AI agents invoke icost_open_app to trigger actions in Icost App. 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 triggers an external operation — navigating/opening specific pages within the iCost iOS app. It executes a UI action rather than reading, writing, or destroying data. Misuse has low blast radius as it only affects app navigation.
From the tool's definition 打开iCost应用的不同页面 (Opens different pages of the iCost application)
Documented attack patterns abuse exactly the kind of access icost_open_app gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Icost App, and nothing reaches the server without passing your rules. This is the rule we recommend for icost_open_app:
{
"version": "1",
"default": "deny",
"tools": {
"icost_open_app": {
"limits": [
{
"counter": "icost_open_app_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}icost_open_app 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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打开iCost应用的不同页面. It is categorised as a Execute tool in the Icost App MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Icost App MCP server in PolicyLayer and add a rule for icost_open_app: 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 Icost App. Nothing to install.
icost_open_app 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 icost_open_app 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 icost_open_app. 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.
icost_open_app is provided by the Icost App MCP server (toolife/icost-app-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Icost App, 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.
4 Icost App tools catalogued and risk-classified — across an index of 43,000+ MCP servers.