AI agents call search_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.
The search_notes tool retrieves or filters existing notes based on content or tag criteria. It performs a read-only operation typical of search functionality—no data is created, modified, deleted, or executed. This is a standard Read category tool with minimal security risk, as it only exposes information already stored in the user's Obsidian vault.
From the tool's definition Tool name 'search_notes' and description 'Search notes by content or tags' indicate a query/retrieval operation with no modification or side effects.
Documented attack patterns abuse exactly the kind of access search_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 search_notes:
{
"version": "1",
"default": "deny",
"tools": {
"search_notes": {}
}
}search_notes is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Search notes by content or tags. 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 search_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.
search_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 search_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 search_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.
search_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.