viewer_clear · PyNet Bridge MCP: Risk & Policy

WHAT IT DOES

What viewer_clear does on PyNet Bridge

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

WHY IT NEEDS A POLICY

Why viewer_clear needs a policy

This tool modifies the state of the viewer UI by removing visual elements (highlights and ghosting). It is reversible since highlights/ghosting can be reapplied. It does not delete data, execute code, or perform financial operations, making Write the most appropriate category. Severity is low as it only affects visual presentation in a viewer.

From the tool's definition Clears highlights and ghosting in the open viewer

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

viewer_clear Rate-limited

viewer_clear 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": {
    "viewer_clear": {
      "limits": [
        {
          "counter": "viewer_clear_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 PyNet Bridge, so you can run agents against it safely.

FAQ

Questions about viewer_clear

What does the viewer_clear tool do? +

Clears highlights and ghosting in the open viewer. It is categorised as a Write tool in the PyNet Bridge MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on viewer_clear? +

Register the PyNet Bridge MCP server in PolicyLayer and add a rule for viewer_clear: 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 PyNet Bridge. Nothing to install.

What risk level is viewer_clear? +

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

Can I rate-limit viewer_clear? +

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

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

viewer_clear is provided by the PyNet Bridge MCP server (rafael-nunezdearenas/pynetbridge). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.