AI agents call get_wallet_balance_chart 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 historical balance data for charting purposes. It does not create, modify, delete, or execute any operations—it only fetches existing data. While it provides financial information (crypto portfolio data), it does not move money, commit financial obligations, or trigger any irreversible actions.
From the tool's definition Tool is named 'get_wallet_balance_chart' and described as 'Get historical balance chart data for a wallet.' The verb 'Get' and the passive nature of retrieving chart data indicate a read-only operation with no side effects.
Attacks that exploit this kind of access
Get historical balance chart data for a wallet. 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_wallet_balance_chart: 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_wallet_balance_chart 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_wallet_balance_chart 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_wallet_balance_chart. 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_wallet_balance_chart 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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