Preview an STX transfer with fee estimation and balance check.
AI agents call stx_preview_transfer to retrieve information from Bitcoin wallet MCP server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool only previews a transfer — it performs fee estimation and balance checking without actually executing or committing any transaction. No funds are moved, and there are no side effects. This is a read/query operation that simulates what a transfer would look like.
From the tool's definition Preview an STX transfer with fee estimation and balance check
Attacks that exploit this kind of access
Preview an STX transfer with fee estimation and balance check. It is categorised as a Read tool in the Bitcoin wallet MCP server MCP Server, which means it retrieves data without modifying state.
Register the Bitcoin wallet MCP server MCP server in PolicyLayer and add a rule for stx_preview_transfer: 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 Bitcoin wallet MCP server. Nothing to install.
stx_preview_transfer 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 stx_preview_transfer 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 stx_preview_transfer. 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.
stx_preview_transfer is provided by the Bitcoin wallet MCP server MCP server (markmhendrickson/mcp-server-bitcoin). 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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