Crypto Fear & Greed Index — 0–100 market sentiment (0 = Extreme Fear, 100 = Extreme Greed), updated daily, with classification. Pass limit (1–90) for recent history. Contrarian sentiment signal. Source: alternative.me.
AI agents call crypto.fear-greed to retrieve information from Mcp without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This is a read-only data retrieval tool that queries a public sentiment index. No side effects, no state changes, no code execution, no financial transactions (despite the server's pay-per-call USDC settlement, the tool itself does not move money). The contrarian sentiment signal use case is informational only.
From the tool's definition Tool retrieves market sentiment data (Fear & Greed Index with 0-100 scale) and historical values via optional limit parameter.
Attacks that exploit this kind of access
Crypto Fear & Greed Index — 0–100 market sentiment (0 = Extreme Fear, 100 = Extreme Greed), updated daily, with classification. Pass limit (1–90) for recent history. Contrarian sentiment signal. Source: alternative.me. It is categorised as a Read tool in the Mcp MCP Server, which means it retrieves data without modifying state.
Register the MCP server in PolicyLayer and add a rule for crypto.fear-greed: 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 Mcp. Nothing to install.
crypto.fear-greed 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 crypto.fear-greed 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 crypto.fear-greed. 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.
crypto.fear-greed is provided by the MCP server (@2sio/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
Teams ship this data inside their own products. See what a licence covers →