Return the YAML frontmatter as a formatted YAML string.
AI agents call get_frontmatter to retrieve information from Ast Editor without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and returns frontmatter metadata without creating, modifying, deleting, or executing any operations. It is a pure read operation with minimal blast radius if misused—it can only expose metadata already present in the file.
From the tool's definition Tool name 'get_frontmatter' and description 'Return the YAML frontmatter as a formatted YAML string' indicate retrieval of existing data with no modification.
Documented attack patterns abuse exactly the kind of access get_frontmatter gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Ast Editor, and nothing reaches the server without passing your rules. This is the rule we recommend for get_frontmatter:
{
"version": "1",
"default": "deny",
"tools": {
"get_frontmatter": {}
}
}get_frontmatter is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Return the YAML frontmatter as a formatted YAML string. It is categorised as a Read tool in the Ast Editor MCP Server, which means it retrieves data without modifying state.
Register the Ast Editor 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 Ast Editor. 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 Ast Editor MCP server (kambleakash0/agent-skills). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Ast Editor, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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59 Ast Editor tools catalogued and risk-classified — across an index of 43,000+ MCP servers.