Stop an active stream (U64 only)
AI agents invoke stream_stop to trigger actions in Commodore 64 Ultimate Computer MCP 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.
This tool executes a command to terminate an active stream on the U64 device. While it does not create, modify, or delete data persistently, it is an active control operation that triggers state changes in an external system (stopping audio/video playback or data streaming). This fits the Execute category as it runs a command whose effects depend on what stream is currently active.
From the tool's definition Tool named 'stream_stop' with description 'Stop an active stream (U64 only)' - the action of stopping a stream is an operation that triggers external control of the Commodore 64 device, similar to a command execution that halts an ongoing process.
Documented attack patterns abuse exactly the kind of access stream_stop 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 stream_stop:
{
"version": "1",
"default": "deny",
"tools": {
"stream_stop": {
"limits": [
{
"counter": "stream_stop_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}stream_stop 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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Stop an active stream (U64 only). It is categorised as a Execute tool in the Commodore 64 Ultimate Computer MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Commodore 64 Ultimate Computer MCP Server MCP server in PolicyLayer and add a rule for stream_stop: 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.
stream_stop 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 stream_stop 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 stream_stop. 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.
stream_stop 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.