create_card_preview · Mochi MCP Server MCP: Risk & Policy

WHAT IT DOES

What create_card_preview does on Mochi MCP Server

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

WHY IT NEEDS A POLICY

Why create_card_preview needs a policy

This is a preview/read-only operation that precedes a write action. The tool generates a preview of a card that would be created but does not actually create it. The description emphasizes that the user must provide explicit confirmation before apply_create_card is invoked, making this a safe intermediate step.

From the tool's definition Tool name 'create_card_preview' and description stating it 'Preview a new card' and explicitly requiring user confirmation before the actual 'apply_create_card' call. The preview action itself does not modify data—it only shows what would be created.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_card_preview Rate-limited

create_card_preview 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_card_preview": {
      "limits": [
        {
          "counter": "create_card_preview_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 Mochi MCP Server, so you can run agents against it safely.

FAQ

Questions about create_card_preview

What does the create_card_preview tool do? +

Preview a new card. IMPORTANT: After calling this, you MUST show the preview to the user and ask for explicit confirmation before calling apply_create_card. Do NOT chain these calls automatically. It is categorised as a Write tool in the Mochi MCP Server 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_card_preview? +

Register the Mochi MCP Server MCP server in PolicyLayer and add a rule for create_card_preview: 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 Mochi MCP Server. Nothing to install.

What risk level is create_card_preview? +

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

Can I rate-limit create_card_preview? +

Yes. Add a rate_limit block to the create_card_preview 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_card_preview completely? +

Set action: deny in the PolicyLayer policy for create_card_preview. 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_card_preview? +

create_card_preview is provided by the Mochi MCP Server MCP server (nz99/mochi-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.