Run a standard evaluation using a Scorable evaluator by name
AI agents invoke run_evaluation_by_name to trigger actions in Root Signals MCP 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.
This tool triggers external evaluation operations whose effects depend on which evaluator is invoked and what content is evaluated. While not directly destructive or financial, it executes arbitrary evaluator logic that could have side effects on response analysis, data processing, or downstream systems.
From the tool's definition Tool performs 'Run a standard evaluation' which executes an evaluator against responses; evaluators are external operations that process and assess AI-generated content based on specified criteria (clarity, relevance, faithfulness).
Documented attack patterns abuse exactly the kind of access run_evaluation_by_name gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Root Signals MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for run_evaluation_by_name:
{
"version": "1",
"default": "deny",
"tools": {
"run_evaluation_by_name": {
"limits": [
{
"counter": "run_evaluation_by_name_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}run_evaluation_by_name 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.
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Run a standard evaluation using a Scorable evaluator by name. It is categorised as a Execute tool in the Root Signals MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Root Signals MCP Server MCP server in PolicyLayer and add a rule for run_evaluation_by_name: 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 Root Signals MCP Server. Nothing to install.
run_evaluation_by_name is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the run_evaluation_by_name 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 run_evaluation_by_name. 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.
run_evaluation_by_name is provided by the Root Signals MCP Server MCP server (root-signals/scorable-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Root Signals MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
6 Root Signals MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.