This record as markdown: /tools/io-github-kivanccakmak-yaver/preview-stop-all.md
What preview_stop_all does on Yaver
AI agents invoke preview_stop_all to trigger actions in Yaver. 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 preview_stop_all is rated High
This tool executes a command to stop all active preview environments. While not destructive (data and configuration remain), it is Execute because it triggers external operations and has immediate side effects on running services. Severity is high because stopping all previews could disrupt development workflows and impact multiple users or projects simultaneously.
From the tool's definition Tool name 'preview_stop_all' and description 'Stop all preview environments' indicate it halts running processes/services.
Risk signalsBulk/mass operation — affects multiple targets
Attacks that exploit this kind of access
The rule that runs preview_stop_all safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Yaver, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For preview_stop_all, this is the rule to start with:
preview_stop_all 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 Yaver, apply this rule, and every preview_stop_all call is checked against it from then on.
Questions about preview_stop_all
Stop all preview environments. It is categorised as a Execute tool in the Yaver MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Yaver MCP server in PolicyLayer and add a rule for preview_stop_all: 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 Yaver. Nothing to install.
preview_stop_all 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 preview_stop_all 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 preview_stop_all. 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.
preview_stop_all is provided by the Yaver MCP server (yaver-cli). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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