ledger_sign_psbt · Bitcoin wallet MCP server MCP

WHAT IT DOES

What ledger_sign_psbt does on Bitcoin wallet MCP server

AI agents use ledger_sign_psbt to commit financial operations through Bitcoin wallet MCP server — usually the final step of a payment, billing, or trading workflow. A call moves real money.

WHY IT NEEDS A POLICY

Why ledger_sign_psbt needs a policy

Signing a PSBT (Partially Signed Bitcoin Transaction) is a direct step in authorizing and committing a Bitcoin financial transaction. Once signed, a PSBT can be broadcast to move funds irreversibly on the Bitcoin network.

From the tool's definition Sign a PSBT using the Ledger Bitcoin app

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

ledger_sign_psbt Approval-gated

Any call to ledger_sign_psbt is blocked until a human approves it. The rest of the server keeps working.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "ledger_sign_psbt": {
      "deny_if": [
        {
          "conditions": [],
          "on_deny": "Requires human approval."
        }
      ]
    }
  }
}

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PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Bitcoin wallet MCP server, so you can run agents against it safely.

FAQ

Questions about ledger_sign_psbt

What does the ledger_sign_psbt tool do? +

Sign a PSBT using the Ledger Bitcoin app. Requires Ledger. It is categorised as a Financial tool in the Bitcoin wallet MCP server MCP Server, which means it involves financial transactions. Block by default and require explicit approval.

How do I enforce a policy on ledger_sign_psbt? +

Register the Bitcoin wallet MCP server MCP server in PolicyLayer and add a rule for ledger_sign_psbt: 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.

What risk level is ledger_sign_psbt? +

ledger_sign_psbt is a Financial tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit ledger_sign_psbt? +

Yes. Add a rate_limit block to the ledger_sign_psbt 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.

How do I block ledger_sign_psbt completely? +

Set action: deny in the PolicyLayer policy for ledger_sign_psbt. 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.

What MCP server provides ledger_sign_psbt? +

ledger_sign_psbt 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.