AI agents use notion_append_block_children to create or update resources in Sage MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Sage MCP environment.
This tool adds content to an existing Notion page. It is a reversible write operation (blocks can be deleted after appending). It does not delete or overwrite existing data, so it falls under Write rather than Destructive. Misuse could pollute pages with unwanted content, giving it medium severity.
From the tool's definition 'Append blocks (content) to a page' — creates/adds new content to an existing Notion page
Documented attack patterns abuse exactly the kind of access notion_append_block_children gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Sage MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for notion_append_block_children:
{
"version": "1",
"default": "deny",
"tools": {
"notion_append_block_children": {
"limits": [
{
"counter": "notion_append_block_children_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}notion_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.
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Append blocks (content) to a page. It is categorised as a Write tool in the Sage MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Sage MCP server in PolicyLayer and add a rule for notion_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 Sage MCP. Nothing to install.
notion_append_block_children is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the notion_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.
Set action: deny in the PolicyLayer policy for notion_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.
notion_append_block_children is provided by the Sage MCP server (sagemcp/sagemcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 359 Sage MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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359 Sage MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.