sparql_query · MCP Wikidata Server MCP: Risk & Policy

WHAT IT DOES

What sparql_query does on MCP Wikidata Server

AI agents invoke sparql_query to trigger actions in MCP Wikidata Server. 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 sparql_query needs a policy

SPARQL queries are executed against Wikidata's endpoint. While Wikidata's public SPARQL endpoint is read-only (SELECT/CONSTRUCT/ASK), the tool name and description say 'execute a query' rather than 'retrieve data', and arbitrary SPARQL could be used for complex or resource-intensive operations.

From the tool's definition 'Execute a SPARQL query against Wikidata' — the tool runs arbitrary SPARQL queries against an external endpoint

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

sparql_query Rate-limited

sparql_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": {
    "sparql_query": {
      "limits": [
        {
          "counter": "sparql_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 MCP Wikidata Server, so you can run agents against it safely.

FAQ

Questions about sparql_query

What does the sparql_query tool do? +

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

How do I enforce a policy on sparql_query? +

Register the MCP Wikidata Server MCP server in PolicyLayer and add a rule for sparql_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 MCP Wikidata Server. Nothing to install.

What risk level is sparql_query? +

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

Can I rate-limit sparql_query? +

Yes. Add a rate_limit block to the sparql_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 sparql_query completely? +

Set action: deny in the PolicyLayer policy for sparql_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 sparql_query? +

sparql_query is provided by the MCP Wikidata Server MCP server (joelgombin/mcp-wikidata). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.