Find notes containing a specific tag.
AI agents call search_by_tag to retrieve information from Obsidian Self without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Even though search_by_tag only reads data, uncontrolled read access leaks sensitive information and racks up API costs — an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.
Attacks that exploit this kind of access
Find notes containing a specific tag. It is categorised as a Read tool in the Obsidian Self MCP Server, which means it retrieves data without modifying state.
Register the Obsidian Self MCP server in PolicyLayer and add a rule for search_by_tag: 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 Self. Nothing to install.
search_by_tag 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_tag 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_tag. 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_tag is provided by the Obsidian Self MCP server (suhasvemuri/obsidian-self-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.