# Step 4 — Derivation / Signer

- **types-signer.ts** — Signer interface (Ethereum-style: getAddress, signTransaction, signPersonalMessage). Use as-is for EVM/Chain 138.
- **getAddress.ts** — getAddress resolver using `@ledgerhq/coin-framework` (GetAddressFn, SignerContext, GetAddressOptions). Register in live-common family setup.

**CLI check (after currency is added):**
```bash
ledger-live getAddress --currency defi_oracle_meta_mainnet --path "44'/60'/0'/0/0" --derivationMode ""
```
Or with ethereum currency and chainId in config:
```bash
ledger-live getAddress --currency ethereum --path "44'/60'/0'/0/0" --derivationMode ""
```

Derivation for Chain 138: **44'/60'/0'/0/0** (standard EVM BIP44).