create-share · Nextcloud MCP: Risk & Policy

WHAT IT DOES

What create-share does on Nextcloud

AI agents use create-share 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 create-share needs a policy

Creating a share link is a write operation—it generates and persists a new sharing configuration that changes who can access a resource. It is reversible via delete-share (a sibling tool), so it does not rise to Destructive.

From the tool's definition Tool creates a share link, which is a new resource/configuration ("Create a share"). This modifies the access state of a file or directory by establishing a new sharing relationship.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create-share Rate-limited

create-share 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": {
    "create-share": {
      "limits": [
        {
          "counter": "create-share_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 create-share

What does the create-share tool do? +

Create a share link for a file or directory. 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 create-share? +

Register the Nextcloud MCP server in PolicyLayer and add a rule for create-share: 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 create-share? +

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

Can I rate-limit create-share? +

Yes. Add a rate_limit block to the create-share 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 create-share completely? +

Set action: deny in the PolicyLayer policy for create-share. 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 create-share? +

create-share 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.