roam_update_block

THE RISK

Medium Risk

Why roam_update_block needs a policy

This tool creates or modifies data reversibly within the Roam Research graph. Updates to blocks can be undone by users (typical for note-taking applications), making it Write rather than Destructive. The scope is limited to a single block, reducing blast radius compared to batch operations.

From the tool's definition Tool name 'roam_update_block' and description 'Update a single block identified by its UID' explicitly perform modification of existing data in Roam Research graphs.

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

POLICY

How to control roam_update_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_update_block:

policy.json

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

roam_update_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 →

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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_block Add a new block to an existing Roam page. If no page specified, adds to today's daily note Write roam_create_outline roam_create_outline Write roam_create_page roam_create_page Write roam_import_markdown roam_import_markdown

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_update_block

What does the roam_update_block tool do? +

Update a single block identified by its UID. 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_update_block? +

Register the Roam Research MCP Server MCP server in PolicyLayer and add a rule for roam_update_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_update_block? +

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

Can I rate-limit roam_update_block? +

Yes. Add a rate_limit block to the roam_update_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_update_block completely? +

Set action: deny in the PolicyLayer policy for roam_update_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_update_block? +

roam_update_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 →