upload_image · Mattcoatsworth Canva MCP: Risk & Policy

WHAT IT DOES

What upload_image does on Mattcoatsworth Canva

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

WHY IT NEEDS A POLICY

Why upload_image needs a policy

Upload operations create or add new media assets, which is reversible (images can be deleted). This qualifies as Write rather than Read. Severity is medium because unauthorized image uploads could pollute design assets or consume storage, but the blast radius is limited to media management—not destructive deletion, financial impact, or arbitrary code execution.

From the tool's definition Tool name 'upload_image' indicates file/media creation. Description is empty, limiting specificity. Context: sibling tools are read-only (get_*, list_*), making this a write operation on a Canva API server.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

upload_image Rate-limited

upload_image 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_image": {
      "limits": [
        {
          "counter": "upload_image_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 Mattcoatsworth Canva, so you can run agents against it safely.

FAQ

Questions about upload_image

What does the upload_image tool do? +

upload_image. It is categorised as a Write tool in the Mattcoatsworth Canva 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_image? +

Register the Mattcoatsworth Canva MCP server in PolicyLayer and add a rule for upload_image: 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 Mattcoatsworth Canva. Nothing to install.

What risk level is upload_image? +

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

Can I rate-limit upload_image? +

Yes. Add a rate_limit block to the upload_image 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_image completely? +

Set action: deny in the PolicyLayer policy for upload_image. 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_image? +

upload_image is provided by the Mattcoatsworth Canva MCP server (@iflow-mcp/mattcoatsworth-canva-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.