Get historical Fear & Greed Index for specified number of days as a tool.
AI agents call get_historical_fng_tool to retrieve information from Crypto Feargreed without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves historical cryptocurrency Fear & Greed Index data. It performs a query operation to fetch existing data without creating, modifying, deleting, or executing any operations. The data returned is informational only and cannot be used to alter state or trigger external actions. Classification as Read is appropriate with low severity since misuse would only expose historical market sentiment data.
From the tool's definition Tool name 'get_historical_fng_tool' and description 'Get historical Fear & Greed Index for specified number of days' indicate data retrieval with no modification or side effects.
Documented attack patterns abuse exactly the kind of access get_historical_fng_tool gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Crypto Feargreed, and nothing reaches the server without passing your rules. This is the rule we recommend for get_historical_fng_tool:
{
"version": "1",
"default": "deny",
"tools": {
"get_historical_fng_tool": {}
}
}get_historical_fng_tool 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 Fear & Greed Index for specified number of days as a tool. It is categorised as a Read tool in the Crypto Feargreed MCP Server, which means it retrieves data without modifying state.
Register the Crypto Feargreed MCP server in PolicyLayer and add a rule for get_historical_fng_tool: 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 Feargreed. Nothing to install.
get_historical_fng_tool 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_fng_tool 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_fng_tool. 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_fng_tool is provided by the Crypto Feargreed MCP server (kukapay/crypto-feargreed-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Crypto Feargreed, 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.
3 Crypto Feargreed tools catalogued and risk-classified — across an index of 43,000+ MCP servers.