upload-file · Nextcloud MCP: Risk & Policy

WHAT IT DOES

What upload-file does on Nextcloud

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

WHY IT NEEDS A POLICY

Why upload-file needs a policy

Uploading a file creates or modifies data in a reversible manner—the uploaded file can be deleted, replaced, or modified later. This fits the Write category. Severity is medium because while upload operations themselves are reversible, malicious uploads could introduce malware, displace legitimate files, or consume storage quotas, but the impact is contained to the NextCloud instance and remediable through deletion…

From the tool's definition Tool name 'upload-file' and description 'Upload a file to NextCloud' indicate file creation/modification. The tool creates new file content in NextCloud storage.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

upload-file Rate-limited

upload-file 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": {
    "upload-file": {
      "limits": [
        {
          "counter": "upload-file_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 Nextcloud, so you can run agents against it safely.

FAQ

Questions about upload-file

What does the upload-file tool do? +

Upload a file to NextCloud. It is categorised as a Write tool in the Nextcloud MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on upload-file? +

Register the Nextcloud MCP server in PolicyLayer and add a rule for upload-file: 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 Nextcloud. Nothing to install.

What risk level is upload-file? +

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

Can I rate-limit upload-file? +

Yes. Add a rate_limit block to the upload-file 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 upload-file completely? +

Set action: deny in the PolicyLayer policy for upload-file. 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 upload-file? +

upload-file is provided by the Nextcloud MCP server (nextcloud-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.