plone_add_single_block · Plone MCP Server MCP: Risk & Policy

WHAT IT DOES

What plone_add_single_block does on Plone MCP Server

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

WHY IT NEEDS A POLICY

Why plone_add_single_block needs a policy

The tool creates new blocks within existing content items. This is a Write operation because it creates or modifies data reversibly—blocks can be modified or removed later. It's not Destructive (no irreversible deletion), not Execute (no arbitrary code execution or external operations triggered), and not Financial.

From the tool's definition Tool name contains 'add' and description states 'Adds a single new block to an existing content item'. This is a create/insert operation that modifies content reversibly.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

plone_add_single_block Rate-limited

plone_add_single_block 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": {
    "plone_add_single_block": {
      "limits": [
        {
          "counter": "plone_add_single_block_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 Plone MCP Server, so you can run agents against it safely.

FAQ

Questions about plone_add_single_block

What does the plone_add_single_block tool do? +

Adds a single new block to an existing content item without replacing other blocks. Specify the block type, data, and optional position. Example: plone_add_single_block({path:. It is categorised as a Write tool in the Plone 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 plone_add_single_block? +

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

What risk level is plone_add_single_block? +

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

Can I rate-limit plone_add_single_block? +

Yes. Add a rate_limit block to the plone_add_single_block 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 plone_add_single_block completely? +

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

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