AI agents call get_historical_price to retrieve information from Cn Financial without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves historical price data without side effects. It queries financial information but does not create, modify, delete, execute code, or involve financial transactions. The absence of a description is partially mitigated by the clear naming convention and the read-only nature of sibling tools on the same server, which strongly suggests this follows the same pattern of passive data access.
From the tool's definition Tool name 'get_historical_price' indicates data retrieval. The server description confirms it 'Provides access to Chinese mainland financial data including A-stock quotes' with no mention of modification, deletion, or execution capabilities.
Documented attack patterns abuse exactly the kind of access get_historical_price gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Cn Financial, and nothing reaches the server without passing your rules. This is the rule we recommend for get_historical_price:
{
"version": "1",
"default": "deny",
"tools": {
"get_historical_price": {}
}
}get_historical_price is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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get_historical_price. It is categorised as a Read tool in the Cn Financial MCP Server, which means it retrieves data without modifying state.
Register the Cn Financial MCP server in PolicyLayer and add a rule for get_historical_price: 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 Cn Financial. Nothing to install.
get_historical_price is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the get_historical_price 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 get_historical_price. 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.
get_historical_price is provided by the Cn Financial MCP server (ccq1/cn-financial-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Cn Financial, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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42 Cn Financial tools catalogued and risk-classified — across an index of 43,000+ MCP servers.