AI agents invoke wait_frames to trigger actions in MCP GameBoy Server. 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.
The tool executes an operation (frame advancement) in the GameBoy emulator based on a numerical argument. While the effects are deterministic and limited to timing within the emulator context (no external side effects, no data modification, no deletion), it still represents code/operation execution.
From the tool's definition Tool description states 'Wait for a specified number of frames', which triggers a time-based operation in the GameBoy emulator. This is an execution action that controls the emulator's state progression.
Documented attack patterns abuse exactly the kind of access wait_frames gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP GameBoy Server, and nothing reaches the server without passing your rules. This is the rule we recommend for wait_frames:
{
"version": "1",
"default": "deny",
"tools": {
"wait_frames": {
"limits": [
{
"counter": "wait_frames_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}wait_frames 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.
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Wait for a specified number of frames. It is categorised as a Execute tool in the MCP GameBoy Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the MCP GameBoy Server MCP server in PolicyLayer and add a rule for wait_frames: 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 MCP GameBoy Server. Nothing to install.
wait_frames is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the wait_frames 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.
Set action: deny in the PolicyLayer policy for wait_frames. 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.
wait_frames is provided by the MCP GameBoy Server MCP server (mario-andreschak/mcp-gameboy). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MCP GameBoy Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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5 MCP GameBoy Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.