append_block_children · Notion MCP Server MCP: Risk & Policy

WHAT IT DOES

What append_block_children does on Notion MCP Server

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

WHY IT NEEDS A POLICY

Why append_block_children needs a policy

This tool adds new child blocks to an existing Notion block, which is a reversible write operation. It creates/modifies content but does not delete or overwrite existing data, so it falls under Write rather than Destructive. Misuse could clutter or corrupt page structure but is generally recoverable.

From the tool's definition Append children to a Notion block

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

append_block_children Rate-limited

append_block_children 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_block_children": {
      "limits": [
        {
          "counter": "append_block_children_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 MCP Server, so you can run agents against it safely.

FAQ

Questions about append_block_children

What does the append_block_children tool do? +

Append children to a Notion block. It is categorised as a Write tool in the Notion 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_block_children? +

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

What risk level is append_block_children? +

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

Can I rate-limit append_block_children? +

Yes. Add a rate_limit block to the append_block_children 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_block_children completely? +

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

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

// THE FULL RECORD

append_block_children is one line of Notion MCP Server's registry record.

The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.

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