read_file

THE RISK

Low Risk

Why read_file needs a policy

This tool retrieves data from the Obsidian vault without side effects. It performs a read-only operation on existing files, fitting the Read category definition of 'retrieves or queries data; no side effects'. The low severity reflects that unauthorized reads of personal notes, while potentially containing sensitive information, do not result in data loss or system compromise.

From the tool's definition Tool name is 'read_file' and description states it 'Reads the full content of a specific note or file' with no mention of modification, deletion, or execution capabilities.

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

POLICY

How to control read_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 read_file:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "read_file": {}
  }
}

read_file is read-only, so it stays allowed — but 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.

CAP 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_file Creates a new file with the specified content at the given path within your Obsidian Vault 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

All 10 Obsidian MCP Server tools →

Read 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.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about read_file

What does the read_file tool do? +

Reads the full content of a specific note or file within your Obsidian Vault. Provide the. It is categorised as a Read tool in the Obsidian MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on read_file? +

Register the Obsidian MCP Server MCP server in PolicyLayer and add a rule for read_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 read_file? +

read_file is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit read_file? +

Yes. Add a rate_limit block to the read_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 read_file completely? +

Set action: deny in the PolicyLayer policy for read_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 read_file? +

read_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 →