AI agents invoke android_show_toast to trigger actions in MCP Prompts 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 an action on an Android device (displaying a toast notification), which constitutes triggering an external operation. While relatively benign, it interacts with a real device and could be used to display misleading messages to users. It falls under Execute as it performs a device-level action with side effects.
From the tool's definition 'Show a toast message on Android device' — triggers an external operation on a physical/virtual Android device
Documented attack patterns abuse exactly the kind of access android_show_toast gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP Prompts Server, and nothing reaches the server without passing your rules. This is the rule we recommend for android_show_toast:
{
"version": "1",
"default": "deny",
"tools": {
"android_show_toast": {
"limits": [
{
"counter": "android_show_toast_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}android_show_toast 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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Show a toast message on Android device. It is categorised as a Execute tool in the MCP Prompts Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the MCP Prompts Server MCP server in PolicyLayer and add a rule for android_show_toast: 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 MCP Prompts Server. Nothing to install.
android_show_toast 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 android_show_toast 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 android_show_toast. 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.
android_show_toast is provided by the MCP Prompts Server MCP server (sparesparrow/mcp-prompts). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 51 MCP Prompts Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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51 MCP Prompts Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.