update_block_content

THE RISK

Medium Risk

Why update_block_content needs a policy

The tool modifies existing data (block content) in a reversible manner, which aligns with the Write category. While updates are generally recoverable through Notion's version history or undo features, this tool can alter user content without explicit destructive intent.

From the tool's definition Tool name contains 'update' and description states 'Update a block', indicating modification of existing content. Sibling tools show this server manages Notion content including pages, blocks, and databases.

Documented attack patterns abuse exactly the kind of access update_block_content gives an agent:

POLICY

How to control update_block_content

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 update_block_content:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "update_block_content": {
      "limits": [
        {
          "counter": "update_block_content_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

update_block_content 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.

Create a free account and register Notion API MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Notion API MCP Server tools

Destructive delete_block Delete blocks Write add_content_blocks Add content blocks with positioning support Write add_todo Add a new todo with rich features Write archive_page Archive a Notion page Write create_database Create a new database with custom schema in a parent page Write create_page Create a new page in Notion Write restore_page Restore an archived Notion page Write update_page Update a Notion page

All 17 Notion API MCP Server tools →

Write tools on other servers

M-Team MCP Server download_torrent YouTube MCP Server generate_video_title Android Forensics ADB MCP Server combine_reports 0xarchive web3_signup

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about update_block_content

What does the update_block_content tool do? +

Update a block. It is categorised as a Write tool in the Notion API 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 update_block_content? +

Register the Notion API MCP Server MCP server in PolicyLayer and add a rule for update_block_content: 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.

What risk level is update_block_content? +

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

Can I rate-limit update_block_content? +

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

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

update_block_content 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.

Enforce policy on every Notion API MCP Server tool call.

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.

CHECK YOUR STACK →