AI agents call find_large_notes to retrieve information from Obsidian MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries or filters existing notes based on a size metric and returns results. It has no side effects, does not modify data, execute code, or perform destructive actions. It is purely a read operation for discovery and analysis within the Obsidian vault.
From the tool's definition Tool name 'find_large_notes' and description 'Notes exceeding size threshold' indicate a search/query operation that retrieves information about notes meeting a size criterion. No modification, deletion, or execution capability is implied.
Documented attack patterns abuse exactly the kind of access find_large_notes gives an agent:
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 find_large_notes:
{
"version": "1",
"default": "deny",
"tools": {
"find_large_notes": {}
}
}find_large_notes is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Notes exceeding size threshold. It is categorised as a Read tool in the Obsidian MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Obsidian MCP Server MCP server in PolicyLayer and add a rule for find_large_notes: 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.
find_large_notes 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 find_large_notes 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 find_large_notes. 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.
find_large_notes is provided by the Obsidian MCP Server MCP server (kynlos/obsidian-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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.
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120 Obsidian MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.