create_file

THE RISK

Medium Risk

Why create_file needs a policy

This tool creates new files in an Obsidian vault, which is a reversible write operation. It modifies the vault's file system by adding new content. While reversible (files can be deleted), the severity is medium because an agent could create large numbers of files, fill storage, or create misleading notes that confuse users.

From the tool's definition Tool name 'create_file' and description 'Creates a new file with the specified content at the given path' directly indicate data creation/modification.

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

POLICY

How to control create_file

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

policy.json

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

create_file 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 Obsidian 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 Obsidian MCP Server tools

Destructive delete_file Deletes a file within your Obsidian Vault. Provide the Destructive delete_folder Deletes a folder within your Obsidian Vault. Provide the Write create_folder Creates a folder within your Obsidian Vault. Provide the Write create_link Creates an Obsidian wikilink from one note to another (e.g., Write edit_file Edits a specific range of lines within a file in your Obsidian Vault. Replaces the content Read count_entries Counts the number of indexed notes and chunks in your Obsidian Vault Read list_files Lists files and sub-folders within a specified directory of your Obsidian Vault. Use Read read_file Reads the full content of a specific note or file within your Obsidian Vault. Provide the

All 10 Obsidian 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 create_file

What does the create_file tool do? +

Creates a new file with the specified content at the given path within your Obsidian Vault. This tool will fail if a file already exists at the specified. It is categorised as a Write tool in the Obsidian 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 create_file? +

Register the Obsidian MCP Server MCP server in PolicyLayer and add a rule for create_file: 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 Obsidian MCP Server. Nothing to install.

What risk level is create_file? +

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

Can I rate-limit create_file? +

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

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

create_file is provided by the Obsidian MCP Server MCP server (minhao-zhang/obsidian-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Obsidian MCP Server tool call.

Start from Obsidian 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 →