AI agents call list_vaults 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 retrieves information about available Obsidian vaults without any side effects. It is a simple query/list operation that does not create, modify, delete, or execute anything. While exposing vault names could reveal organizational structure in a multi-vault setup, the risk is limited to information disclosure without destructive or operational impact.
From the tool's definition Tool name is 'list_vaults' and description states 'List all available vaults' — a pure enumeration operation with no modification, deletion, or execution of arbitrary code.
Documented attack patterns abuse exactly the kind of access list_vaults 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 list_vaults:
{
"version": "1",
"default": "deny",
"tools": {
"list_vaults": {}
}
}list_vaults is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List all available vaults. 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 list_vaults: 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.
list_vaults 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 list_vaults 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 list_vaults. 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.
list_vaults 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.