Search for notes by tags (supports both frontmatter and inline tags)
AI agents call search-by-tags 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.
Search-by-tags retrieves or queries vault data (notes matching specified tags) with no side effects. It falls squarely into the Read category—analogous to list or filter operations. No data is created, modified, deleted, or executed. Severity is low because misuse by an AI agent would at worst over-retrieve information about the vault's structure and content, with no destructive or operational impact.
From the tool's definition Tool name is 'search-by-tags' and description states it 'Search for notes by tags' — a query operation that retrieves matching notes without modifying data.
Documented attack patterns abuse exactly the kind of access search-by-tags 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-by-tags:
{
"version": "1",
"default": "deny",
"tools": {
"search-by-tags": {}
}
}search-by-tags 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 by tags (supports both frontmatter and inline 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-by-tags: 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-by-tags 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-by-tags 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-by-tags. 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-by-tags is provided by the Obsidian MCP Server MCP server (piotr1215/mcp-obsidian). 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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9 Obsidian MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.