Returns historical CMC Crypto Fear and Greed Index values.
AI agents call fearAndGreedHistorical to retrieve information from CoinMarketCap MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves historical market sentiment data (Fear and Greed Index values) from the CoinMarketCap API. It performs a query operation that returns data without creating, modifying, deleting, or executing any code.
From the tool's definition Tool name 'fearAndGreedHistorical' and description 'Returns historical CMC Crypto Fear and Greed Index values' indicate retrieval of existing data with no side effects or modifications.
Documented attack patterns abuse exactly the kind of access fearAndGreedHistorical gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and CoinMarketCap MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for fearAndGreedHistorical:
{
"version": "1",
"default": "deny",
"tools": {
"fearAndGreedHistorical": {}
}
}fearAndGreedHistorical is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Returns historical CMC Crypto Fear and Greed Index values. It is categorised as a Read tool in the CoinMarketCap MCP MCP Server, which means it retrieves data without modifying state.
Register the CoinMarketCap MCP server in PolicyLayer and add a rule for fearAndGreedHistorical: 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 CoinMarketCap MCP. Nothing to install.
fearAndGreedHistorical 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 fearAndGreedHistorical 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 fearAndGreedHistorical. 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.
fearAndGreedHistorical is provided by the CoinMarketCap MCP server (shinzo-labs/coinmarketcap-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 51 CoinMarketCap MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
51 CoinMarketCap MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.