AI agents call list_block_children to retrieve information from Notion API MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool retrieves hierarchical block information from Notion, which is a read-only query operation. It has no capacity to modify, delete, or execute operations. The context of sibling tools (create_page, delete_block, archive_page) that perform writes/deletions makes it clear this tool is purely for data retrieval. Risk is low as misuse would only expose existing data structure.
From the tool's definition Tool name 'list_block_children' and description 'List all children of a block' indicate a retrieval/query operation with no data modification. This aligns with the Read category pattern of listing and fetching data without side effects.
Documented attack patterns abuse exactly the kind of access list_block_children gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Notion API MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for list_block_children:
{
"version": "1",
"default": "deny",
"tools": {
"list_block_children": {}
}
}list_block_children is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List all children of a block. It is categorised as a Read tool in the Notion API MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Notion API MCP Server MCP server in PolicyLayer and add a rule for list_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 API MCP Server. Nothing to install.
list_block_children is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the list_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.
Set action: deny in the PolicyLayer policy for list_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.
list_block_children is provided by the Notion API MCP Server MCP server (pbohannon/notion-api-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Notion API MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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17 Notion API MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.