update_viz · HoloViz MCP Server MCP: Risk & Policy

WHAT IT DOES

What update_viz does on HoloViz MCP Server

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

WHY IT NEEDS A POLICY

Why update_viz needs a policy

The tool's name and the pattern of sibling tools (create_viz, annotate_viz, handle_interaction) suggest this modifies an existing visualization object rather than executing arbitrary code or creating destructive effects. Updating a visualization is a reversible write operation with limited blast radius—at worst it corrupts the current visualization state, which can be recovered by recreating it.

From the tool's definition Tool name 'update_viz' indicates modification of visualization state or properties. The server context describes creating and rendering interactive visualizations.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_viz Rate-limited

update_viz 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": {
    "update_viz": {
      "limits": [
        {
          "counter": "update_viz_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 HoloViz MCP Server, so you can run agents against it safely.

FAQ

Questions about update_viz

What does the update_viz tool do? +

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

How do I enforce a policy on update_viz? +

Register the HoloViz MCP Server MCP server in PolicyLayer and add a rule for update_viz: 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 HoloViz MCP Server. Nothing to install.

What risk level is update_viz? +

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

Can I rate-limit update_viz? +

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

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

update_viz is provided by the HoloViz MCP Server MCP server (sumayabee/holoviz-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.