Get exchange rate for a specific currency by its ID (e.g.,
AI agents call get_rate_by_id to retrieve information from CoinCap MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves static market data (exchange rates) from the CoinCap API. It performs a read-only query with no capacity to modify, execute code, delete data, or transfer funds. The blast radius of misuse is minimal—an agent could only retrieve publicly available cryptocurrency rate information. This is a straightforward data retrieval operation classified as Read with low severity.
From the tool's definition Tool name 'get_rate_by_id' and description 'Get exchange rate for a specific currency by its ID' indicate a retrieval operation with no side effects.
Attacks that exploit this kind of access
Get exchange rate for a specific currency by its ID (e.g.,. It is categorised as a Read tool in the CoinCap MCP Server MCP Server, which means it retrieves data without modifying state.
Register the CoinCap MCP Server MCP server in PolicyLayer and add a rule for get_rate_by_id: 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 CoinCap MCP Server. Nothing to install.
get_rate_by_id 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_rate_by_id 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_rate_by_id. 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_rate_by_id is provided by the CoinCap MCP Server MCP server (sanchello69/mcpserver). 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.
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