pinchtab_eval · Pinchtab MCP: Risk & Policy

WHAT IT DOES

What pinchtab_eval does on Pinchtab

AI agents invoke pinchtab_eval to trigger actions in Pinchtab. 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.

WHY IT NEEDS A POLICY

Why pinchtab_eval needs a policy

This tool allows arbitrary JavaScript execution within a browser page context, which can perform any action the JavaScript environment permits: read sensitive data, modify DOM, trigger network requests, interact with page APIs, steal credentials, or exfiltrate information.

From the tool's definition Execute JavaScript code in the page context. Returns the result of the expression.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

pinchtab_eval Rate-limited

pinchtab_eval 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "pinchtab_eval": {
      "limits": [
        {
          "counter": "pinchtab_eval_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about pinchtab_eval

What does the pinchtab_eval tool do? +

Execute JavaScript code in the page context. Returns the result of the expression. It is categorised as a Execute tool in the Pinchtab MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on pinchtab_eval? +

Register the Pinchtab MCP server in PolicyLayer and add a rule for pinchtab_eval: 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 Pinchtab. Nothing to install.

What risk level is pinchtab_eval? +

pinchtab_eval is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit pinchtab_eval? +

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

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

pinchtab_eval is provided by the Pinchtab MCP server (maderwin/pinchtab-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

// THE FULL RECORD

pinchtab_eval is one line of Pinchtab's registry record.

The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.

Teams ship this data inside their own products. See what a licence covers →