Extract and parse YAML frontmatter from a single note.
AI agents call get_frontmatter to retrieve information from Obsidian Knowledge Management 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 structured metadata (YAML frontmatter) from a note without side effects. It performs data extraction only, matching the Read category definition of querying data with no side effects. The low severity reflects minimal risk if misused by an AI agent—exposure of note metadata is less critical than write, execute, or destructive actions.
From the tool's definition Tool name 'get_frontmatter' and description 'Extract and parse YAML frontmatter from a single note' indicate retrieval of metadata without modification or deletion.
Attacks that exploit this kind of access
Extract and parse YAML frontmatter from a single note. It is categorised as a Read tool in the Obsidian Knowledge Management MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Obsidian Knowledge Management MCP Server MCP server in PolicyLayer and add a rule for get_frontmatter: 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 Knowledge Management MCP Server. Nothing to install.
get_frontmatter 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 get_frontmatter 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 get_frontmatter. 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.
get_frontmatter is provided by the Obsidian Knowledge Management MCP Server MCP server (theoutcastvirus/obsidian-knowledge-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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