finalize_btc_psbt

SERVERVaultPilot MCP SOURCEvaultpilot-mcp

Critical RISK CLASS

Category Financial

Parameters 21 required

Recommended Approval-gatedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/io-github-szhygulin-vaultpilot-mcp/finalize-btc-psbt.md

WHAT IT DOES

What finalize_btc_psbt does on VaultPilot MCP

AI agents use finalize_btc_psbt to commit financial operations through VaultPilot MCP, usually the final step of a payment, billing, or trading workflow. A call moves real money.

Parameter	Type	Required	Description
`broadcast`	boolean	—	When true, broadcasts the finalized tx via the configured indexer and returns `broadcastedTxid` alongside `txid`. When false (default), only returns the tx hex
`psbtBase64`	string	Yes	Base64-encoded PSBT v0 with all required signatures spliced in (typically via `combine_btc_psbts`). Refused with a per-input breakdown when any input is below i

Parameters from the server's own tool schema.

RISK

Why finalize_btc_psbt is rated Critical

Finalizing and broadcasting Bitcoin transactions constitutes direct movement of cryptocurrency funds. Even though it requires pre-signing via multi-sig, the tool itself executes the final step that irreversibly commits the transaction to the blockchain. This is a Financial action with critical severity due to the potential for large-value fund transfers and the blockchain's immutability.

From the tool's definition Tool 'finalize_btc_psbt' finalizes a multi-sig PSBT and extracts broadcast-ready tx hex with optional immediate broadcast ('broadcast: true' to send via configured indexer). This commits cryptocurrency transactions to blockchain.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs finalize_btc_psbt safely

PolicyLayer is an MCP gateway: it sits between your AI agents and VaultPilot MCP, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For finalize_btc_psbt, this is the rule to start with:

finalize_btc_psbt Approval-gated

Any call to finalize_btc_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": {
    "finalize_btc_psbt": {
      "deny_if": [
        {
          "conditions": [],
          "on_deny": "Requires human approval."
        }
      ]
    }
  }
}

GATE THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect VaultPilot MCP, apply this rule, and every finalize_btc_psbt call is checked against it from then on.

FAQ

Questions about finalize_btc_psbt

What does the finalize_btc_psbt tool do? +

Finalize a fully-signed multi-sig PSBT (typically the output of combine_btc_psbts once the threshold is met) and extract the broadcast-ready tx hex. Refuses with a per-input breakdown when any input is below its threshold (e.g. "input 0: 1/2 signatures"). Pass broadcast: true to send via the configured indexer in the same call — returns broadcastedTxid on success. Pass broadcast: false (default) when the caller wants to inspect the hex first or broadcast through a different relay. No device touch. It is categorised as a Financial tool in the VaultPilot MCP MCP Server, which means it involves financial transactions. Block by default and require explicit approval.

What parameters does finalize_btc_psbt accept? +

finalize_btc_psbt accepts 2 parameters: broadcast, psbtBase64. Required: psbtBase64. The full parameter table on this page comes from the server's own tool schema.

How do I enforce a policy on finalize_btc_psbt? +

Register the VaultPilot MCP server in PolicyLayer and add a rule for finalize_btc_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 VaultPilot MCP. Nothing to install.

What risk level is finalize_btc_psbt? +

finalize_btc_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 finalize_btc_psbt? +

Yes. Add a rate_limit block to the finalize_btc_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 finalize_btc_psbt completely? +

Set action: deny in the PolicyLayer policy for finalize_btc_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 finalize_btc_psbt? +

finalize_btc_psbt is provided by the VaultPilot MCP server (vaultpilot-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

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