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.
This tool performs a read-only search operation to retrieve or query notes from an Obsidian vault. It has no side effects, does not create, modify, delete, or execute any code. The blast radius of misuse is minimal—an AI agent could at worst retrieve sensitive note contents, but this is a data access issue rather than a destructive or systemic threat. It clearly falls under the Read category.
From the tool's definition Tool name 'search_notes' and description 'Search for notes in a vault' indicate a query operation with no data modification or execution capability.
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 for notes in a vault. 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 (bazylhorsey/obsidian-mcp-server). 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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29 Obsidian MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.