plot_bar · ML Research MCP: Risk & Policy

WHAT IT DOES

What plot_bar does on ML Research MCP

AI agents use plot_bar to create or update resources in ML Research MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your ML Research MCP environment.

WHY IT NEEDS A POLICY

Why plot_bar needs a policy

The description is empty, so classification relies on the tool name and server context. 'plot_bar' is consistent with the sibling tools (plot_box, plot_histogram, plot_scatter, etc.), all of which generate visualization files/outputs. This constitutes a Write action — creating a new artifact (a bar chart file or rendered figure) — with no indication of destructive, financial, or execution behavior.

From the tool's definition Tool name 'plot_bar' on a server described as providing tools for 'creating publication-quality scientific visualizations, statistical plots, and 2D data representations'

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

plot_bar Rate-limited

plot_bar stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "plot_bar": {
      "limits": [
        {
          "counter": "plot_bar_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about plot_bar

What does the plot_bar tool do? +

plot_bar. It is categorised as a Write tool in the ML Research MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on plot_bar? +

Register the ML Research MCP server in PolicyLayer and add a rule for plot_bar: 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 ML Research MCP. Nothing to install.

What risk level is plot_bar? +

plot_bar is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit plot_bar? +

Yes. Add a rate_limit block to the plot_bar 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 plot_bar completely? +

Set action: deny in the PolicyLayer policy for plot_bar. 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 plot_bar? +

plot_bar is provided by the ML Research MCP server (nishide-dev/ml-research-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.