executing anything. While the downloaded content could theoretically be malicious, the tool itself performs only a read operation. The primary risk is data exposure (reading email attachments), which is inherent to the authorization model rather than the tool's action.
From the tool's definition Tool name 'download-attachment' and description state it 'Downloads an attachment from an email' and 'Returns file metadata and base64-encoded content.' This is a retrieval operation with no modification or deletion of data.
Attacks that exploit this kind of access
Downloads an attachment from an email. Returns file metadata and base64-encoded content. It is categorised as a Read tool in the Outlook Assistant MCP Server, which means it retrieves data without modifying state.
Register the Outlook Assistant 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 Outlook Assistant. 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 Outlook Assistant MCP server (titanzero/outlook-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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