upload-media · Omeka S Mcp Sample MCP: Risk & Policy

WHAT IT DOES

What upload-media does on Omeka S Mcp Sample

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

WHY IT NEEDS A POLICY

Why upload-media needs a policy

The upload-media tool creates new media resources or adds attachments to items, which is a reversible write operation. It does not execute arbitrary code, delete data, or move money. Severity is medium because unauthorized media uploads could fill storage, introduce malicious files, or pollute item metadata, but the damage is containable and reversible (files can be deleted).

From the tool's definition Tool description states 'Upload media to an item in Omeka S', which creates or modifies content in the Omeka S system. The sibling tools include create-item and list-items, confirming this is a data manipulation server.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

upload-media Rate-limited

upload-media 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-media": {
      "limits": [
        {
          "counter": "upload-media_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 Omeka S Mcp Sample, so you can run agents against it safely.

FAQ

Questions about upload-media

What does the upload-media tool do? +

Upload media to an item in Omeka S. It is categorised as a Write tool in the Omeka S Mcp Sample 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-media? +

Register the Omeka S Mcp Sample MCP server in PolicyLayer and add a rule for upload-media: 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 Omeka S Mcp Sample. Nothing to install.

What risk level is upload-media? +

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

Can I rate-limit upload-media? +

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

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

upload-media is provided by the Omeka S Mcp Sample MCP server (nakamura196/omeka-s-mcp-sample). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.