browser_evaluate_game_state · DevLab MCP Suite MCP

WHAT IT DOES

What browser_evaluate_game_state does on DevLab MCP Suite

AI agents invoke browser_evaluate_game_state to trigger actions in DevLab MCP Suite. 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 browser_evaluate_game_state needs a policy

This tool executes arbitrary JavaScript in a browser page context. Despite the stated purpose of inspecting game state, it can run any JS code, making it an Execute-category tool. The blast radius is high because arbitrary JS execution in a page context can access cookies, localStorage, make network requests, modify DOM, and exfiltrate data.

From the tool's definition 'Evaluate a JavaScript expression' and 'Expression runs in page context'

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

browser_evaluate_game_state Rate-limited

browser_evaluate_game_state 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": {
    "browser_evaluate_game_state": {
      "limits": [
        {
          "counter": "browser_evaluate_game_state_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 DevLab MCP Suite, so you can run agents against it safely.

FAQ

Questions about browser_evaluate_game_state

What does the browser_evaluate_game_state tool do? +

Evaluate a JavaScript expression to inspect game state (score, level, lives, etc.). Expression runs in page context. It is categorised as a Execute tool in the DevLab MCP Suite MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on browser_evaluate_game_state? +

Register the DevLab MCP Suite MCP server in PolicyLayer and add a rule for browser_evaluate_game_state: 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 DevLab MCP Suite. Nothing to install.

What risk level is browser_evaluate_game_state? +

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

Can I rate-limit browser_evaluate_game_state? +

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

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

browser_evaluate_game_state is provided by the DevLab MCP Suite MCP server (tanguito86/devlab-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.