Bitcoin transaction lookup by txid (free/keyless): confirmed status + confirmation count (vs current tip), block height + time, fee (sats + BTC), total output value, size/weight, and input/output counts. Distinct from crypto.tx (EVM) — this is Bitcoin.
AI agents call crypto.btc-tx to retrieve information from Mcp without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves public blockchain data about Bitcoin transactions. It queries immutable historical information and returns read-only results. There is no capability to create, modify, delete, execute code, or move funds. The 'pay-per-call' settlement mechanism of the parent server does not change the tool's own risk category—the transaction lookup itself is a pure read operation.
From the tool's definition Tool performs transaction lookup and retrieval operations: 'lookup by txid', 'confirmed status', 'confirmation count', 'block height + time', 'fee', 'total output value', 'size/weight', 'input/output counts'.
Attacks that exploit this kind of access
Bitcoin transaction lookup by txid (free/keyless): confirmed status + confirmation count (vs current tip), block height + time, fee (sats + BTC), total output value, size/weight, and input/output counts. Distinct from crypto.tx (EVM) — this is Bitcoin. It is categorised as a Read tool in the Mcp MCP Server, which means it retrieves data without modifying state.
Register the MCP server in PolicyLayer and add a rule for crypto.btc-tx: 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 Mcp. Nothing to install.
crypto.btc-tx 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 crypto.btc-tx 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 crypto.btc-tx. 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.
crypto.btc-tx is provided by the MCP server (@2sio/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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