This record as markdown: /tools/nasbridge/app-stop.md
What app_stop does on Nasbridge
AI agents invoke app_stop to trigger actions in Nasbridge. 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 app_stop is rated High
This tool executes an operation to halt a running application, which qualifies as Execute rather than Write. The blast radius is high because stopping critical apps could cause service outages, data loss in flight, or cascading failures in a TrueNAS infrastructure. The tool accepts an app ID argument, making the effect dependent on what application the AI targets.
From the tool's definition Tool description: 'Stop a running app by its ID.' The action 'stop' on a running application is an external operation that triggers state changes on the TrueNAS system.
Attacks that exploit this kind of access
The rule that runs app_stop safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Nasbridge, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For app_stop, this is the rule to start with:
app_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.
The button opens the PolicyLayer dashboard: create your workspace, connect Nasbridge, apply this rule, and every app_stop call is checked against it from then on.
Questions about app_stop
Stop a running app by its ID. It is categorised as a Execute tool in the Nasbridge MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Nasbridge MCP server in PolicyLayer and add a rule for app_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 Nasbridge. Nothing to install.
app_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 app_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 app_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.
app_stop is provided by the Nasbridge MCP server (maverick0628/nasbridge). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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