roam_create_block

THE RISK

Medium Risk

Why roam_create_block needs a policy

This tool creates new blocks within a Roam graph, which is a Write operation—it modifies data reversibly without destructive or financial implications. Severity is medium because uncontrolled block creation could spam a user's graph with unwanted content, but the impact is limited to that single graph and reversible. The confidence is high given the clear description of the tool's function.

From the tool's definition Tool creates new content blocks in Roam Research: 'Add a new block to an existing Roam page'. The action is reversible (blocks can be deleted) but modifies user data.

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

POLICY

How to control roam_create_block

PolicyLayer is an MCP gateway — it sits between your AI agents and Roam Research MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for roam_create_block:

policy.json

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

roam_create_block 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 Roam Research 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 Roam Research MCP Server tools

Destructive roam_delete_block Delete a single block from the graph by its UID. Destructive roam_delete_page Delete a page and all of its blocks from the graph by its UID. Execute roam_datomic_query Execute a custom Datomic query on the Roam graph beyond the available search tools. Write roam_add_todo Add a list of todo items as individual blocks to today's daily page in Roam. Write roam_create_outline roam_create_outline Write roam_create_page roam_create_page Write roam_import_markdown roam_import_markdown Write roam_remember Add a memory or piece of information to remember, stored on the daily page with tag.

All 26 Roam Research MCP Server tools →

Write tools on other servers

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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 roam_create_block

What does the roam_create_block tool do? +

Add a new block to an existing Roam page. If no page specified, adds to today's daily note. It is categorised as a Write tool in the Roam Research 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 roam_create_block? +

Register the Roam Research MCP Server MCP server in PolicyLayer and add a rule for roam_create_block: 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 Roam Research MCP Server. Nothing to install.

What risk level is roam_create_block? +

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

Can I rate-limit roam_create_block? +

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

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

roam_create_block is provided by the Roam Research MCP Server MCP server (philosolares/roam-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Roam Research MCP Server tool call.

Start from Roam Research 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 →