ssh_upload · Claude Ssh MCP: Risk & Policy

WHAT IT DOES

What ssh_upload does on Claude Ssh

AI agents use ssh_upload to create or update resources in Claude Ssh — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Claude Ssh environment.

WHY IT NEEDS A POLICY

Why ssh_upload needs a policy

This tool transfers a file from local to remote, creating or overwriting content on the remote server. It is a Write operation by default, but carries high severity because it could overwrite critical files on remote systems.

From the tool's definition Upload a local file to a remote server via SFTP

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

ssh_upload Rate-limited

ssh_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": {
    "ssh_upload": {
      "limits": [
        {
          "counter": "ssh_upload_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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

FAQ

Questions about ssh_upload

What does the ssh_upload tool do? +

Upload a local file to a remote server via SFTP. It is categorised as a Write tool in the Claude Ssh MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on ssh_upload? +

Register the Claude Ssh MCP server in PolicyLayer and add a rule for ssh_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 Claude Ssh. Nothing to install.

What risk level is ssh_upload? +

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

Can I rate-limit ssh_upload? +

Yes. Add a rate_limit block to the ssh_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 ssh_upload completely? +

Set action: deny in the PolicyLayer policy for ssh_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 ssh_upload? +

ssh_upload is provided by the Claude Ssh MCP server (marabank/mcp-ssh-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.