AI agents call portfolio_value_history to retrieve information from Crypto Portfolio without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool appears to fetch or retrieve historical portfolio value data without modifying state. The naming convention, server context (tracking and querying), and analogy to sibling read-only tools ('get_*') all indicate a retrieval operation with no side effects. The lack of a description introduces minor uncertainty, but the pattern is consistent with Read operations.
From the tool's definition Tool name 'portfolio_value_history' suggests retrieving historical data about portfolio values. The server's stated purpose includes 'query and optimize portfolio strategies in real time', and sibling tools like 'get_portfolio_summary' and 'get_price' are…
Documented attack patterns abuse exactly the kind of access portfolio_value_history gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Crypto Portfolio, and nothing reaches the server without passing your rules. This is the rule we recommend for portfolio_value_history:
{
"version": "1",
"default": "deny",
"tools": {
"portfolio_value_history": {}
}
}portfolio_value_history is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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portfolio_value_history. It is categorised as a Read tool in the Crypto Portfolio MCP Server, which means it retrieves data without modifying state.
Register the Crypto Portfolio MCP server in PolicyLayer and add a rule for portfolio_value_history: 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 Crypto Portfolio. Nothing to install.
portfolio_value_history 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 portfolio_value_history 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 portfolio_value_history. 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.
portfolio_value_history is provided by the Crypto Portfolio MCP server (kukapay/crypto-portfolio-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Crypto Portfolio, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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4 Crypto Portfolio tools catalogued and risk-classified — across an index of 43,000+ MCP servers.