append_blocks · Notion Direct MCP Server MCP: Risk & Policy

WHAT IT DOES

What append_blocks does on Notion Direct MCP Server

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

WHY IT NEEDS A POLICY

Why append_blocks needs a policy

Appending blocks creates new content within Notion pages or blocks. This is a reversible write operation (blocks can be deleted afterward), making it a Write category. Misuse could add unwanted content to important pages, hence medium severity.

From the tool's definition 'Append blocks to a page or block' — adds new content to an existing page or block

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

append_blocks Rate-limited

append_blocks 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": {
    "append_blocks": {
      "limits": [
        {
          "counter": "append_blocks_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 Notion Direct MCP Server, so you can run agents against it safely.

FAQ

Questions about append_blocks

What does the append_blocks tool do? +

Append blocks to a page or block. It is categorised as a Write tool in the Notion Direct 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 append_blocks? +

Register the Notion Direct MCP Server MCP server in PolicyLayer and add a rule for append_blocks: 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 Notion Direct MCP Server. Nothing to install.

What risk level is append_blocks? +

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

Can I rate-limit append_blocks? +

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

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

append_blocks is provided by the Notion Direct MCP Server MCP server (wayy-research/notion-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.