Detect and return the currently active C64 screen mode and memory configuration. Reads CIA2 ($DD00) and VIC register ($D018) to properly detect custom screen memory locations (not just standard $0400). Returns mode enum, VIC bank info, screen/char/bitmap addresses, and flags for non-standard conf...
AI agents call get_screen_mode to retrieve information from Commodore 64 Ultimate Computer MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves information about the current screen mode and memory configuration of a Commodore 64 device. It performs only read operations (detecting and returning values from registers) with no side effects, no code execution, no data modification, and no destructive actions. This clearly falls under the Read category.
From the tool's definition Tool description states it 'Detect and return the currently active C64 screen mode' and 'Reads CIA2 and VIC register' — these are read-only operations that query the current state without modifying or executing anything.
Documented attack patterns abuse exactly the kind of access get_screen_mode gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Commodore 64 Ultimate Computer MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for get_screen_mode:
{
"version": "1",
"default": "deny",
"tools": {
"get_screen_mode": {}
}
}get_screen_mode is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Detect and return the currently active C64 screen mode and memory configuration. Reads CIA2 ($DD00) and VIC register ($D018) to properly detect custom screen memory locations (not just standard $0400). Returns mode enum, VIC bank info, screen/char/bitmap addresses, and flags for non-standard configurations used by demos, games, and tools like TASM. It is categorised as a Read tool in the Commodore 64 Ultimate Computer MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Commodore 64 Ultimate Computer MCP Server MCP server in PolicyLayer and add a rule for get_screen_mode: 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 Commodore 64 Ultimate Computer MCP Server. Nothing to install.
get_screen_mode is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the get_screen_mode 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 get_screen_mode. 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.
get_screen_mode is provided by the Commodore 64 Ultimate Computer MCP Server MCP server (xphileby/c64u-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Commodore 64 Ultimate Computer MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
54 Commodore 64 Ultimate Computer MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.