Download a file from a remote host (over SFTP, reusing the persistent SSH pool) to the local filesystem where this MCP server is running. Streams the transfer — file size is not RAM-bound. Use this when working from Claude.ai web (the cloud sandbox has no access to the local disk) or when scp/rsy...
AI agents call sftp_download to retrieve information from Self-hosted MCP server for Claude without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The sftp_download tool retrieves files from a remote system to local storage. While this is fundamentally a read operation (no data is modified or destroyed), the severity is elevated to medium because: (1) it can exfiltrate sensitive data from remote systems if an agent is compromised or misused, (2) the tool operates over SSH with persistent connections, expanding blast radius, and (3) context indicates access to…
From the tool's definition Tool description states it 'Download[s] a file from a remote host...to the local filesystem' — a retrieval operation with no modification or deletion of source data.
Attacks that exploit this kind of access
Download a file from a remote host (over SFTP, reusing the persistent SSH pool) to the local filesystem where this MCP server is running. Streams the transfer — file size is not RAM-bound. Use this when working from Claude.ai web (the cloud sandbox has no access to the local disk) or when scp/rsync isn. It is categorised as a Read tool in the Self-hosted MCP server for Claude MCP Server, which means it retrieves data without modifying state.
Register the Self-hosted MCP server for Claude MCP server in PolicyLayer and add a rule for sftp_download: 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 Self-hosted MCP server for Claude. Nothing to install.
sftp_download 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 sftp_download 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 sftp_download. 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.
sftp_download is provided by the Self-hosted MCP server for Claude MCP server (leszczynskikarol/mcp-server). 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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