# register_btc_multisig_wallet

One-time registration of a multi-sig Bitcoin wallet policy with the Ledger BTC app (BIP-388 wallet policies). REQUIREMENTS: Ledger plugged in over USB, device unlocked, the 'Bitcoin' app open on-screen. Constructs a wsh(sortedmulti(M,@0/,@1/,...)) descriptor from the supplied cosigners, verifies the connected Ledger's master fingerprint matches exactly one cosigner slot, calls Ledger's registerWallet (the device walks every cosigner xpub fingerprint on-screen for verification — the user MUST confirm each fingerprint matches what they expect, since this is the moment that anchors the policy), and persists the descriptor + 32-byte HMAC. The HMAC is reused on every subsequent sign_btc_multisig_psbt call so the user only walks the descriptor approval flow once per setup. Phase 2 scope: P2WSH (wsh) only. Hard-validates every cosigner xpub via @scure/bip32 round-trip — typos that would silently register a wallet we can never sign with are refused up-front.

Agent View of the PolicyLayer registry record for `register_btc_multisig_wallet`. HTML page: https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/register-btc-multisig-wallet

## Facts

- Tool: `register_btc_multisig_wallet`
- Server: VaultPilot MCP (`vaultpilot-mcp`) — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp.md
- Install: `npx -y vaultpilot-mcp`
- Homepage: https://github.com/szhygulin/vaultpilot-mcp
- Risk category: Write (Medium risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 4 (4 required)
- Recommended policy verdict: Rate-limited

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `name` | string | yes | User-chosen label for the multi-sig setup, e.g. "Family vault". Must be printable ASCII, ≤ 16 bytes (Ledger BTC app caps wallet-policy names at 16 bytes). Surfa |
| `cosigners` | array | yes | Cosigner slots in the order they should appear in the descriptor's `@N` slots. Slot order is part of the descriptor identity — every cosigner must agree on the |
| `threshold` | integer | yes | M in M-of-N. Must be ≥ 1 and ≤ cosigner count. Phase 2 hard-caps at 15 (the Ledger BTC app's wallet-policy limit). |
| `scriptType` | string | yes | Script type for the multi-sig wrapper. Phase 2 supports "wsh" only (P2WSH native segwit, `bc1q...`-style addresses). Taproot multi-sig and P2SH-wrapped multi-si |

Parameters from the server's own tool schema.

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "register_btc_multisig_wallet",
    "arguments": {
      "name": "<name>",
      "cosigners": [],
      "threshold": 0,
      "scriptType": "<scriptType>"
    }
  }
}
```

## Why register_btc_multisig_wallet is rated Medium

This tool registers a new multisig wallet policy on a Ledger hardware device — a write/configuration operation that anchors the wallet policy on the device. It is not directly moving funds (Financial) nor deleting data (Destructive), but it does establish a persistent cryptographic policy that governs future Bitcoin transactions. Misuse could anchor a malicious multisig policy, making severity high.

From the tool's own definition: "One-time registration of a multi-sig Bitcoin wallet policy with the Ledger BTC app (BIP-388 wallet policies)... Constructs a `wsh(sortedmulti(M,@0/**,@1/**,...))` descriptor from the supplied cosigners... calls Ledger's `registerWallet`"

Risk signals: Bulk/mass operation — affects multiple targets

## Use case

AI agents use register_btc_multisig_wallet to create or update resources in VaultPilot MCP, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your VaultPilot MCP environment.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches VaultPilot MCP:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "register_btc_multisig_wallet": {
      "limits": [
        {
          "counter": "register_btc_multisig_wallet_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on VaultPilot MCP (188)

- `prepare_btc_lifi_swap` — Destructive — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-btc-lifi-swap.md
- `prepare_btc_rbf_bump` — Destructive — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-btc-rbf-bump.md
- `prepare_jito_stake` — Destructive — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-jito-stake.md
- `prepare_marginfi_init` — Destructive — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-marginfi-init.md
- `prepare_solana_nonce_close` — Destructive — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-solana-nonce-close.md
- `prepare_sunswap_swap` — Destructive — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-sunswap-swap.md
- `prepare_uniswap_v3_burn` — Destructive — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-uniswap-v3-burn.md
- `prepare_uniswap_v3_mint` — Destructive — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-uniswap-v3-mint.md
- `remove_contact` — Destructive — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/remove-contact.md
- `unregister_btc_multisig_wallet` — Destructive — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/unregister-btc-multisig-wallet.md
- `combine_btc_psbts` — Execute — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/combine-btc-psbts.md
- `pair_ledger_btc` — Execute — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/pair-ledger-btc.md
- `prepare_aave_repay` — Execute — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-aave-repay.md
- `prepare_btc_multisig_send` — Execute — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-btc-multisig-send.md
- `prepare_compound_repay` — Execute — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-compound-repay.md
- `prepare_compound_supply` — Execute — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-compound-supply.md
- `prepare_curve_swap` — Execute — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-curve-swap.md
- `prepare_custom_call` — Execute — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-custom-call.md
- `prepare_kamino_init_user` — Execute — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-kamino-init-user.md
- `prepare_kamino_supply` — Execute — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-kamino-supply.md
- `prepare_lido_unstake` — Execute — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-lido-unstake.md
- `prepare_lido_unwrap` — Execute — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-lido-unwrap.md
- `prepare_lido_wrap` — Execute — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-lido-wrap.md
- `prepare_native_stake_deactivate` — Execute — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-native-stake-deactivate.md
- `prepare_native_stake_delegate` — Execute — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-native-stake-delegate.md
- `prepare_rocketpool_unstake` — Execute — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-rocketpool-unstake.md
- `prepare_safe_tx_execute` — Execute — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-safe-tx-execute.md
- `prepare_solana_lifi_swap` — Execute — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-solana-lifi-swap.md
- `prepare_solana_nonce_init` — Execute — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-solana-nonce-init.md
- `prepare_solana_swap` — Execute — https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp/prepare-solana-swap.md
- …and 158 more: https://policylayer.com/tools/io-github-szhygulin-vaultpilot-mcp.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=io-github-szhygulin-vaultpilot-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/io-github-szhygulin-vaultpilot-mcp