AI agents call get_fungible_by_id to retrieve information from Zerion without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and queries cryptocurrency asset data by ID. It performs a read-only lookup with no side effects, no code execution, no financial transactions, and no data modification. The operation is limited to fetching publicly available or user-accessible asset information from the Zerion API. Severity is low because misuse would only result in information disclosure, not financial loss or system compromise.
From the tool's definition Tool name 'get_fungible_by_id' and description 'Get detailed info on a specific fungible asset by Zerion ID' indicate a retrieval operation that queries asset information without modifying or executing any transactions.
Attacks that exploit this kind of access
Get detailed info on a specific fungible asset by Zerion ID. It is categorised as a Read tool in the Zerion MCP Server, which means it retrieves data without modifying state.
Register the Zerion MCP server in PolicyLayer and add a rule for get_fungible_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 Zerion. Nothing to install.
get_fungible_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_fungible_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_fungible_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_fungible_by_id is provided by the Zerion MCP server (rockyale/zerion-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.
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