query · Frontmatter MCP: Risk & Policy

WHAT IT DOES

What query does on Frontmatter MCP

AI agents invoke query to trigger actions in Frontmatter MCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why query needs a policy

The tool name 'query' combined with the server's use of DuckDB SQL suggests it can execute arbitrary SQL statements. Since the server supports both querying and updating operations, and DuckDB SQL can include destructive statements (DROP, DELETE), this is classified as Execute at minimum. The description is empty, which lowers confidence, but the server context implies SQL execution capabilities.

From the tool's definition Tool name is 'query' on a server that uses DuckDB SQL for querying and updating Markdown frontmatter metadata. The server description mentions 'querying and updating' via DuckDB SQL.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

query Rate-limited

query stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "query": {
      "limits": [
        {
          "counter": "query_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Frontmatter MCP, so you can run agents against it safely.

FAQ

Questions about query

What does the query tool do? +

query. It is categorised as a Execute tool in the Frontmatter MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on query? +

Register the Frontmatter MCP server in PolicyLayer and add a rule for query: 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 Frontmatter MCP. Nothing to install.

What risk level is query? +

query is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit query? +

Yes. Add a rate_limit block to the query 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.

How do I block query completely? +

Set action: deny in the PolicyLayer policy for query. 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.

What MCP server provides query? +

query is provided by the Frontmatter MCP server (kzmshx/frontmatter-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.