Score any LLM prompt for quality using PQS. Returns a grade (A-F), score out of 40, and percentile. Free — no payment required. Use before sending any prompt to an LLM.
Part of the PQS - Prompt Quality Score server.
Free to start. No card required.
AI agents call score_prompt to retrieve information from PQS - Prompt Quality Score without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though score_prompt only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
{
"version": "1",
"default": "deny",
"tools": {
"score_prompt": {}
}
}See the full PQS - Prompt Quality Score policy for all 3 tools.
These attack patterns abuse exactly the kind of access score_prompt gives an agent. Each links to the full case and the policy that stops it:
Other read tools across the catalogue. The same approach applies to each: allow, with a rate cap to control cost.
Score any LLM prompt for quality using PQS. Returns a grade (A-F), score out of 40, and percentile. Free — no payment required. Use before sending any prompt to an LLM.. It is categorised as a Read tool in the PQS - Prompt Quality Score MCP Server, which means it retrieves data without modifying state.
Register the PQS - Prompt Quality Score MCP server in PolicyLayer and add a rule for score_prompt: 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 PQS - Prompt Quality Score. Nothing to install.
score_prompt 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 score_prompt 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 score_prompt. 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.
score_prompt is provided by the PQS - Prompt Quality Score MCP server (onchaintel/pqs). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 3 PQS - Prompt Quality Score tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
4,600+ MCP servers and 31,000+ tools scanned and risk-classified.