read_query · Helm Chart CLI MCP: Risk & Policy

WHAT IT DOES

What read_query does on Helm Chart CLI

AI agents invoke read_query to trigger actions in Helm Chart CLI. 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 read_query needs a policy

Although limited to SELECT queries (read-only intent), the tool actively executes SQL against a database engine. Arbitrary SELECT queries can be misused for data exfiltration, timing attacks, or resource exhaustion (e.g., expensive joins). It falls under Execute rather than Read because it runs code/queries on an external system.

From the tool's definition 'Execute a SELECT query on the SQLite database' — the tool runs SQL queries against a database

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

read_query Rate-limited

read_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": {
    "read_query": {
      "limits": [
        {
          "counter": "read_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 Helm Chart CLI, so you can run agents against it safely.

FAQ

Questions about read_query

What does the read_query tool do? +

Execute a SELECT query on the SQLite database. It is categorised as a Execute tool in the Helm Chart CLI MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on read_query? +

Register the Helm Chart CLI MCP server in PolicyLayer and add a rule for read_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 Helm Chart CLI. Nothing to install.

What risk level is read_query? +

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

Can I rate-limit read_query? +

Yes. Add a rate_limit block to the read_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 read_query completely? +

Set action: deny in the PolicyLayer policy for read_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 read_query? +

read_query is provided by the Helm Chart CLI MCP server (jeff-nasseri/servers). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.