Stop a running sandbox. Use force to kill with SIGKILL instead of graceful SIGTERM.
AI agents invoke sandbox_stop to trigger actions in Microsandbox. 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.
Stopping a sandbox is an Execute action because it runs an external operation (process termination signal) that affects running system state. While not strictly destructive to persistent data, it forcibly terminates computational processes and can interrupt ongoing work. The force parameter that allows SIGKILL escalates the impact.
From the tool's definition Tool description states 'Stop a running sandbox. Use force to kill with SIGKILL' — this triggers external process termination operations (SIGTERM/SIGKILL) whose effects depend on which sandbox instance is targeted.
Documented attack patterns abuse exactly the kind of access sandbox_stop gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Microsandbox, and nothing reaches the server without passing your rules. This is the rule we recommend for sandbox_stop:
{
"version": "1",
"default": "deny",
"tools": {
"sandbox_stop": {
"limits": [
{
"counter": "sandbox_stop_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
} sandbox_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.
Free to start. No card required.
Stop a running sandbox. Use force to kill with SIGKILL instead of graceful SIGTERM. It is categorised as a Execute tool in the Microsandbox MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Microsandbox MCP server in PolicyLayer and add a rule for sandbox_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 Microsandbox. Nothing to install.
sandbox_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 sandbox_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 sandbox_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.
sandbox_stop is provided by the Microsandbox MCP server (superradcompany/microsandbox-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Microsandbox, 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.
19 Microsandbox tools catalogued and risk-classified — across an index of 43,000+ MCP servers.