Preview a buy or sell without executing.
AI agents call preview_trade to retrieve information from Basis 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 information about a potential trade (price estimates, slippage calculations, etc.) but performs no actual transaction, fund transfer, or state modification. It is purely informational and matches the Read category definition of 'retrieves or queries data; no side effects.' Misuse by an AI agent would have minimal blast radius since no real assets are at risk.
From the tool's definition Tool description explicitly states 'Preview a buy or sell without executing.' The word 'preview' combined with 'without executing' indicates this is a read-only operation that retrieves simulation or estimation data without side effects.
Attacks that exploit this kind of access
Preview a buy or sell without executing. It is categorised as a Read tool in the Basis MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Basis MCP Server MCP server in PolicyLayer and add a rule for preview_trade: 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 Basis MCP Server. Nothing to install.
preview_trade 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 preview_trade 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 preview_trade. 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.
preview_trade is provided by the Basis MCP Server MCP server (launch-on-basis/mcp-ts). 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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