AI agents call readNote to retrieve information from Obsidian MCP REST Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves data from an Obsidian vault without modifying, deleting, or executing anything. It is a straightforward data retrieval operation analogous to a file read or query. No blast radius from misuse—worst case is information disclosure of existing vault contents.
From the tool's definition Tool name 'readNote' and description 'Read the contents of a specific note' explicitly indicate a read-only operation with no side effects.
Documented attack patterns abuse exactly the kind of access readNote gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Obsidian MCP REST Server, and nothing reaches the server without passing your rules. This is the rule we recommend for readNote:
{
"version": "1",
"default": "deny",
"tools": {
"readNote": {}
}
}readNote is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Read the contents of a specific note. It is categorised as a Read tool in the Obsidian MCP REST Server MCP Server, which means it retrieves data without modifying state.
Register the Obsidian MCP REST Server MCP server in PolicyLayer and add a rule for readNote: 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 REST Server. Nothing to install.
readNote is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the readNote 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.
Set action: deny in the PolicyLayer policy for readNote. 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.
readNote is provided by the Obsidian MCP REST Server MCP server (publikprinciple/obsidian-mcp-rest). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 5 Obsidian MCP REST Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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5 Obsidian MCP REST Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.