sftp_upload · Self-hosted MCP server for Claude MCP

WHAT IT DOES

What sftp_upload does on Self-hosted MCP server for Claude

AI agents use sftp_upload to create or update resources in Self-hosted MCP server for Claude — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Self-hosted MCP server for Claude environment.

WHY IT NEEDS A POLICY

Why sftp_upload needs a policy

This tool uploads files to remote hosts, which is a Write operation—it creates or modifies data reversibly on remote systems. Severity is high because an AI agent with write access to remote hosts could overwrite critical configuration files, application binaries, or credentials, leading to service disruption or compromise.

From the tool's definition Tool name is 'sftp_upload' with description 'Upload a local file to a remote host (over SFTP...)'. It creates or modifies data on a remote system by transferring a file.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

sftp_upload Rate-limited

sftp_upload stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "sftp_upload": {
      "limits": [
        {
          "counter": "sftp_upload_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Self-hosted MCP server for Claude, so you can run agents against it safely.

FAQ

Questions about sftp_upload

What does the sftp_upload tool do? +

Upload a local file to a remote host (over SFTP, reusing the persistent SSH pool). Streams the transfer. Use when scp/rsync isn. It is categorised as a Write tool in the Self-hosted MCP server for Claude MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on sftp_upload? +

Register the Self-hosted MCP server for Claude MCP server in PolicyLayer and add a rule for sftp_upload: 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.

What risk level is sftp_upload? +

sftp_upload is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit sftp_upload? +

Yes. Add a rate_limit block to the sftp_upload 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.

How do I block sftp_upload completely? +

Set action: deny in the PolicyLayer policy for sftp_upload. 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.

What MCP server provides sftp_upload? +

sftp_upload 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.